1999 MLSSA Journal
THE MARINE
LIFE SOCIETY OF SOUTH AUSTRALIA Inc.ABOUT OUR
SOCIETYAre you interested in any aspect of marine life? Do you want to learn or understand more about the underwater world? Do you want to campaign against the pollution of our oceans and the destruction of reefs and seagrass beds? If so, our Society (MLSSA) caters for people just like you.
Our motto is "--- understanding, enjoying and caring for our oceans ---". These few words summarise our member's motives. Members seek to understand our ocean, derive enjoyment from observations of marine life and are committed to its protection.
Become a Society member and enjoy contact with others with similar interests. Our members include divers, marine aquarists and naturalists. Our aim is to promote a better understanding of our marine environment.
Our activities include:-
-Studying our local marine environment
-Education
-Scuba diving
-Underwater photography
-Temperate marine aquaria
Established in 1976, MLSSA holds monthly meetings and field trips. We produce various informative and educational publications including a monthly Newsletter and an annual Journal. Our library is a source of information for marine enthusiasts.
Through our affiliation with other organisations (Conservation Council of SA and the Scuba Divers Federation of SA) we are kept up to date with relevant local issues. MLSSA also has close ties with appropriate Government organisations, e.g. various museums, universities and libraries.
You can also join our Society. We have subscription levels for students, individuals, families and organisations. We invite you to fill in, or a photocopy of, the membership subscription form in this webpage.
The postal address of the Society is :-
MLSSA Inc.
120 WAKEFIELD STREET,
ADELAIDE 5000.
South Australia
General Meetings
Everyone is welcome to attend our General Meetings on the third Wednesday of every month, except December (when there is no meeting) beginning at 8 pm.
Meetings are usually held at:-
The Conservation Centre,
120 Wakefield Street,
ADELAIDE
Please contact the Society prior to a meeting in case there is a change of venue or read the information in the relevant Newsletter published on this webpage.
Parking is available down the lane on the Eastern side of the building. Please enter via the front door.
OUR LOGO
The MLSSA logo features a Leafy Seadragon which is unique to southern Australian waters. The Leafy is South Australia's only totally protected fish. Its beauty surpasses that of any creature found in tropical waters and, once seen by divers, is amongst the most remembered of their diving experiences. We believe that the Leafy Seadragon symbolises our Society's involvement in the marine environment.
by Philip Hall
Spotted Handfish
Handfish are small, highly unusual bottom dwelling fishes that belong to the family Brachionichthyidae.
They have modified side (pectoral and pelvic) fins that are leg-like with extremities resembling a human hand (hence their common name). Handfish are slow moving, often brightly coloured and prefer to "walk" on their pectoral and pelvic fins rather than swim.
The February 1998 (No.241) MLSSA Newsletter carries an article by David Muirhead on the subject of Handfish. He writes:
"Jim Thistleton of Western River, Kangaroo Island told me recently of a peculiar little fish he found while diving K.I.'s north coast, which by his description must have been a handfish.
Perusing the books, there are only two species recorded in S.A., the Australian Handfish and the Warty Handfish.
Handfishes are a small family of fishes, family Brachionicythidae, endemic to Australia's southern waters, notably Tasmania.
They are small, slow moving fishes with, as their name suggests, hand-like pectoral fins which they use for walking across the substrate.
They are closely related to Angler Fishes and appear to adapt well to aquaria.
They are very photogenic and I eagerly await an encounter with one of these frog-skinned denizens, which rarely exceed 10cm in length."
There are eight known species of handfish and all are found in southern Australian waters. Some of them have among the narrowest ranges of any of the 4000 marine fishes of the Australian region and are considered potentially at risk due to their small population sizes. The Ziebell's Handfish for example is only known from two localities, each only a few hectares in size.
The Australian Handfish is described as having a body which is elongated posteriorly and tapers to the caudal fin. The skin has tiny spinules, or sometimes fleshy filaments. The illicium (or rod-like portion of a luring apparatus) is long and slender with small oval esca (the bait-like portion of a luring apparatus). They are pale in colour with yellowish or orange longitudinal spots and streaks. The Australian Handfish is the most widespread species in the family and ranges from southern Queensland to South Australia and Tasmania. It is rarely seen in the shallows and is usually to be found in 40 -100 m. It can grow to 8 cm and is also known as the Prickly-skinned handfish. This species is very similar to B. hirsutas (Lacépède, 1804) which is limited to southern Tasmanian waters. Several other species are found off eastern Victoria, especially B. verrucosus (McCulloch and Waite, 1918) which is also found off the south Coast to South Australia where it is to be found in the relatively shallow Gulf waters.
Spotted Handfish are marine fish, endemic to Tasmania. Until the mid 1980s, this handfish was common throughout the areas of the lower Derwent estuary and adjoining bays near Hobart but has since declined in distribution and abundance. Majestic forests once covered this shoreline. Now it's prime real estate in the Tasmanian capital and this may be one factor in its apparent decline.
This species of handfish was first discovered by the French explorer Pe'ron and is one of the earliest Australian marine fish collected (in the late 1790s) and first described in 1804, making it among the first fish described from Australian waters. The earliest known picture of what was then called the "walking fish" was painted by convict artist William Beulow Gould around 1832.
The Spotted Handfish grows to between 100 and 150 millimetres in length. It is noted for its superb colouring of cream with yellow and black spots. They are slow moving, and recognisable individually by their unique spotted patterns.
"Walking Fish"- William Beulow Gould
Alarmingly, there have been very few confirmed records of it in recent years. The spotted handfish has just been recognised as Tasmania's only critically endangered marine fish. This is so recent that it is not yet listed under the Threatened Species Protection Act 1995. It was protected under State Fisheries Legislation in 1995. It is the first marine fish to be listed under the Federal Endangered Species Protection Act 1992 in 1996.
State and Federal lists of threatened marine fish are currently being prepared. The handfish numbers have declined so rapidly that its listing under the Federal Act was done especially.
In 1994 the Tasmanian Museum surveyed much of the Spotted Handfish's range whilst studying the introduced northern Pacific Seastar, yet only found it at one site. The CSIRO have specifically surveyed all known Spotted Handfish areas and only found a few specimens.
They are recorded as critically endangered because they have recently undergone a drastic decline in population. The cause for this decline is, as yet, unknown. Two factors are considered to be the most likely causes:
Concerns over dwindling numbers prompted the formation of a 'handfish recovery team', with representatives from CSIRO, the Tasmanian departments of Primary Industry and Fisheries and Environment and Land Management, the University of Tasmania, Environment Australia, the Hobart Ports Corporation and the Tasmanian Conservation Trust.
Research on the Spotted Handfish began with funding from Environment Australia in early 1996. So far it has involved surveys to locate remnants of former handfish populations in the Derwent Estuary, and monitoring of these colonies to study their biology and habitat, especially over the spawning season. As they move so slowly they are easy to monitor with regard to individual growth rates, movement patterns and estimates of population size and age structure. Possible biological controls and physical removal (via trapping) of the introduced seastar are being investigated. Captive husbandry techniques have also been developed in collaboration with the Tasmanian Department of Primary Industries and Fisheries at Taroona. The goals of the captive breeding program have been to gather further information on the reproductive biology of spotted handfish, as well as to provide an insurance policy should the species continue to decline in the wild, or should reintroduction be required.
A Quantum programme on the ABC on March 11th 1999 featured the Spotted Handfish and described the progress being made with regard to its study and captive breeding.
It is now known that Spotted Handfish have a low breeding capacity, the female laying only 80-250 very large eggs which are held together by threads and generally attached to the seafloor or to the stem of an ascidian. This ascidian is also one of the food sources for the Northern Pacific Seastar. The female guards the egg mass which takes six to seven weeks to hatch and is highly susceptible to disturbance. Spotted Handfish (like other handfish species) produce very few eggs for a marine fish and early life history stages have poor dispersal capabilities. This is significant as it may restrict the ability of the species to repopulate its previous range without assistance, even if the cause of the decline is removed. An artificial egg deposition surface has been developed and is being used with great success. Despite many difficulties 35 juveniles from two adult pairs have been born. The newborns liked to eat the tiny shrimp-like creatures called amphipods. This year the captive breeding program has taken off. Over 400 baby handfish have taken their first steps.
A recovery plan for these fish is also being developed. The biggest threats to the Spotted Handfish now are from illegal collectors, habitat disturbance by dredge or net fishing and from the introduced seastar. The plan suggests the following strategies:
In late June 1999, approximately 150 juvenile Handfish were released into the Derwent Estuary at an undisclosed location. These fish had been bred in captivity as part of the Recovery Plan.
Spotted Handfish
Bibliography
Acknowledgements
Spotted Handfish Picture CSIRO Webpage
"Walking Fish"- William Beulow Gould State Library of Tasmania Web Page -
Allport Library of Fine Arts
Spotted Handfish Picture Quantum, ABC, March '99
Spotted Handfish Picture CSIRO Webpage
by David Muirhead
Of stingarees and stingrays as with most fish we know little. But on the positive side (no, I'm not referring to an electric ray!) even here in SA there are relatively few known species, so in theory in-water identification should be feasible. However, many species are similar and easily misidentified and probably a significant number of species are yet to be described.
Stingarees differ from stingrays in having a caudal fin. They are often also smaller than stingrays. Stingarees and stingrays are not generally difficult to observe though doubtless many specimens partially buried in sand remain undetected by even the most observant diver. This survival tactic must be successful as it is shared by other common bottom-dwelling fish groups in our waters such as the flatheads, gurnards and stinkfishes. Like stingrays, stingarees possess venomous spines and this, coupled with their ability to swim backwards as fast as they can forwards, clearly provides opportunities for envenomation which we ignore at our peril.
As far as I can tell our stingarees and stingrays are not known to change colour pattern much during maturation from juvenile to adult. Most are grey to black and some species are known to have variable colouration and patterns as adults - for example the Western Stingaree, (Trygonoptera mucosa) can have a dorsal surface which is greyish, greyish brown or black, frequently with a few irregular scattered lighter yellowish blotches.
But how often do we actually see juveniles as opposed to apparent juveniles?
A small stingaree I photographed on a night dive in about 7m depth at Carrickalinga on 15/1/99 seemed to me to be a juvenile. It was smaller than most I've seen (disc width approx. 20cm) and had distinctive black markings below its eyes and across its back and caudal region which I had never seen before. But when I turned to the reference books for southern Australia I discovered that it was just as likely to be an adult, or nearly so, on the basis that there are several smallish species with distinctive dorsal markings somewhat similar to my specimen - namely the Cross-Back Stingaree (Urolophus cruciatus), the Banded Stingaree (Trigonoptera sp.) (not yet fully described) and the Striped Stingaree (Urolophus sp.) (also not fully described). But despite three clear photographs of the one Carrickalinga fish I have not been able to be confident of its identity. It most closely fits the description of the Striped Stingaree given in the "Sea Fishes of Southern Australia" (Hutchins and Swainston) but not only is that species said in that book to be known only from Southern WA, it is not even mentioned in the "Complete Divers and Fisherman's Guide to Coastal Fishes of South-Eastern Australia" (R. Kuiter) or the "Fishes of Australia's South Coast" (Gomman, Gover and Kuiter).
I find this uncertainty both exasperating and exciting. Usually such photographic encounters have allowed me to develop my meagre knowledge of our fish species by facilitating subsequent identification of creatures seen only briefly on dives, but this example has so far proved an exception. There is a slide of this stingaree in the MLSSA Photo Index, so if there is anyone out there…..! My curiosity is stirred. Be assured that I will be photographing all the stingarees I see from now on, although I suspect this may only lead to further confusion!
Possibly a
Striped Stingaree (Urolophus sp.)
Photographed by David Muirhead at
Carrickalinga, South Australia.
The Port River Dolphins and Their Environment
by Mike Bossley
Adelaide is probably internationally unique in being a city of a million people with dolphins living almost within the city itself.
During the past thirteen years I have been observing bottlenose dolphins in the Port River estuary and environs. Some of these animals appear to spend their entire lives within this area while many more are visitors. On any one day there are about twenty individuals in the area.
The presence of dolphins in this environment is something of a paradox. On the one hand the local marine environment is clearly subject to a range of pollutants, on the other the dolphins continue to live there.
The list of pollutants includes organochlorines (eg PCBs); heavy metals; sewage; heat effluent; and various industrial wastes.
Presumably there is a fine balance between an environment's quality and its ability to support dolphins. Unfortunately, there is no way to pinpoint exactly what this balance point is. Conditions could possibly get much worse without causing the dolphins to move or die. Alternatively, the local environmental quality might be on a knife edge from the dolphins' perspective: one more drop of pollution and they are gone. The precautionary principle must necessarily apply.
Although there is a small dolphin tourism economy at Port Adelaide, there is no doubt that the costs of stopping pollution getting into the estuary far outweigh the dollars earned from tourism. From a simple minded economic rationalism equation, ensuring the dolphins stay does not make dollar sense.
However, there is another factor, much more difficult to assign dollar values to, which must be included in the equation. Dolphins make people feel good. Almost everyone would rather live in a city which has dolphins, to one which does not. It is this quality of life factor which our government must come to terms with.
I believe that under these circumstances the best way the government can achieve environmental protection for the area is by declaring it a marine park. And what a marine park it could be!
Apart from the dolphins, the area is blessed by mangrove forests; samphire flats and some struggling sea grass beds. These provide the basis for an ecosystem supporting abundant fish and a superb diversity of bird life. Even from our limited knowledge of the estuary's wild life the city parklands and even the Adelaide Hills are desolate by comparison.
There is growing support for the concept of a marine park for the estuary at both individual and local government level. As the pressure builds the support of organisations like MLSSA will be critical to transform this support into action which will declare the park. When that time comes I hope you will lend your weight to the cause.
The Australian Dolphin Research Foundation
PO Box 572,
Magill,
SA 5072.
Ph 83903554
Acknowledgements
Port River Dolphins (2 pictures) Mike Bossley
by Steve Reynolds
Living Stromatolites
Living stromatolites are colonial reef-like structures which have been produced by photosynthesizing blue-green bacteria and other microbes. Stromatolites mostly appear as variously-sized arches, spheres or domes.
It seems that spherical-shaped stromatolites are known as Oncolites and (mound-like) cyanobacterial limestone growing on submerged trees are known as Thrombolites.
Stromatolites grow around the world but they occur in few locations. They are living a precarious existence and are nearly extinct.
Around The World
They exist in Qatar, Turkey, Mexico and America. They are also found in places such as Yellowstone National Park in Wyoming, America and Shark Bay in Western Australia. They even occur in South Australia!
South Australia
It seems that living stromatolites occur in at least a couple of South Australian locations. They are said to occur on Yorke Peninsula and also on the Jussieu Peninsula on Eyre Peninsula.
Innes National Park
Stromatolites are said to occur within the Innes National Park on Yorke Peninsula. There is a shallow salt lagoon there by the Ethel Beach turn-off. It is jokingly called Deep Lake even though it is one of the shallowest salt lagoons around and it is mostly a salt-encrusted swamp. Blue-green bacteria has apparently formed small mound-like stromatolite constructions here (thrombolites).
Sleaford Mere Conservation Park
The stromatolites on Eyre Peninsula can be seen at the Sleaford Mere Conservation Park near Port Lincoln. The Conservation Park lies at the western edge of Lincoln National Park on the Jussieu Peninsula and close to the northern shore of Sleaford Bay.
A mere is a lake and this lake used to be known as Kujabidni Lake. Kujabidni is Aboriginal for 'fishing place'. Nearby Sleaford Bay was named in 1802 by Matthew Flinders after a town in Lincolnshire, England. George Bass who discovered Bass Strait with Matthew Flinders was born near Sleaford, Lincolnshire. Sleaford is not far from Donington which is where Flinders himself was born.
Sleaford Mere is a long body of water between Sleaford Bay and Proper Bay. The mere was once a tidal inlet from the sea. Grey-black stromatolite mounds occur on the flats between the road (on the way to Cape Carnot at the tip of Eyre Peninsula) and the water.
(Cape Carnot has rocks about 2,700 million years old which were once attached to the Commonwealth Bay area of Antarctica in the ancient continent of Gondwanaland.)
When the mere was a tidal inlet, molluscs would have been able to feed on the blue-green bacteria growth but the entrance to the inlet closed when sand dunes blew across the entrance. A saline lake developed behind the sand dunes. As the water evaporated the lake became so salty that the molluscs that had been eating the bacteria could not survive there. Their death meant that the bacteria could spread unthreatened. Mats of bacteria became knitted together with fragments of limestone, sand and mud to form mounds.
Shark Bay
The dome-shaped structures in WA's Shark Bay are apparently the best example of living stromatolites. They protrude from the bay's shallow waters during low tide levels. The high temperature and salinity of the water are enough to prevent shellfish from grazing on the blue-green bacteria. These stromatolites are up to 3,000 years old.
Shark Bay - WA
Turkey
The stromatolites in Turkey are living hydromagnesite structures that occur in an alkaline freshwater lake at Salda Golu in southern Turkey. It seems that these hydromagnesite stromatolites develop on fallen tree branches in the lake.
Internet
Information about stromatolites, with pictures, is available through the Internet. Philip Hall helped me a great deal by finding articles about stromatolites on the Internet.
One of the articles that Philip found was written by Dr Ian West. It is titled "Bacteria:Fossil Record" and it discusses the Fossil Forest in Dorset, southern England in detail. (This location is also discussed later in this article.) Here are a few other things discussed by Dr West:-
The University of Wisconsin in the USA maintains a Cyanobacterial images file.
"a layered stromatolite (was) produced by the activity of . . cyanobacteria. The layers were produced as calcium carbonate precipitated over the growing mat of bacterial filaments; photosynthesis in the bacteria depleted carbon dioxide in the surrounding water, initiating the precipitation. The minerals, along with grains of sediment precipitating from the water, were then trapped within the sticky layers of mucilage that surrounds the bacterial colonies, which then continued to grow upwards through the sediment to form a new layer. As this process occurred over and over again, the layers of sediment were created."
An (untitled) article that Philip found through the Net suggests that until forty years ago (1950's) stromatolites were thought to be extinct. This changed with the discovery of the dome-shaped structures in Shark Bay.
This particular article refers to these structures as 'modern stromatolites' and "living rocks". It says that "It is now known that some (of the stromatolites) are actually comprised of living cyanobacteria that grow on top of each other at a rate of 1mm a year."
Qatar
Dr West's Internet article tells of "Very small stromatolites (thrombolites) growing on an old steel drum that has sunk into a soft sabka with hypersaline brines at Umm Said, Qatar. A hard or raised surface for attachment seems favourable for stromatolite growth."
Qatar is located on the southern shores of the Persian Gulf and adjoins the United Arab Emirates. The Persian Gulf lies between Saudi Arabia and Iran. Umm Said is on the south-east coast of Qatar.
Cyanobacteria
Blue-green bacteria are minute unicellular organisms belonging to the phylum Cyanobacteria. They used to be called blue-green alga but are really a photosynthetic bacterium because their internal structure is more like that of bacteria.
Cyanobacteria are autotrophic - they photosynthesize and their photosynthetic pigments give them the colour that gives them their name. Some, however, may be yellow, red, purple or black depending on the type of pigments that they contain.
Autotrophic means that an organism is independent of outside sources of organic substances for provision of its own organic constituents, which it can manufacture from inorganic material.
Cyanobacteria are characterized by blue-green colour due to the presence of the pigment phycocyanin distributed with chlorophyll throughout cytoplasm and masking its colour.
Prokaryotes & Eukaryotes
All living organisms fall into two major groups - prokaryotes and eukaryotes. The genetic material in eukaryotes is arranged in chromosomes contained in a fine nucleus within the cells. Prokaryotes, on the other hand, lack a nucleus and defined chromosomes.
Blue-green bacteria, like all the various bacteria, are prokaryotes (primitive organism lacking a cellular nucleus). Bacterial cells are different from those of algae, fungi and protozoans. They have a very simple internal structure and no nucleus. Bacteria do not have the chloroplasts of plants.
Algae and green plants have these small structures containing chlorophyll whereas in photosynthetic bacteria the pigment is spread throughout the contents of the cell.
The internal structure of prokaryotic cells are much simpler than that of most other cells. The various bacteria are so uniformly simple in structure that they can be classified into a group of their own (prokaryotes) and all other organisms, plant or animal, are eukaryotes.
So, animals (including humans), plants, fungi and algae are all eukaryotes (organisms with complex cells).
Earliest Life Form
Blue-green bacteria are thought to be the oldest known form of life on Earth. They are thought to have first existed about 3,500 million years ago. There are about 1500 species of blue-green bacteria.
The Earth is thought to have formed about 4,600 million years ago and there was apparently no form of life on our planet for the first one thousand million years. It is then thought that about 3,500 million years ago simple, sea-dwelling organic structures appeared on Earth (These may have formed when certain chemical molecules joined together).
Stromatolite Growth
Cyanobacteria build spongy, sediment-trapping mats which harden in layers. The sediment layers become dome-shaped layered deposits of limestone known as stromatolitic limestone, or just stromatolites.
The layered structure of stromatolitic limestone is alternate thin layers of carbonate mud and/or sand bound together by cyanobacteria as it grows upwards.
On 2/9/99 the ABC's Quantum described the procedure as:- "Sediments stick to strand-like microbes as they grow towards the light. These (sediments) leave distinct rocky layers."
No Oxygen
Past research suggested that there was no oxygen in the Earth's atmosphere when it first formed. Studies of the chemistry of rocks found no evidence of oxygen in the earliest rocks. The earliest rocks show traces of organic compounds which would have been formed by natural chemical processes.
Simple prokaryotic organisms were thought to have been the first form of life on Earth. If this was true, they were probably either unicellular or colonial organisms. They would have been anaerobic since there would not have been any oxygen in the atmosphere at the time. They would also have been heterotrophic which means (that an organism) requires a supply of organic material from its environment. The first organisms would have competed with one another for organic nutrients present in the sea.
Oxygen
Photosynthetic organisms were then thought to have appeared and that their photosynthesis caused oxygen to be released into the atmosphere. The first evidence of oxygen in the air was found in rocks approximately the same age as those found containing the earliest cyanobacteria.
Cyanobacteria were thought to have probably been responsible for the creation of the Earth's atmosphere. The initial process of photosynthesis eventually changed the composition of the Earth's atmosphere and under-pinned the subsequent evolution of life on Earth. Stromatolite colonies harness the sun's energy to take carbon dioxide from the atmosphere and release oxygen.
Cyanobacteria would have secreted oxygen into the atmosphere. The Earth's oxygen levels gradually built up over millions of years and screened out the sun's deadly ultraviolet rays. The atmosphere became breatheable oxygen and allowed the development of oxygen-breathing organisms. This allowed the first advanced life forms to evolve on Earth.
|
CHART 1, GEOLOGICAL TIME SCALE |
|||
|
AEON |
ERA |
PERIOD |
YEARS AGO |
|
Cryptozoic or Precambrian |
Archaezoic |
|
2600-4600m |
|
Cryptozoic or Precambrian |
Proterozoic |
|
570-2600m |
|
Phanerozoic |
Palaeozoic |
Cambrian |
510-570m |
|
Phanerozoic |
Palaeozoic |
Ordovician |
439-510m |
|
Phanerozoic |
Palaeozoic |
Silurian |
409-439m |
|
Phanerozoic |
Palaeozoic |
Devonian |
363-409m |
|
Phanerozoic |
Palaeozoic |
Carboniferous |
290-363m |
|
Phanerozoic |
Palaeozoic |
Permian |
245-290m |
|
Phanerozoic |
Mesozoic |
Triassic |
208-245m |
|
Phanerozoic |
Mesozoic |
Jurassic |
146-208m |
|
Phanerozoic |
Mesozoic |
Cretaceous |
65-146m |
|
Phanerozoic |
Cainozoic/Cenozoic |
|
0-65m |
Fossils
Fossilised stromatolites are said to be the oldest known fossils. An untitled article from the Internet suggests that these colonial structures date "back more than 3 billion (American) years" (3,000 million years).
Pisolites
Dr Ian West's article refers to "small concentrically layered structures called pisolites". It says that these "pisolites are also the result of fossilised bacteria".
Layers & Domes
Cyanobacteria lived in huge masses that could form floating mats or extensive reefs. Masses on the sea floor deposited calcium carbonate in layers or domes. These layered deposits are known as laminar stromatolites. Such layered stromatolites are found in Precambrian rock in the Ozark Mountains in Arkansas, America. These are laminar stromatolites known as Ozarkcollenia. This is a distinctive type of layered Precambrian stromatolite which places the appearance of life in the area to well over 1,500 million years ago.
W.A. Fossils
The oldest stromatolite fossils yet dated occur in Western Australia in Precambrian rocks.
The Precambrian Age is also known as the Cryptozoic Aeon. This was the whole period preceding the Phanerozoic Aeon (Evident Life) which includes the Palaeozoic Era (Ancient Life) - see Chart 1.
The stromatolite fossils in WA were discovered in 1978 by a graduate student who was doing some geological mapping in the Pilbara district (near Port Hedland). Palaeontologists (fossil experts) thought that they (the fossils) were about 3,500 million years old. The oldest rocks, at 3,800 million years old, are only a little older than the stromatolite fossils which the palaeontologists believed to be the earliest evidence of life on Earth.
Microscopic Algae
Australian scientists now claim to have discovered chemical traces of microscopic algae dating back 2.7 billion years. (The 2.7 billion must be American billions, thousand millions (2,700 million). English (and Australian) billions are million millions.)
The chemical traces were found in rocks from the Pilbara region in WA. A report in The Advertiser of 13th August 1999 gives details of Australian research published in that day's publication of the journal "Science". It said that a team of researchers at the University of Sydney in conjunction with the Australian Geological Survey Organisation had made a remarkable discovery. Rocks from the Pilbara region had turned up chemical traces thought to be from microscopic algae dating back 2.7 billion (American?) years. This will undoubtedly shake up all studies of biology, chemistry and geology around the world.
Magnetite Crystals
Dr West's article "Bacteria:Fossil record" refers to crystals formed by microscopic bacteria (not algae) that have been found in rocks as old as two billion (American?) years. He says that "magnetobacteria . . form tiny nanometer-sized crystals of magnetite (iron oxide) inside their cells. Magnetite crystals identifiable as bacterial products have been found in rocks as old as two billion years."
He says that "the fossils left by magnetobacteria . . at a size of a few hundred millionths of a metre, . . hold the record for the smallest fossils."
Archaean Algae
Remember that all algae are eukaryotes with complex cells. Eukaryotes were previously thought to have evolved during the Proterozoic period. The new discovery pushes their evolvement back to the Archaean period. This was the earliest part of geological time.
A PhD student at the University of Sydney devised and conducted experiments over a year ago that disproved the theory that eukaryotes stemmed from the Proterozoic period. He discovered molecules that included derivatives of cholesterol and steroid molecules (which are both eukaryote?). The source of the discovery were rocks from the Hamersley Range in the remote Pilbara region of WA. It seems that these rocks (or the molecules) have been dated as being 2.7 billion (American) years old (2,700 million years).
Quantum
According to "Biological Science - the web of life", stromatolite fossils 3,500 million years old were found in WA's Pilbara region in 1978 (Part 2, page 879). The ABC's Quantum on 2/9/99, however, gave the impression that such fossils were a recent find. Dr Kath Grey was credited with the discovery of stromatolite fossils in the Pilbara region. Experts from around the world visited the location to determine whether or not the fossils were in fact stromatolites.
There were at least six professors who studied the fossils and they seemed to agree that the fossils were those of stromatolites. Three of the professors came from the University of California at Santa Barbara, Los Angeles. Another one was from Arizona State University.
Fossil Theft
Whilst the various experts studied and photographed the fossils, Kath Grey realised that some of her discoveries were missing. It seems that some of the fossils had been stolen earlier. Fossil theft had been a problem in recent times. The experts decided to carefully remove all of the fossils and replace them with imitation ones. This regrettable action was necessary because of a few greedy people.
Bitter Springs
"Bacteria:Fossil Record", the Internet article by Dr Ian West says that ancient fossilised cyanobacteria is found at the Bitter Springs chert in central Australia. Chert is an impure granular variety of cryptocrystalline quartz. Bitter Springs Creek is in the Northern Territory near the Ross River Tourist Centre. The area is (relatively) close to Alice Springs. The site dates to the Late Proterozoic, about 850 million years old.
Flinders Ranges
Stromatolite fossils also occur in the Flinders Ranges in South Australia. Details are given in a pamphlet about the geology of the Flinders Ranges National Park issued by The Department of Mines & Energy. The Pamphlet is titled "Corridors Through Time".
According to the pamphlet, stromatolite fossils have been found in the Trezona Range in Brachina Gorge. The fossils can be seen as faint outlines and ridges in Precambrian limestone rocks.
The pamphlet includes a map of the National Park showing Brachina Gorge and the Trezona Range. There is an aerial map of Brachina Gorge on the front cover. There are drawings of stromatolite fossils in the pamphlet along with some information about them. About 3,500 million years ago mats of cyanobacteria piled up as layers and became stromatolite domes in shallow water along the edges of the Adelaide Geosyncline (Which will be explained in an future Newsletter article). As marine animals evolved they began to feed on the mats causing stromatolites to become almost extinct.
Web Of Life
The book "Biological Science - the web of life" gives the following details about stromatolites fossils:-
"One of the most common types of fossils in Precambrian sediments are branching or dome-shaped, layered deposits of carbonate, called stromatolites, which are thought to have been produced during past ages by blue-green bacteria. They were so abundant in primitive seas that they formed reef-like structures up to several hundred metres thick. These reefs were of a size comparable to the present day reefs produced by coelenterate polyps."
Evolution
More complex types of algae appeared later in the Precambrian Age. Multicellular soft-bodied animals such as worms and jellyfish appeared towards the end of the Aeon. Shelled invertebrates such as trilobites (bottom-dwelling arthropods) appeared in the Palaeozoic Era, during the Cambrian Period. Marine plants flourished during the Ordovician Period and coral reefs also appeared. Land plants appeared during the Silurian Period. Vertebrates and amphibians appeared during the Devonian Period. Trees appeared during the Carboniferous Period and coal-forming forests flourished. Conifers appeared during the Permian Period.
The Fossil Forest
Stromatolitic limestone is found in Dorset in southern England, in the Fossil Forest. The forest is a limestone ledge in the cliff near Lulworth Cove, Dorset. There are interesting stromatolites and the remains and moulds of coniferous trees from either the late Jurassic or early Cretaceous periods - see Chart 1.
The coniferous trees are rooted in a palaesol (the Great Dirt Bed). Stromatolitic limestone is found above the trees and a limestone breccia is above the stromatolitic limestone. Breccia is clastic sedimentary rock consisting of angular fragments cemented together in a matrix.
The Coorong
The article "Bacteria:Fossil Record" by Dr Ian West (sourced from the Internet) compares South Australia's Coorong with the Fossil Forest. The forest "is excellent because it shows numerous moulds of fossil trees surrounded by stromatolitic limestone". The Purbeck Formation is referred to in the article which goes on to say that "the Coorong, and other South Australia (sic) areas are useful guides to the Purbeck palaeoenvironments".
Archaean Period & Proterozoic Era
The article also says that "In some cases, the stromatolites were infiltrated with a mineral-rich solution which fossilised the bacteria along with the layers, but more often only the layers are preserved. The oldest stromatolites date to the Early Archaean, and they became abundant by the end of the Archaean. In the Proterozoic, stromatolites were widespread . . By the close of the Proterozoic, the abundance of stromatolites decreased markedly . ."
Stromatolites In The Fossil Forest
Dr West's article details the occurrence of stromatolites in the Fossil Forest area. He says that "Stromatolites with hollow moulds which once contained trees are also visible in the north face on the west side of the Durdle Door promontory".
"Some stromatolites (can still be seen) at Potters' Hole".
"The Hard Cap of fine-grained, lagoonal oolitic and pelletal limestone contains large ovoid stromatolites. The Great Dirt Bed is well exposed and above this comes the Soft Cap with some stromatolite limestone. Half of a stromatolite mound above a tree is visible at present."
"The lower part of the Soft Cap above consists of stromatolitic limestone formed in shallow hypersaline water."
"……the Fossil Forest section is important in showing …… good stromatolites".
('Oolitic' refers to the texture of limestone resembling the mass of eggs seen in fish-roe. It comes from the Greek word for egg which is either 'oon' or 'oion'. The Oolitic and Liassic (epochs?) both belong to the Jurassic Period.)
Mexico
Another article sourced from the Internet about stromatolites is titled "Cuatro Cienegas (sic) Stromatolites" (Cuatrocienagas de Carranza). It is all about Mexican stromatolites (estromatolitos). It says that "There are three different types of stromatolites in Cuatrocienagas. Stromatolites are formed by either cyanobacteria, diatoms or bacteria". It then goes on to describe numerous examples of the three types occurring at different sites in Cuatrocienagas.
Cuatrocienagas de Carranza is in the Mexican State Coahuila which is on the Mexican border next to Texas, USA.
Stromatolites are said to occur at Rancho Quintero, Pozo Azul there (in Cuatrocienagas). These stromatolites apparently show "variations in colour due to the presence of different algae and bacteria at different distances inward from the surface of the structure".
These stromatolites are apparently located in water, forming at a depth of half a metre. They are delicate and several have been damaged by people stepping on them.
Toxic Bacteria
Various forms of blue-green bacteria can produce toxins which are deadly to fish. There has been an increased incidence of toxic blooms in Australia due to high nutrient run-off. Polluted run-off is causing increased eutrophication of waterways and is threatening fisheries and water quality.
(Whilst writing this article I have had to research lots of words and places that were new to me. I have done my best with words such as oncolites, pisolites and thrombolites and locations such as Bitter Springs, Umm Said and Salda Golu. Words arose that I couldn't research in the time available. Words like charophyte, celestite and pelsparite. Perhaps these could be the basis of another article!)
References:
"The World Down Under", Australia Post, 1995.
"Biological Science - the web of life", Australian Academy of Science, 3rd edition 1981.
"Steve Parish Amazing Facts About Australian Marine Life - Discover and Learn, Volume 6", Text by Pat Slater, Steve Parish Publishing, 1997.
"Ultimate Visual Dictionary" published by RD Press (Reader's Digest) 1994.
"A Dictionary of Biology", Abercrombie, Hickman & Johnson, Penguin Books, 1964.
"Corridors Through Time", a pamphlet about the geology of the Flinders Ranges National Park, Department of Mines and Energy.
"Philip's Atlas of the Oceans", John Pernetta, Philip's, 1994.
"Fodor's USA 1999", edited by A.McConnell & M.Lore, Fodor's Travel Publications, 1998.
"Matthew Flinders" by Thea Stanley Hughes, 1991, Movement Publications.
"Touring the Eyre Peninsula", RAA of SA, 1984.
"Mid North and Yorke Peninsula" by Stuart Nicol, 1990, RAA of SA.
"The Adelaide Geosyncline" by Steve Reynolds, MLSSA Journal No.10, December 1999.
"Bacteria:Fossil Record" by Dr Ian West on the Internet.
"Cuatro Cienegas Stromatolites" by Barbara Winsborough? on the Internet.
ABC's Quantum programme 2/9/99.
(Many thanks to Philip Hall for his encouragement and assistance with information from the Internet.)
Acknowledgement
Stromatolites (WA) Barbara Winsburgh
Courtesy Western Australia Tourist Department
by Philip Hall
Beachwatch is an environmental campaign to monitor litter on Britain's beaches, raise awareness of the issue of marine debris and encourage action to reduce marine pollution at source.
The Beachwatch campaign is organised by the Marine Conservation Society with sponsorship from Reader's Digest and is part of the International Coastal Cleanup co-ordinated by the Center for Marine Conservation in the USA.
Beachwatch is a national beach litter survey and clean up in September involving thousands of volunteers. Each survey provides a snapshot of the amounts and types of marine litter on British beaches and, with continued monitoring, a better picture of the problem and trends over time can be built up. Beachwatch data is used to identify the major polluters and form recommendations for action that will reduce the sources of marine and beach litter.
Marine litter, ranging from plastic bottles, sanitary towels, and crisp packets to strapping bands, fishing line and nets, spoils our beaches and pollutes our oceans. But it is more than just a litter problem, marine debris kills wildlife from birds to dolphins, poses a health risk to beach visitors and harms local economies through ghost fishing, lost tourism revenue and repeated cleanup costs.
Marine litter comes from many sources including sewage discharges, illegal dumping by ships, direct littering by tourists, discarded waste from fishing vessels and litter carried to sea by rivers and streams.
Although there are many pieces of legislation in place which are aimed at reducing this pollution, effective implementation and enforcement is slow.
By involving members of the public in the Reader's Digest Beachwatch campaign, understanding of the issue is raised and people are able constructively to express their concern for the environment and their desire to see action taken to prevent marine pollution.
Top Twenty items found during Reader's Digest Beachwatch '98
Chart 1
1 Plastic pieces 1 cm 32,848 10.2 197.1
2 Rope/cord 29,879 9.3 179.3
3 Caps/lids 20,341 6.3 122.0
4 Polystyrene pieces 17,700 5.5 106.2
5 Crisp/sweet packets 17,213 5.3 103.3
6 Glass pieces 17,069 5.3 102.4
7 Cotton bud sticks 16,840 5.2 101.0
8 Plastic pieces < 1 cm 16,445 5.1 98.7
9 Plastic bottles - Drinks 13,380 4.1 80.3
10 Cigarette stubs 12,078 3.7 72.5
11Cutlery/trays/straws 9,587 3.0 57.5
12Drinks cans 8,434 2.6 50.6
Top 12 items 211,814 65.6 1,270.9
13Paper pieces 8,061 2.5 48.4
14Plastic bags 7,670 2.4 46.0
15Fishing line 6,381 2.0 38.3
16Wood pieces 6,047 1.9 36.3
17Fishing net 5,123 1.6 30.7
18Metal Bottle caps 3,443 1.1 20.7
19Towels/panty liners 3,422 1.1 20.5
20Metal pieces 3,369 1.0 20.2
Top 20 items 255,330 79.1 1,532.0
Litter Plastic is the most prevalent debris material and has consistently amounted to over 50% of all litter recorded, and the percentage recorded in Beachwatch '98 (57%) matches that recorded in Beachwatch '97 ('97 - 57%; '96 - 52%; '95 - 53%; '94 - 54%).
The most common 12 items of litter made up 66% of the total item count, comparable to the 65% recorded in Beachwatch '97, and the top six items, plastic pieces 1 cm, rope & cord, plastic caps & lids, polystyrene pieces, crisp & sweet wrappers and glass pieces, represented 42% of the total items recorded.
Regional breakdown of the sources of litter recorded in Beachwatch '98
Chart 2
Source C. I. England N. I. Scotland Wales
Tourist/
No of items 3,242 75,247 10,654 16,871 12,471Fishing
No of items 1,983 26,438 1,259 7,827 5,915Sewage
No of items 63 16,621 1,125 3,320 2,717Shipping/
No of items 345 5,170 496 1,843 1,660Fly-tipped
No of items 280 2,097 1,104 495 259Medical
No of items 2 170 8 86 28Non-sourced
No of items 4,350 78,112 5,774 15,545 19,174Total items
10,265 203,855 20,420 45,987 42,224Mean items/km
1,242.0 1,806.1 1,819.3 2,713.7 2,431.9No. beaches surveyed
24 144 12 35 42Length surveyed (km)
8.3 112.9 11.2 16.9 17.4LEGEND
C.I. = Channel Islands
N.I. = Northern Ireland
The highest levels of litter within the UK were recorded in Scotland, with a mean of 2,714 items per km surveyed; in Wales 2,432 items per km surveyed were recorded; Northern Ireland recorded 1,819/km; England recorded 1,806/km and the Channel Islands 1,242/km.
Within each region, tourist and recreational litter was the most common source of litter recorded: Northern Ireland - 52% ('97 - 54.8%), Scotland - 37% ('97 - 34.8%), England - 37% ('97 - 33.9%), the Channel Islands - 32% ('97 - 37.7%), and Wales - 29% ('97 - 32.3%).
Scotland recorded the highest levels of litter overall (2,714/km), including the highest levels of fishing debris (462/km), sewage related debris (196/km), shipping waste (109/km) and medical waste (5/km). Northern Ireland recorded the highest levels of fly-tipped waste (98/km), but the lowest levels of fishing debris (112/km).
The Channel Islands recorded the lowest levels of litter overall (1,242/km) and the lowest levels of tourist litter (392/km), sewage related debris (7.6/km) and shipping waste (42/km).
Sources of litter found during Reader's Digest Beachwatch '98
Chart 3
Source No of Items % age Items/km
Tourist 118,485 36.7 710.9
Fishing 43,422 13.5 260.5
SRD 23,846 7.4 143.1
Shipping 9,514 2.9 57.1
Fly-tipped 4,235 1.3 25.4
Medical 294 0.1 1.8
Non-sourced 122,955 38.1 737.7
Total 322,751 1,936.5
The four major sources of beach litter as identified by Reader's Digest Beachwatch are: tourist and recreational inputs (36.7%), fishing (13.5%), sewage related debris (SRD) (7.4%) and shipping/galley waste (2.9%). Together, these four major sources comprise over 60% of all litter found.
Apart from the figures for SRD, the values attributed to other sources are underestimates, as each will be responsible for a proportion of the items placed in the non-sourced category.
Beachwatch Litter Trends
Chart4
(If this chart is in black/grey/white then read the dates as starting from the left along the bottom axis in each group, ie 1994
® 1998.)The Beachwatch '98 results show a 24% increase in the number of items recorded per kilometre surveyed as compared with Beachwatch '97. Levels of litter recorded have almost doubled since Beachwatch '94. 1,936 items per km surveyed were recorded in Beachwatch '98 compared with
1,554 items per km surveyed in Beachwatch '97;
1,482 items per km surveyed in Beachwatch '96;
1,654 items per km recorded in Beachwatch '95 and 1,045 per km surveyed in Beachwatch '94.
Recommendations
Reduction of the Input of Litter from
Land-Based Sources:
Reduction of Pollution from Ships and Fishing Vessels:
Reduction of the Input of Sewage Related Debris:
Individual responsibility:
Reduce
Reuse
Recycle
Bibliography
This article is published
with the permission of the
British Marine Life Study Society.
by Chris Hall
It was my last St Patrick's Day living in Ireland and we had decided some days before hand to go down to Dingle in County Kerry to dive with a wild dolphin. This had been organised by the Army Sub-Aqua Group which I sometimes dived with. I was employed by the Department of Defence and worked for the Irish Army Air Corps as a civilian technician.
The day after St Patrick's Day we commenced our 150 mile trip from Dublin to Tralee. Tralee is quite famous for its Rose of Tralee Festival and boasts about 33 pubs for a small population.
We arrived in Tralee some 4½ hours later. The roads in Ireland are quite slow except for main highways. Often you can encounter two farmers moving cattle from one field to another, stopping to have a chat in the middle of the road. Time doesn't exist for these farmers as they pass the time of day discussing the weather, price of milk and any other local gossip. Anyway, despite these interruptions we made it.
Having arrived in Tralee we had to organise some accommodation. The army guys were OK, they had the Army Reserve Barracks to stay in, but being a civilian I was a bit of a problem. However, they managed to smuggle me in and I managed to keep a low profile for the two days, which wasn't easy being bearded and having an Aussie accent.
Next day we were off to Dingle where we were to encounter Fungi a wild dolphin who had been popularised by two local divers and a BBC documentary.
Fungi
On arrival at Dingle we were disappointed with the conditions. It wasn't raining which was quite surprising as it rains 5 days in 7 down there. The problem was the state of the sea, choppy and poor visibility. A quick discussion ensued and it was decided that it was too dirty to dive but we'd try snorkeling. We launched the inflatable and headed out into the bay.
After half an hour or so of being bounced around and nearly frozen to death, (March winds in Ireland can be deathly cold) to our great excitement and joy we saw a dorsal fin approaching from about 100 yards. We quickly kitted up and jumped into the water and nearly froze. The water temperature was about 9°C.
Numbed from the cold we snorkeled to where we thought the dolphin might appear. Then the thrill of a lifetime. I don't think I'll ever forget this experience for the whole of my life. I was contemplating getting out of the water when suddenly from nowhere Fungi appeared from under me and surfaced. I stretched out an arm and found to my surprise my hand had caught his dorsal fin and I was being given a free ride through the water. I reached down with my other arm and started to stroke his side, he rolled over like a dog and let me rub his belly. I will never forget the look in his eye, so loving and intelligent, a once in a lifetime experience. Too soon it was all over but my first encounter with a wild dolphin in his environment will remain the greatest thrill of my life. To end a great day as we were leaving in the boat Fungi leapt right over the bow of the inflatable, a fitting goodbye to a marvellous encounter as a parting gesture.
Fungi
My second encounter with wild dolphins occurred here in Australia snorkeling off Glenelg beach. Some years ago when I was slimmer and fitter I used to go out to the Blocks snorkeling from Glenelg beach.
It was on one of these sojourns into the marine world that I encountered four dolphins, three adults and one baby. I had seen them when level with the end of the jetty but two or three hundred metres south. I decided to snorkel towards them and to my surprise they changed course to investigate this intruder in their domain.
The three adults didn't pay too much notice of me but the baby wanted to play. I dived down to get closer and from this ensued a game of chasey and tag with the baby. It would swim up under me and spiral away, daring me to catch it. Unfortunately I couldn't. I've yet to gain the prowess of a dolphin in water. After about 20 minutes the baby got bored with my inadequate efforts at tag and disappeared with its escort into the deep blue, thinking these humans aren't much fun, they can't even keep up.
I guess I've got a few years diving left in me yet but if I never have any further close encounters with wild dolphins, I can consider myself extremely lucky for my experiences.
Acknowledgements
Fungi (From "Falling for a Dolphin") Sheila Stokes
Heathcote Williams(Author)
by
Sharon L. DrabschBottom trawling to harvest species such as prawns has an incontestable impact on the marine benthos as the trawling equipment scrapes along and ploughs into the seabed (Engel and Kvitek, 1998; Hall, 1999). Studies have found that bottom trawling removes, kills and damages a great number and variety of benthic species. It also physically alters the substrate and resuspends sediment, which has follow-on implications for the biota (Jones, 1992). Despite this, the extent and intensity of this type of fishing practice has continued to grow. This has resulted in increasing concern from public and political groups as well as the fishing industry itself. The concerns centre around the effect of trawling on fisheries, non-target species and entire biological communities (Hall, 1999). The amount of damage caused by trawling depends on the weight and towing speed of the trawl gear, which have both increased substantially over the past two decades (Bergman and Hup, 1992, van Beek et al. in Hall, 1999). The type of substrate and biological community also influences the amount of damage incurred. Recovery rates vary, depending on the damage inflicted, the type of community and substrate, and the hydrodynamics of the environment.
It is well known that the level of endemism and diversity for many marine taxa is very high in the waters of southern Australia. In addition, the gulfs of South Australia are unusually shallow and hypersaline basins. (Hutchings et al., 1993; Bye, 1976). Thus, the gulfs of South Australia support distinctive biological communities. However, these gulfs are also important fishery grounds for a number of target species including prawns.
While the effects of trawling has been investigated in other areas of the world where trawling effort is significant such as the North Sea, such a study has not been conducted in South Australia.
The aim of this project is to research the impact that prawn trawling, of the type undertaken commercially in the region, has on the macroinfaunal soft-sediment communities in Gulf St. Vincent. Macroinfauna refers to animals greater than 0.5mm that live within the sea-floor sediment. Macroinfauna are an important component of the marine biota and studies suggest that they are also good indicators of disturbance. In addition, they are conducive to (and popular for) studies that investigate environmental impacts for a number of reasons. They are relatively sedentary and therefore useful for studying local effects, they can be sampled quantitatively, and their coarse taxonomy fairly easily determined (Warwick, 1993). However, studies of infauna have been found to have some inherent complications. As shown by the two studies of Morisey et al. (1992), these communities exhibit natural spatial and temporal variability over many different scales. This has the potential to confound results of impact studies. However, an experimental design that incorporates adequate replication on a number of scales should overcome this problem.
Western King Prawn
Experimental Design
The project will be run in conjunction with a study being conducted by Dr. Jason Tanner from the South Australian Research and Development Institute (SARDI), Aquatic Sciences Division, who will be investigating the impact that such trawling has on epifauna. Epifauna refers to benthic animals that live on the substrate surface. The research design is "multiple before-after, control-impact" (MBACI). There will be three locations, and a control (untrawled) and impact (trawled) site within each location. These locations will be in north-central Gulf St. Vincent in about 20m water depth. Near the centre of each site a 50m transect will be laid out and three 2x1m quadrats placed at random along, and within 5m perpendicular to, the transect. The quadrats will be permanently marked with steel pegs, driven into the substrate (below the substrate surface at the sites to be trawled). Coloured tape, marked with reference numbers for the quadrat and peg will be attached to the pegs to assist in the precise relocation and identification of the quadrats. Core samples of the substrate will be taken by SCUBA divers with 40mm diameter PVC pipe, to a depth of 150mm, both before and after trawling. If time permits, samples will also be taken 3 months after the post-trawl sampling in order to investigate recovery. Ten replicate cores (plus one for sediment analysis) will be taken from each quadrat. In addition, ten air-lifted suction samples will be taken remotely at each site. Samples will be fixed with 10% Formalin and buffered with Borax. The sampling will be conducted in 6-7 day blocks on the SARDI Research Vessel "Ngerin". The trawling will be performed by a commercial otter-type trawler.
In the laboratory, the samples will be sieved through a stack of 2, 1 and 0.5mm sieves, with the retained fractions then sorted in water. Fauna will be identified to a coarse taxonomic level, then preserved in 70% alcohol. A number of papers, including Warwick (1993) have indicated that coarse taxonomic levels are acceptable, even recommended, for benthic organisms, as disturbance effects are at least as evident and sometimes more so, at the highest taxonomic levels. Thus a high level of expertise is not needed, and identification is quicker. Particle size analysis may be conducted on cores taken from each site.
Analyses
I am looking for a statistical interaction between trawling and the community composition (the number of taxa and individuals) of the macroinfauna. This will be achieved by multivariate analysis. The community composition of all the sites before trawling will be compared with that of the impact sites after trawling, and the control sites will be compared with the impact sites after trawling. I expect to find that the community composition at the impact sites after trawling has diverged from that of the sites before trawling and from that of the control sites after trawling.
References
Bergman, M. J. N. and Hup, M. (1992). Direct effects of beam trawling on macroinfauna in a sandy sediment in the southern North Sea. ICES Journal of Marine Science 49, 5-11.
Bye, J. A. T. (1976). Physical oceanography of the Gulf St. Vincent and Investigator Strait. Pp143-160. In 'Natural History of the Adelaide Region.' (Eds. C. R. Twidale, M. J. Tyler and B. P. Webb) (Royal Society of South Australia: South Australia).
Engel, J. and Kvitek, R. (1998). Effects of otter trawling on a benthic community in Monterey Bay National Marine Sanctuary. Conservation Biology12(6) 1204-14.
Hall, S. J. (1999). 'The Effects of Fishing on Marine Ecosystems and Communities.' Blackwell Science: Oxford
Hutchings, P.A., Ward, T.J., Waterhouse, J.H. and Walker, N.C. (1993). Infauna of marine sediments and seagrass beds of Upper Spencer Gulf near Port Pirie, South Australia. Transactions of the Royal Society of South Australia, 117(1), 1-15.
Jones, J. B. (1992). Environmental impact of trawling on the seabed: a review. New Zealand Journal of Marine and Freshwater Research, 26, 59-67.
Morrisey, D.J., Howitt, L., Underwood, A.J. and Stark (1992). Spatial variation in soft-sediment benthos. Marine Progress Series, 81, 197-204
Morrisey, D.J., Underwood, A.J., Howitt, L. and Stark, J.S.(1992). Temporal variation in soft-sediment benthos. Journal of Experimental Marine Biology and Ecology, 164, 233-246.
Warwick, R.M. (1993). Environmental impact studies on marine communities: pragmatical considerations. Australian Journal of Ecology, 18, 63-80.
--------------------------------------------------
Timetable
6-11 Aug. First pre-trawl Ngerin cruise
23-30 Aug. Second pre-trawl Ngerin cruise
early Oct. Trawling undertaken by commercial vessel
18-23 Oct. First post-trawl Ngerin cruise
4-9 Jan. Second post-trawl Ngerin cruise (if time permits)
8 May Paper due
Acknowledgement
Western King Prawn David Muirhead
The Effects of Trawling In South Australia's Gulfs
by Ralph Richardson
Introduction
How many of South Australia's recreational divers would go to the centre of St Vincent Gulf to dive on a random path of featureless sea-bottom? With the exception of those who look for, but fail to find the Zanoni wreck, I suspect the answer is - not many. In August this year I had the opportunity to spend a week diving in Gulf St Vincent. Although not expecting the normal tourist style diving sites, I looked forward to observing the biodiversity at the centre of the Gulf.
I have previously dived more than 150 times in South Australian waters, in locations ranging from the Victorian border to Port Lincoln. I am nearly always overwhelmed by the variety of life, even in what could be considered the more barren sites. Regarding fish, it would not be uncommon to see 40 to 50 species on a single dive, and nearly always a different variety of species at each location on subsequent dives. Even two relatively close sites, perhaps within a kilometre, would vary greatly in fish life. I can honestly say that nearly every dive yields something I have not seen before. I mention this simply because it is in such strong contrast to what I observed in the centre of Gulf St Vincent.
Over eight days, I got to dive a total of ten times, ranging over three locations. During these ten dives I recognised every fish I saw, and I only saw ten species. Actually I only saw six species while diving; three I saw at the surface and one was brought up from the bottom at night.
The one species that truly dominated this domain is the Degens Leatherjacket. This species outnumbered others by orders of magnitude. The only other fish to be seen in any number were Wavy Grubfish and Jumping Blennies. I saw a total of four Silverbellies, a Threefin and a Smalltooth Flounder. These fish were all seen on the bottom during the day time. The surface often had large clumps of seagrass floating past and in this I noticed a couple of Spotted Pipefish. At night I saw the fish that interested me the most. Floating amongst the seagrass was a juvenile Short Boarfish. This fish would lie on its side, raising its fins as I approached it so that it resembled a piece of the seaweed. Also at night Garfish could easily be seen to be attracted by the light of the boat. A Goat Fish was brought up from the bottom in a trap.
The bottom was at about 20 metres at all three dive locations. The one outstanding feature was the lack of any features. The bottom was very flat.
The first site sediment was a mixture of medium coarse grains, silt and shell fragments. Although the light levels were fairly low at this depth, the seagrass "Halophila" was growing, albeit sparsely.
The second site was mud like thick silt. Someone suggested the "mud" was particle fallout from the Bolivar sewage works, settling out in the quieter waters in the centre of the Gulf. I have no idea if there is any truth to that, but I believe that anyone who came in contact with the bottom could easily come to that conclusion. Filamentous algae was growing over the sediment.
The third site had a much coarser sediment.
The sediment at third site, in many places, was only about 10 to 15 cm thick, beneath which lay a very solid foundation of calcrete.
Invertebrate life on the bottom was sparse and consisted predominantly of Razorfish, especially at the second (the muddy) site, although scallops were not uncommon. There were no other noticeable forms of molluscs. I saw one or two starfish per dive, but they were not large and did not appear to have any dominance in the environment. Some larger specimens included solitary ascidians, a sea-cucumber, a large worm and a very impressive sea-pen.
By far the most impressive life forms on the bottom weren't very large, and in fact they weren't quite on the bottom. Living on the razorfish was an assortment of spectacular sponges, ascidians, bryozoans and hard corals. All of the razorfish at the second site were covered with this beautiful epifaunal community. This growth would often span two or more razorfish and in many cases across large numbers, looking something like brightly coloured houses on stilts.
The Effects of Trawling
I caught three red crabs in a baited fish trap one night but another crustacean that lives on the bottom forms the focus for this story. On a dive on the second site I noticed a pair of eyes poking out of the mud. I could also see a bright blue tail, the tail of the Western King Prawn. The only other prawn I saw on the whole trip were two juveniles brought up from the bottom in the trap.
South Australia is in the middle of the worlds' most biodiverse marine region and yet the centre of the Gulf has the least diversity of any area I have ever dived. So is the lack of fish diversity natural or have the other fish just left, and if so where and why did the fish go? No, this lack of diversity is not natural. To look at this, let's go back to 1968. I am adding in an extract from Ben Simms' book "The End of a Gulf Fishery". Ben was a 4th generation fisherman born at Moonta and had fished SA waters since 1944.
"The first fifteen years on the Mary Anne Simms', (1958-1973), would have seen the best of all the schnapper fishing in the gulf, right up to the beginning of the decline brought about by the advent of the prawn fishery.
In 1968, a mate of mine from Pt. Lincoln, Roger Howlett, came up the gulf looking for prawns. We had a talk about it and I offered to show him some likely places to try.
Now all my fishing life I have caught schnapper with prawns in their guts, have caught big schnapper plenty of times that have spewed live prawns on the deck upon landing - mostly down the gulf, east and west of what we called the 'gutter'. It was here I directed Roger to 'have a go'. He was successful on the first night with a good catch. After that my brother Barry rigged `Liteva' for prawns, as did two other boats from Pt. Lincoln, 'Collega' and 'Suzannah'. Then I put gear on the 'Mary Ann'. We trial and erred for a while but we caught prawns. I still fished for schnapper, however, and only prawned on good nights.
The success of this latest fishery soon brought ruthless fishermen from Pt. Lincoln to the gulf, to tear up the bottom from one end to the other. It's laughable when they say that you can only pull a certain amount of razor fish up out of the shallows, when this armada of big boats were tearing up thousands of tons of them, out in the deep water. Not only in the gutter, but these boats went north, over virgin bottom, all over the top end of the Gulf. They also killed the leatherjackets, small trevally, squid, and crabs; shellfish by the ton, every night. They also tore up the tape weed and killed the sponge life; all part of the food chain of our scale fish."
The area in which I was diving was somewhat unusual for our Gulf waters, as it had not been trawled for more than a decade. As a recreational diver, I tend to take great care not to damage things like corals and bryozoans. In this case, I needn't have bothered. These areas have since been retrawled after I dived them.
Bottom trawling gear scrapes along and digs into the sea floor and ploughs up to about 5cm into soft sediment, so any epiflora/flora (organisms that live on the sea-floor) and some infauna (animals that live within the sediment) such as razorfish and colonial life forms get smashed to pieces. Trawling brings up as much as twenty times as much incidental catch (bycatch) as compared to the target species. 90% of the bycatch dies. Of those that make it to the surface, nearly all perish on the boat or soon after it has been discarded over the side. Any ray which manages to survive being brought up from the bottom will have its tail chopped off by those sorting the prawns, for fear of it causing injury.
With the exception of squid and Balmain Bugs (Slipper Lobsters), all of the bycatch brought up with the prawns is discarded. Blue swimmer crabs are one of the few species which may survive intact; but although a commercial South Australian fishery they are discarded on prawn trawlers because the trawling licence doesn't cover crabs. Many commercial species of finfish are also trawled up but these too have to be discarded although most die.
The trawling at these sites brings up great numbers of the fish species I mentioned earlier, but also many others. Some of these others include Whiting, Cowfish, Pygmy Leatherjackets, Fiddler Rays, Stingrays, Flounder, Gurnard Perch, Porcupine Fish, Toadfish, Cardinalfish and various Scorpionfish. Many invertebrates are also brought up, including Brittle Stars and Hermit, Spider and Sponge Crabs.
So how much area are we talking about being affected here? These were experimental trawl corridors about 200m wide. The trawling only consisted of short, 1km long sections, which took about 10 minutes. Three corridors were trawled per night thus covering about 600,000 sq. metres. The prawn catch on the areas which had not been trawled for over ten years, was about 700 kg. That is about 857 sq. metres bulldozed for every 1 kg of prawns trawled. South Australia has 10 trawlers operating for up to 40 nights a year in the southern area of Gulf St Vincent. These trawlers may have the trawl gear on the bottom for up to 80 minutes and the corridors are up to 8 km long with a total combined trawl width of some 270 metres.Try to do the mathematics on these trawlers operating all night.
One of the few winners in this is the Degens Leatherjacket, even though vast numbers are killed in trawl nets. The Degens Leatherjacket is a sort of "rat of the sea", and, being opportunistic in its feeding habits, actually benefits from the destruction on the bottom and the carrion discarded overboard. Thus its would-be predators become its lunch. This, of course, does not help the balance of nature.
David Suzuki estimates that each year 18 to 40 million tones of bycatch is discarded over the side worldwide. Scraped sea beds take decades to recover after trawling has been stopped. Soft bottom seas, like the sea-bottom here in South Australia, often can never fully recover from the impact. All the world's fisheries are currently in a state of great stress or total collapse with the exception of the water surrounding India. With the population of India compared to that of the rest of the world (especially that of South Australia!) this would seem a little odd. Don't Indians eat seafood? Yes they do, and fishing in India employs hundreds of thousands of people. In South Australia, fishing employs extremely low numbers of people. So why does the Indian marine ecosystem survive where other ecosystems, including ours, do so badly? The answer is simply in the fishing methods used. In India, individual fishermen in communities catch relatively small numbers of whatever is in season and bring it back to the villages to be sorted and sold by the local communities - as they have been doing for hundreds of years. Indians catch less but use almost all of what they catch, and they do not damage the sea-bed in doing so. In Australia, and unfortunately many other places, fishing is calculated purely on value of catch. Fishing licences can be bought or sold, with the owners never even having to set foot on a boat. This means that a prawning licence can be issued on the number of prawn with no reference to bycatch. The prawns are of the higher value, hence fishing continues until thehighest number of the highest-value catch is obtained. To do this, bycatch is discarded. In fact, if the trawlers were to keep their bycatch, they would actually be charged for having undersized fish. I know of one incident of a local trawler operator being charged for keeping some of his own bycatch for personal consumption (his lunch!).
I would challenge anybody to come up with a more environmentally destructive action on the planet than trawling for prawns. I would also challenge anyone to come up with a worse place than the previously biodiverse waters of South Australia. Trawling in South Australia makes a very few people rich, and the rest of us just wonder where our fish went.
Fish seen during 10 dives and on other occasions
When Seen Fish Name Scientific Name Number
Dive Degens Leatherjacket Thamnaconus degeni 1000
Dive Wavy Grubfish Parapercis haackei 50
Dive Jumping Blenny Lepidoblennius marmoratus 50
Dive Silverbelly Parequula melbournensis 4
Dive Yellowback Threefin Helcogramma decurrens 1
Dive Smalltooth Flounder Pseudorhombus jenynsii 1
Caught Goatfish Upenichthys vlamingii 1
Surface South Australian Garfish Hemiramphus melanochir 20
Surface Spotted Pipefish Stigmatophora argus 2
Surface Juvenile Short Boarfish Parazanclistius hutchinsi 1
Total unknown 0
Invertebrates seen during 10 dives and on other occasions
When seen Name Number
Dive Razorfish 10,000
Dive Scallops 100
Dive Starfish 10
Dive Western King Prawn, large 1
Dive Sea Cucumber 1
Dive Sea Pen 1
Dive Large Polychaete worm 1
Caught Western King Prawn, small 2
Caught Red mudcrabs 3
NOTE
Caught: Caught specimens were brought up from the seabed with baited traps.
An Internet picture showing the bycatch
after a trawl for prawns.
Acknowledgement
Trawl Bycatch Australian Marine College Webpage
by Steve Reynolds
Photo Index Officer 1999-2000
The number of slides in our photographic index of South Australian marine life has grown steadily over the past year. At the time of writing, 40 new fish slides have been added, bringing the total number of fish slides to 180.
Another 38 invertebrate slides have been added to the "Index" since last year's report, bringing the total to 84. Four algae slides have also been added to the Index, making the total number of all slides 268.
Slides from the Index are the source of material for our highly successful calendar. David Muirhead continues to be the main contributor of slides towards the Index though it is expected others will contribute during this coming year.
Identification of invertebrate species (and algae) has been a major problem for myself. Members helped to identify several species at our August 1999 meeting. Further unidentified species will have been looked at by the time that this report is published.
Last year's Journal included two full colour pages of slides from our Index. One page featured eleven excellent slides of fish species with their common names. The other page featured twelve just as excellent slides of invertebrates. The common names of most of the invertebrates were given and the scientific names for three species were also given.
I would have liked to have seen a common name used for the Lanceopora obliqua. This pretty bryozoan is known as the Little Fan Bryozoan.
The two nudibranchs featured were identified at our August meeting as Neodoris chrysoderma (the orange nudibranch) and Chromodoris tinctoria (the other nudibranch).
I should point out that the anemones featured were in fact zoanthids (colonial anemones) called Zoanthus robustus. The ascidian featured is actually a colony of colonial ascidians not yet identified by us. The generic name of the sea urchin featured is correct but starts with a capital 'H'. I have called it Holopneustes inflatus in the Index but I note that it was designated as H. pycnotilus in the Journal so I must investigate this discrepancy.
Duckpond are to be thanked once more for their assistance with the duplication of all slides for the Index.
Following are details of the 40 new fish slides and all the 84 invertebrate slides. The four algae slides are as yet still to be identified to any reasonable level.
No.FAMILY GENUS SPECIES COMMON NAME PHOTOGRAPHER
141 Serranidae Othos dentex Harlequin Fish Chris Hall
142 Hypnidae Hypnos monopterygium Numb Fish Chris Hall
143 Enoplosidae Enoplosus armatus Old Wife Chris Hall
144 Monacanthidae Scobinichthys granulatus Leatherjacket, Rough David Muirhead
145 Monacanthidae Eubalichthys gunnii Leatherjacket, Gunn's David Muirhead
146 Pentacerotidae Parazanclistius hutchinsi Boarfish, Short David Muirhead
147 Syngnathidae Phycodurus eques Seadragon, Leafy David Muirhead
148 Cheilodactylidae Cheilodactylus spectabilus Morwong, Banded David Muirhead
149 Ophidiidae Genypterus tigerinus Ling, Rock David Muirhead
150 Labridae Dotalabrus aurantiacus Wrasse, Castlenau's (m) David Muirhead
151 Antennariidae Rhycherus filamentosus Angler, Tasselled Paul Fitzgerald
152 Urolophidae Urolophus Sp. Stingaree David Muirhead
153 Monacanthidae Acanthaluteres spilomelanurus Leatherjacket, Bridled David Muirhead
154 Pomacentridae Parma victoriae Scaly Fin, Victorian David Muirhead
155 Odacidae Siphonognathus beddomei Weed Whiting, Pencil (f) David Muirhead
156 Odacidae Siphonognathus caninus Weed Whiting, Sharp-nosed David Muirhead
157 Callionymidae Foetorepus calauropomus Stinkfish, Common David Muirhead
158 Odacidae Odax acroptilus Cale, Rainbow (m) David Muirhead
159 Odacidae Neoodax balteatus Rock Whiting, Little (f) David Muirhead
160 Odacidae Neoodax balteatus Rock Whiting, Little (m) David Muirhead
161 Monacanthidae Scobinichthys granulatus Leatherjacket, Rough David Muirhead
162 Cheilodactyidae Cheilodactylus nigripes Morwong, Magpie Perch David Muirhead
163 Monacanthidae Eubalichthys cyanoura Leatherjacket, Blue-tailed (f) David Muirhead
164 Gobiidae Nesogobius Sp. Goby, Opalescent David Muirhead
165 Pempheridae Pempheris klunzingeri Bullseye, Rough David Muirhead
166 Labridae Dotalabrus aurantiacus Wrasse, Castlenau's (f) David Muirhead
167 Odacidae Odax acroptilus Cale, Rainbow (m) David Muirhead
168 Plesiopidae Trachinops noarlungae Trachinops (Hula fish) David Muirhead
169 Labridae Pictilabrus laticlavius Senator Fish (m) David Muirhead
170 Diodontidae Diodon nichthemerus Globe Fish David Muirhead
171 Syngnathidae Phycodurus eques Seadragon, Leafy David Muirhead
172 Syngnathidae Phycodurus eques Seadragon, Leafy David Muirhead
173 Carangidae Trachurus novaezelandiae Scad, Yellow-tail David Muirhead
174 Tripterygiidae Helcogramma decurrens Threefin, Yellow-backed (m) David Muirhead
175 Antenneriidae Rhycherus filamentosus Angler, Tasselled Paul Fitzgerald
176 Monacanthidae Eubalichthys cyanoura Leatherjacket, Blue-tailed (f) David Muirhead
177 Odacidae Siphonognathus caninus Weed Whiting, Sharp-nosed (f) David Muirhead
178 Mugiloididae Parapercis haackei Grubfish, Wavy David Muirhead
179 Gobiidae Callogobius depressus Goby, Sculptured David Muirhead
180 Scorpaenidae Maxillicosta scabriceps Scorpionfish, Little David Muirhead
No. PHYLUM CLASS GENUS SPECIES COMMON NAME
2001 Mollusca Gastropoda Chromodoris tinctoria Nudibranch
2002 Mollusca Cephalopoda Squid
2003 Mollusca Gastropoda Aphelodoris lawsae? Nudibranch
2004 Mollusca Cephalopoda Cuttlefish
2005 Mollusca Cephalopoda Cuttlefish
2006 Mollusca Gastropoda Neodoris chrysoderma Yellow Nudibranch
2007 Mollusca Bivalvia Scallop
2008 Mollusca Cephalopda Cuttlefish
2009 Mollusca Cephalopoda Cuttlefish
2010 Mollusca Gastropoda Shell egg mass
2011 Mollusca Gastropoda Nudibranch
2012 Mollusca Gastropoda Chromodoris tinctoria Nudibranch
2013 Mollusca Gastropoda Yellow Dorid
2101 Cnidaria Anthozoa Zoanthus robustus? Zoanthids
2102 Cnidaria Anthozoa Sarcoptilus sp. Orange Sea Pen
2103 Cnidaria Anthozoa Sarcoptilus grandis? Sea Pen
2104 Cnidaria Anthozoa Zoanthus robustus Zoanthids
2105 Cnidaria Anthozoa Phylctenactis tuberculosa Swimming Anemone
2106 Cnidaria Anthozoa Coral, Stony
2107 Cnidaria Hydrozoa Hydroids
2108 Cnidaria Anthozoa Pseudogorgia Sp. Pseudogorgian
2109 Cnidaria Hydrozoa Halocordyle disticha? Hydroids
2201 Chordata Ascidiacea Clavellina moluccencis Ascidians, Diminutive
2203 Chordata Ascidiacea Colonial Ascidians
2204 Chordata Ascidiacea Colonial Ascidians?
2205 Chordata Ascidiacea White Solitary Ascidians
2206 Chordata Ascidiacea Yellow Solitary Ascidian
2207 Chordata Ascidiacea Polycitor giganteus Colonial Ascidian
2208 Chordata Ascidiacea Aplidium multiplicatum Compound Ascidian
2209 Chordata Ascidiacea Clavellina moluccencis Ascidians, Diminutive
2210 Chordata Ascidiacea Polycarpa clavata Sea Tulip
2211 Chordata Ascidiacea Compound Ascidians
2212 Chordata Ascidiacea Clavellina moluccencis Ascidians, Diminutive
2301 Echinodermata Asteroidea Nectria macrobrachia Large-plated Seastar
2302 Echinodermata Asteroidea Nectria wilsoni Seastar
2303 Echinodermata Ophiuroidea Conocladus australis Basket Star
2304 Echinodermata Asteroidea Pentagonaster duebeni Vermillion Star
2305 Echinodermata Echinoidea Holopneustes inflatus Sea Urchin
2306 Echinodermata Echinoidea Goniocidaris tubaria Sea Urchin
2307 Echinodermata Asteroidea Plectaster decanus Mosaic Seastar
2308 Echinodermata Asteroidea Nepanthia troughtoni Sea Star
2309 Echinodermata Asteroidea Petricia vernicina Velvet Seastar
2310 Echinodermata Asteroidea Plectaster decanus Mosaic Seastar
2311 Echinodermata Asteroidea Austrofromia polypora Many-pored Seastar
2312 Echinodermata Ophiuroidea Astroboa ernae Basket Star
2313 Echinodermata Asteroidea Luidia australiae Southern Sand Star
2314 Echinodermata Asteroidea Nectria ocellata Ocellate Sea Star
2315 Echinodermata Asteroidea Coscinasterias calamaria 11-armed Sea Star
2316 Echinodermata Asteroidea Austrofromia polypora Many-pored Sea Star
2317 Echinodermata Asteroidea Allostichaster polyplax Many-armed Sea Star
2318 Echinodermata Asteroidea Petricia vernicina Velvet Sea Star
2319 Echinodermata Asteroidea Tosia australis Biscuit Star
2320 Echinodermata Ophiuroidea Ophiarachnella ramsayi Ramsay's Brittle Star
2321 Echinodermata Asteroidea Luidia australiae Southern Sand Star
2322 Echinodermata Asteroidea Petricia vernicina Velvet Sea Star
2323 Echinodermata Asteroidea Anthaster valvulatus Sea Star
2401 Arthropoda Crustacea Sponge Crab
2402 Arthropoda Crustacea Crab
2403 Arthropoda Crustacea Portunus pelagicus Blue Swimmer Crab
2404 Arthropoda Crustacea Spider Crab
2405 Arthropoda Crustacea Crab w/- ascidians
2406 Arthropoda Crustacea Jasus edwardsii Southern Rock Lobster
2407 Arthropoda Crustacea Jasus edwardsii Southern Rock Lobster
2501 Porifera Finger Sponge
2502 Porifera Organ Pipe Sponge
2503 Porifera Demospongiae Aplysilla rosea Pink Aplysilla
2504 Porifera Sponge
2505 Porifera Finger Sponge
2506 Porifera Sponges (2)
2507 Porifera Organ Pipe Sponge
2508 Porifera Calcarea Sycon Sp. Calcareous Sponge
2509 Porifera Sponge
2510 Porifera Sponge
2511 Porifera Demospongiae Cliona Sp. Sponge
2512 Porifera Demospongiae Ciocalypta Sp. Demospongiae
2513 Porifera Cup Sponge
2514 Porifera Sponge
2515 Porifera Sponge
2601 Bryozoa Gymnolaemata Membranipora Sp. Bryozoan
2602 Bryozoa Gymnolaemata Lanceopora obliqua Little Fan bryozoan
2603 Bryozoa Gymnolaemata? Celleporaria Sp.? Bryozoan
2604 Bryozoa Bryozoan
2605 Bryozoa Gymnolaemata? Celleporaria Sp.? Bryozoan
2701 Annelida Fan worm
All of the Invertebrate photographs were taken by David Muirhead.
Marine Fossils In The Flinders Ranges
by Steve Reynolds
South Australia's Flinders Ranges contain a great number of fossils of marine species. These include jellyfish, segmented worms, sea pens, stromatolites, tiny molluscs and coral-like creatures.
Details of these fossils are given in "Corridors Through Time", a pamphlet about the geology of the Flinders Ranges National Park published by the Department of Mines and Energy.
The pamphlet explains how the Flinders Ranges were formed. It says that "Rocks which today form the Flinders Ranges were once sediments deposited in a shallow sea. This happened between 1100 and 500 million years ago when a trough called the Adelaide Geosyncline extended across South Australia. A thickness of up to 24 km of sediments was laid down in this trough as it sank slowly into the earth's crust. These bear a record of ancient life forms stretching over hundreds of millions of years.
At the end of the Cambrian Period (See Chart 1 on Page 12 {Editor's note}) - around 500 million years ago - the rocks were buckled and pushed up into a mountain chain much higher than the one we see today. Subsequent erosion by wind and water has worn the mountains down to their roots leaving behind what we now call the Flinders Ranges - one of the world's great geological monuments."
The pamphlet goes on to describe areas such as Wilpena Pound and Brachina Gorge and the fossil record in the Flinders Ranges. It says that "Evidence of the history of life during one of its most important periods of evolution can . . be seen."
Stromatolites are described as being one of the earliest life forms on earth. They are dome-shaped, colonial reef-like structures which have been produced by photosynthesizing blue-green bacteria. They are living a precarious existence and are nearly extinct. Stromatolite fossils can be seen as faint outlines and ridges in Precambrian limestone rocks in the Trezona Range in Brachina Gorge.
About 600 million years ago jellyfish, segmented worms and sea pens lived in the sediment on the bottom of a shallow tidal lagoon. The sediment eventually solidified into rock and embedded the creatures.
Jellyfish and sea pens are both cnidarians (phylum Cnidaria) whilst segmented worms belong to the phylum Annelida. Jellyfish belong to the class Scyphozoa whilst sea pens are part of the class Anthozoa. They are octocorals (subclass Octocorallia) and therefore related to alcyonarians (soft corals & sea fans).
Some of these creatures have been preserved as rock impressions west of Beltana. They are known as Ediacara Fauna because they occur in the Ediacara Hills within particular layers of quartzite which forms the steep sides of Brachina Gorge. Ediacara is Aboriginal for "granite plain". Beltana is Aboriginal for "running water".
Quartzite is an extremely hard, resistant rock. It is formed from sandstone by the filling of the pore spaces with quartz. Quartz is the commonest mineral. Pure quartz is glassy in appearance and is brittle but it is so hard that it will scratch glass. It consists of silica and forms the major proportion of most sands. It is also present in many rocks and soils in a wide variety of forms. It often fills veins, joints and cavities and often contains admixtures of other minerals including ores.
Trilobites, tiny molluscs and some unique coral-like creatures lived in large numbers attached to the sea bottom in clear water.
Trilobites, were marine arthropods (class Arthropoda) and they superficially resembled woodlice. They were bottom-dwellers ranging in size from 6mm to 750mm . They shed their exoskeletons as they outgrew them. They have now been extinct for over 200 million years.
Molluscs are soft-bodied creatures with a hard shell. The coral-like creatures are known as Archaeocyatha which means "ancient cup". They are commonly referred to as Archaeo and they are the most numerous, obvious and spectacular fossils there. They are said to be related to sponges and are found in bands of limestone near the western end of Brachina Gorge.
According to Hans Mincham in his book "The Story of the Flinders Ranges" the Archaeo "produced a beautiful framework which took the form of an outer cup united to an inner one with a fine radial rafterwork, the walls of both being shot through with holes that, it seems, allowed sea-water to circulate through them. Of the many species, most, resembling an icecream cone in shape, grew up from the sea-floor on slender stems."
Fossils of some of these creatures are found in Cambrian rocks, rocks from the Cambrian period some 500 million years ago. The creatures are referred to as Cambrian Fauna. Archaeocyatha, mollusc shell fragments and algal structures are found in Cambrian rocks in the western tributaries of Brachina Gorge.
Archaeocyatha fossils occur in Ajax Mine near Beltana. They are also found in Wilkawillina Gorge. The boundary between Precambrian rocks and those of the Cambrian Period occurs in this gorge. Archaeocyatha can be seen in the gorge walls where Mount Billy Creek follows the trace of a small fold in Cambrian rocks.
References
"Marine Fossils in Flinders Ranges" by Steve Reynolds, MLSSA Newsletter May 1996 (No.222).
"Stromatolites" by Steve Reynolds, MLSSA Journal No.10, December 1999.
"Corridors Through Time", a pamphlet about the geology of the Flinders Ranges National Park, Department of Mines and Energy.
"The Story of the Flinders Ranges'' by Hans Mincham.
"Marine Invertebrates of Southern Australia - Part I", Shepherd & Thomas, Government Printer, 1982.
"Corals of the Great Barrier Reef", S.Domm, Ure Smith, 1976.
"Touring the Flinders Ranges", RAA of SA, 1987.
Eco-Logical Alter-Natives for Adelaide Coastal Plantings
by David Muirhead
There are three things you can be sure of: taxes, infidelity and the rise of the natives.
Choice of coastal plants in gardens and public places along our metropolitan foreshore has expanded considerably in recent years.
In my youth most were introduced species whereas now probably more than half are Australian natives, including an increasing representation of local natives.
While I'm naturally pleased with this trend I remain amazed and frustrated by the virtual absence of many excellent smaller local natives in such plantings in these supposedly enlightened times. For 200 years, Australians have worked ceaselessly to modify their environment, all the while falling ever more in love with wild Australia.
The inevitable breaking of ties with the homelands, notably Great Britain, has been paralleled by a change in approach to gardening with a greater acceptance of our indigenous plants.
The fact that WA alone contains more species of flowering plants than Europe and North America combined has made this initially hesitant assimilation all the more easy.
But where do we go from here? While horticulturalists produce ever more cultivars to tempt the small suburban gardener, and enthusiasts expound the virtues of the bush garden, is there another trend? I see that there is. That trend is towards gardens that contribute more to, and take less from, the environmental health of the planet. Yes, responsibility is invading the garden world. At present larger quantities of fertilizer, insecticide and herbicide are applied to our urban landscapes than ever before in our history.
Even as we lament the vast monocultures of our farmlands, and favour organically grown foods, we Aussies are bucketing our rivers and oceans with obscene loads of nutrients and toxins in pursuit of our right to garden. But all rights have matching responsibilities. Australian gardeners now increasingly realise this. The proliferation of mulching practices, worm farms and books on Wirras proves my point.
It is likely that within a decade, even slow release fertilizers will be uncommon on our shelves, cats will be confined to pens and gardens with a true local native flavour will take off as the 'in' thing. At the same time, penalties for breaching quarantine regulations on foreign plants will increase dramatically and gardens in outer suburban areas will have restrictions on which species they can safely plant without grave risk of bushland invasion.
Although nurseries will always claim to be responding to demand, I'm sure a more entrepreneurial approach would pay dividends. To paraphrase Wal Bushman in "Wirra the Bush that was Adelaide", Nature Conservation Society, 1986 "One of the regrettable trends of present times is the homogenisation of the suburban garden. When landscapers have finished with any locality it soon resembles every other locality, containing the same favourite landscaping plants that may be seen right across the continent. In nature, things are different. Every locality has its own particular environment. A Wirra is a celebration of the individuality of a place. Wirra brings back the natural character of a place and it is the only planting that does this.
Wirra is thus ahead of its time. Early next century, Wirra will be the rage."
So, dear reader, let's get started! Next time you're about to plant, forget your local nursery's New Zealand Christmas Bushes, Wandering Jew and exotic palms (palms in Adelaide? - I mean really!!) and phone up one of the small but increasing number of nurseries specialising in local natives such as Themeda and you'll have opened the door to a fascinating world that once existed at your doorstep. And, believe it or not, some recognised weeds are still being sold in our local nurseries (eg English Broom, Blue Periwinkle, Watsonia and some ornamental grasses) and it is only a matter of time before other nursery species (eg lavender, various daisies, gazanias) become garden escapes and so join the hundreds of feral plant species choking this great land.
I will not attempt an exhaustive listing of suitable local natives for local coastal gardens but rather present a few favourites in each main group, based on size or habit. Readers are referred to "Pre-European Vegetation of Adelaide: A survey from the Gawler River to Hallett Cove" by Darrell N. Kraehenbuehl 1996 (published by The Nature Conservation Society of SA Inc.) for a very comprehensive list of suitable species.
TREES
Eucalyptus microcarpa Grey Box
Eucalyptus porosa SA Mallee Box
Melaleuca lanceolata Dry Land Tea Tree
Allocasuarina verticillata Drooping Sheoak
Callitris preissii Native Pine
Acacia salicina Broughton Willow Wattle
Acacia retinodes Wirilda
SMALL
TREES/LARGESHRUBSMelaleuca halmaturorum Kangaroo Honey-myrtle
Myoporum insulare Coast Blue-Berry (Boobialla)
Banksia marginata Silver Banksia (Honeysuckle)
Pittosporum phyllaerioides var. phyllaerioides Weeping Pittosporum (Native Apricot)
Santalum acuminatum Quondong
Acacia pycnantha Golden Wattle
SHRUBS
Dodonaea viscosa subsp. spatulata Sticky Hopbush
Bursaria spinosa Christmas Bush/Sweet Bursaria
Leptospermum myrsinoides Heath Tea Tree
Grevillea ilicifolia var. ilicifolia Holly-leaved Grevilliea
Rhagodia candolleana sub sp. candolleana Sea-berry Saltbush
Rhagodia parabolica Fragrant Saltbush (Mealy Saltbush)
Lavatera plebia Native Hollyhock
Atriplex cinerea Silver Saltbush (Grey Saltbush)
Maireana brevifolia Small-leaved Blue-bush
Scaevola angustata Coast Fan-flower
Acacia acinacea Gold-dust Wattle
Acacia ligulata Umbrella Bush
Acacia nematophylla Wallowa
Acacia victoriae Elegant Wattle
Acacia paradoxa Kangaroo Thorn
Lasiopetalum baueri Slender Velvet-bush
GROUND COVERS/ROCKERY PLANTS
Enchylaena tomentosa Ruby Saltbush
Myoporum parvifolium Creeping Boobialla
Lotus australis Native Lotus
Kennedia prostrata Scarlet Runner
Swainsona lessertifolia Coast Swainson-pea
Bracteata bracteatum Golden Everlasting
GRASSES/SEDGES/LILLIES
Isolepis nodosa Knobby Clubrush
Themeda triandra Kangaroo Grass
Lepidospermum gladiatum Sword Sedge
Dianella revoluta Blue Flax-lilly
Bulbine bulbosa Bulbine Lilly
CLIMBERS/CREEPERS
Muehlenbeckia gunni Coast Sarsparilla
Clematis microphylla Old Man's Beard
Hardenbergia violacea Native Lilac
Tetragonia implexicoma Coast Spinach
Einadia nutans Climbing Saltbush
And, in the end, the plant you plant, is equal to the species you save.
Or
Does that mean I've been going around in circles?
By Voronica Whitney-Robinson
Exotics Biotechnician
The Seattle Aquarium
Seattle, WA USA
Late July of 1997 was an interesting summer. My supervisor was taking a leave from work at The Seattle Aquarium (TSA) and enjoying some time with his new daughter. And I was enjoying some time away from him. It made me feel as though I had a little more responsibility and a touch more freedom without him around. In fact, as he left, my supervisor gave me a project that ended up consuming a fair bit of time, and fueling my passion for a very special fish.
His assignment to me was to come up with a new list of critters for one of the areas for which we were responsible. Between my supervisor, another co-worker, and myself we are the team who are accountable for caring for all the exotic or non-local animals at the Aquarium. The first display area, where I do most of my work, is known as Adaptations. There are 19 display tanks alternating between freshwater and saltwater animals. Near every few tanks are graphic panels that discuss some aspect of how fish have adapted to life in water. The idea is that the tanks near those topics are examples of the pertinent topic. My supervisor felt that the time had to come to work up a new list of replacement animals that were still good examples of the various subjects, but different species of fish from what was already there. So, I made up a list of all the topics covered in Adaptations, plopped myself down in our library and began to paw through all the various tomes we had on exotic fish.
Not long into my search, I opened up one of Burgess's books on marine animals. Not a book that always has all the information I would like but it does have some great photos and a lot of basic info specific to the fish. One of the panels I needed a new critter for was "Reproduction". We had Hippocampus kuda, the yellow seahorse, as our current example animal with a neat feature. The fact that a male anything can carry babies always surprises the public, and these fish were a big hit, with their kangaroo-like pouches. So I started paging through the selections of syngnathidae first for my replacements. I didn't feel too confident to look at a different family for a substitute. I hadn't gotten very far when I saw an amazing photo: Phycodurus eques otherwise known as a Leafy Seadragon. Even Mr. Burgess seemed to recognize the unusualness of this particular syngnathid because he devoted several photo spaces to both the Leafy and Weedy (Phyllopteryx taeniolatus) Seadragon. While the clownishly colored Weedy was a sight, I'm afraid I fell hard for its more ornate cousin. There's no need to elaborate on the ephemeral beauty of the animal, as anyone who has seen one knows they almost defy description. I fell under the Leafy's spell.
As I recall, when I e-mailed my choices for replacements to my supervisor, I underlined the Leafy and followed the scientific name with all sorts of begging and pleading. I really wanted this particular fish. While I waited breathlessly for his response, I started to search for as much husbandry data as I could. Like most everyone, I was falling into the trap of searching "the web" for information, because it was so quick and easy. "Leafy Seadragon", or even "Weedy Seadragon", brought a lot of search engines to a grinding halt. There were tantalizingly few useful sites buried in a sea of hits about leafy greens and other cocktail trivia. The lack of much relevant information made me even more curious at that point.
When my supervisor did get back to me, he explained that TSA had tried to get the animals before, but they were very rare, very difficult to keep, and very expensive. As the Seattle Aquarium is a division of the City of Seattle, budgets are always tight and money is hard to come by. The Director of the Aquarium has a lot of issues to weigh when a staff member comes up with an exhibit idea, and the exhibit idea doesn't always come in as the highest priority. Leaky roofs and broken windows are some of the many unforeseen items that can occur in a year and suck a limited budget dry. It appeared as though I was at an impasse. But having seen the critter, I just had to learn more. And so began a long journey for me on the Internet.
Having been initially stymied by the apparent lack of information on Leafies, I began to search various aquarium sites to see who had them. And once I found someone who did care for them, I bombarded him or her with every question imaginable. In the winter of 1997, I began a long running conversation, via e-mail, with Paul Groves, the head aquarist at Perth's Underwater world. He was immediately very helpful and patient with all of my myriad questions and general ignorance. Once I found him, the door opened for me on a small world of people knowledgeable on the subject of Seadragon husbandry.
I think one of the facets about the animal that excited me so much was the fact that there was and is so much that remains a mystery about them. There is the element of discovery and new frontiers that surrounds them and the idea of bringing that mystery and excitement to the general public is very intoxicating. The more I learned, the more I felt that the general public I serve should know and see them as well. How could someone not look at Seadragons and tilt their heads in amazement and awe at the wonders our oceans offer up?
Like a dog worrying a bone, I would bring up the subject of the animal with my supervisor, other staff, and the management that has to say "no" to most everything, and "yes" to so few things. The critters were worth fighting for, even though the disappointments were difficult to steer through at times.
In early August of 1998, while surfing on the internet for my favorite subject, I discovered an interesting news item. A brief website description mentioned an organization with the initials MLSSA and a man named Tony Isaacson, who had taken video footage of Leafy Seadragons being born! I jumped at the opportunity and sent my standard "this is who I am" and "this is what I'm trying to learn about" off to Philip Hall, President of the Marine Life Society of South Australia and crossed my fingers.
Within a few days, I received a very cordial and invaluable response from Philip with a few important contact people involved with various aspects of Seadragon husbandry and conservation, Tony Isaacson's e-mail address, and MLSSA's very justified views on Seadragon conservation. I was off and running.
It only took a few days for Tony to respond to my query. He was cheerful and directed me to another American, William B. Henry, who already had a copy of his tape and had converted it into the format needed for viewing in North America. This gentleman, it seemed, was a sculptor and wanted some good images of Leafies to work with. He had come up against the same difficulties I had in obtaining a variety of images of Leafies. But Tony's e-mail didn't end there. He also included a list of contacts and very tactfully cautioned me in how I approached this limited community. More often than not, over the next year, Tony would offer advice and sympathy with my frustrations. He also had his own struggles and understood my desire to bring these animals into the public eye in a manner that also kept conservation in sight. He is also fighting to bring about an exhibit in SA so the people of Southern Australia can easily view these unusual fish that are endemic to their own province.
By the time 1999 rolled around, it looked as though some kind of syngnathid display might be a possibility at TSA. I was soaring at the thought. But also dismayed at several new hurdles that had developed.
As anyone who provides care for Leafies knows, the bulk of their diet consists of mysid shrimp. While we have a local mysid in Puget Sound waters, they are seasonal and something we could not rely on as a steady source of food for the Leafies. Most of the US aquariums exhibiting Leafy or Weedy Seadragons purchase their mysids from the same source in Florida: Aquatic Indicators. This small company has an excellent reputation and has, to date, never missed a shipment to any of its clients. While that would have been the obvious choice, the Washington State Department of Fish and Wildlife had made regulatory changes that made importing Florida mysids nearly impossible. In 1998, the insidious green crab made its way into Washington State waters potentially threatening the livelihood of our local shellfish farmers. A continuous influx of an out-of-state, wild-caught shrimp from Florida was basically impossible. Another method for feeding the Leafies had to be found.
As if this were not enough, the second major hurdle I faced was the fact that an exhibit committee had been formed. Now I had to convince the committee to spend the money required to obtain, house and feed Leafies. I was daunted, but did not feel defeated yet.
The way around the issue of food took a little time. A lab in Colorado cultured mysids for toxicology studies and the Department of Fish and Wildlife deemed their facility and conditions acceptable for import. Because of the much higher cost per shrimp, however, they would have to be cultured on site to make the food budget acceptable. A permit application was submitted to the State and a rearing area was set up at the Aquarium.
The committee was a different matter. The group, as a whole, thought that perhaps some kind of seahorse display, on the lines of what the Shedd Aquarium had opened the previous year, would be a good idea. The biggest stumbling block was still the cost of the Seadragons. The director was troubled by the $2,000US cost per animal plus shipping. But, she agreed that if a sponsor could be found to cover the costs of the Leafies, she would accept the committee's recommendations, otherwise, a seahorse display would be done without Leafies. In March of 1999, I began to write a proposal for my only ace in the hole: a company called Wizards of the Coast.
The previous Autumn, I had done some freelance writing for this company and saved them from a jam of sorts. I had one marker I could call in. And, as the company that owned the role playing game, Dungeons & Dragons, I couldn't think of a more obvious sponsor for our own dragons. I made an appointment to talk to one of their marketing people and I was off again.
The two representatives at Wizards of the Coast appeared somewhat interested. I pulled out my Australian Geographic and Scientific American, which had some excellent photographs of adult and juvenile Leafies. I haven't met anyone who hasn't had to take a second look at Seadragons. These two were no exception. It turned out one of the representatives husbands had gone to school with and had dove with TSA's divemaster. I felt fairly confident they would agree to the sponsorship.
By May, Wizards of the Coast had committed to cover the costs of the breeding loan agreement between the Dallas World Aquarium and TSA. The breeding loan seemed the best way to minimally impact the numbers of Leafy Seadragons worldwide. Dallas had a sizable number of captive reared offspring on hand, and was willing to loan them out on a renewable basis. In this way, we would be able to display animals that were not wild-caught. And the animals would have a lower stress level coming in from Dallas, rather than being shipped all the way from Southern Australia.
It is now November 1999, and, as always, a few changes have occurred. An interim director is running the Aquarium while our Director is on leave. Our State import/holding permit still need amendments for us to efficiently rear mysids within our facility. The exhibit itself is being expanded. But one thing still appears certain, Leafy Seadragons will be on exhibit at TSA in the year 2000. Looking back at the past months, I'm counting on the Year of the Dragon to be an interesting one!
Male Leafy Seadragon, with eggs.
Acknowledgements
Leafy Seadragon David Muirhead