Marine Life Society of South Australia
Inc.
Newsletter
July 2007 No. 345
“understanding, enjoying & caring for
our oceans”
Next Meeting
Wednesday 18th July
This will be the July General Meeting and it
will be held as usual at the Conservation Centre, 120 Wakefield Street,
Adelaide and it will commence at 8.00pm.
We will have a members night so if you have video’s, slides or
other presentations then please contact Robert Browne to organise the
programme.
His email details
are:
robert.browne@gmail.com
CONTENTS
Imported Aquarium Fish
Threaten Aquatic Biodiversity (Robert Browne and Neville Skinner)
Umbrella Shells (Steve Reynolds)
2008 Calendars
The 2008 edition of our widely acclaimed
calendar is ready for sale. This makes the 10th calendar we have produced
and thanks must go to Phill McPeake who has done the majority of the
painstaking work in creating another masterpiece. Assistance from Danny Gibbins
Philip Hall, David Muirhead and Geoff Prince has also been invaluable.
We ask that members take as many as
possible to sell. Member price is again $6 with general sales set at $10 copy.
Imported
Aquarium Fish Threaten Aquatic Biodiversity
by Robert
Browne, MLSSA Scientific Officer
with additions
by Neville Skinner
The import of
Aquarium Fish to Australia threatens the endemic aquatic biodiversity of both
freshwater band marine eco-systems, and could devastate Australia’s aquaculture
industry. This trade is mostly unnecessary and can threaten Australian species
through the introduction of disease, escapees establishing feral populations,
and discouraging the establishment of Australian endemics as aquarium
species.
The risks
associated with both pathogens and feral species demands the highest quarantine
standards and a very high justification of the importation of any aquatic
species. These requirements are not mandate in Australia’s quarantine
practices. The legislation and implementation of these requirements should be a
high priority for any aquatic conservation organization. To fail will inevitably
mean the devastation of whole groups of Australia’s aquatic species.
Each year
8-10million ornamental aquarium fish are imported into Australia from about 100
countries. The hazards of the import of
these fish are little known with few scientific publications on ornamental fish
disease, compared to farmed fish disease, and much fewer when compared to
disease in terrestrial species. In 2006, 22 species of feral ornamental fish
were established in Australian waterways with numerous freshwater plants and
mollusks. These aquatic organisms can provide direct transmission for
establishing pathogens in native fish and other aquatic life (ABC 2007).
Australia has a stringent
policy relative to other countries which includes pre-border health
certification and a mandatory quarantine period at border of 1-3 weeks in
registered government supervised quarantine premises. Nevertheless many
diseases have been established from ornamental fish in farmed native Australian
and free living introduced fish. These include viral, bacterial, fungal,
protozoal and metazoan pathogens with recent escapees including Aeromonas
salmonicida. Aeromonas salmonicida has the capacity to devastate the
salmon and trout industry and unknown species of native fish (Whittington and
Chong 2007).
Australia’s
stringent quarantine policies for imported ornamental fish have been shown to
be inadequate for the prevention disease incursions and exotic pathogens will
become established as a result of the ornamental fish trade. Prof Whittington
said (sic), “The number of ornamental fish traded and permitted sources need
dramatic reduction to facilitate hazard identification, risk assessment and
import quarantine controls”. Although a
quarantine period of three weeks is mandatory for imported fish, many
introduced diseases have passed quarantine (ABC 2007). Quarantine requirements
to prevent the establishment of any possible disease should be mandatory,
irrelevant of the quarantine period required.
Neville Skinner,
MLSSA secretary says “I understand Prof Whittington was talking about the
potential diseases carried in on these exotic imports; but I would like to
extend the point to why we allow these species in the first place!
Perhaps a good starting point for fish quarantine would be a valid justification
in terms of public benefit to import a species.”
Quarantine
requirements should also include strict provisions to justify the import of any
aquatic species to lower the risk of feral species. Imported species continue to offer a threat
to aquatic biodiversity. A good example being the European carp now widely
spread in Australian freshwaters. Besides disease prevention the restriction of
the import of fish would also encourage the keeping of native fish and the
establishment of attractive varieties to establish captive populations in
case of crashes in wild stocks (Ziemann 2001). The creation of a dynamic
and substantial aquarium and aquaculture industry with native Australian fish
is essential to the maintenance of their biodiversity. Current aquarium species
can be produced in Australia, with the need for novel types being generated
from native species.
There have been
a number of instances of close calls and failures to prevent the spread of
disease from imported fish. Professor Richard Whittington says “...the gourami
iridovirus killed 90 per cent of Murray cod on a farm in Victoria and could
have been devastating if it infected wild Murray cod, which is considered a
threatened species. Fortunately the farm
did not discharge its effluent into a river, a common industry practice” (ABC
2007).
Another example
of the ease with which fish escapees or associated disease could affect
precious freshwater systems. Skinner says “And then consider this point in the light
that a trout farm adjacent to Ewens Ponds discharges its water into Ewens Pond
3, which contains 6 to 7 species of protected &/or endangered native fish.
What if either the trout or their diseases escaped into the Ewens Ponds/Eight
mile Creek system.” Even if imports are allowed why can’t they be managed to
prevent reproduction. There are a number of ways to prevent the reproduction of
fish, including chemicals, sterile hybrids, or the legal importation of fish of
only one sex.
Disease through
imported fish also threatens Australia diverse range of unique and freshwater
crustaceans. These include the well known aquaculture and recreation species
yabbies, redclaw and marron. However, Australia is also home to the largest
freshwater crustacean the encouraged Tasmanian giant crayfish (Wikipedia 2007:
IUNC 2007), and a range of large beautiful species of aquarium potential found
along the eastern coast of Australia (NFA 2007). There are also many
terrestrial crayfish of great biological significance.
In Europe, the
crayfish plague fungus Aphanomyces astaci has eliminated many native
European stocks of crayfish. The crayfish plague is believed to have originated
in the 1860’s in Lombardy, Italy from introduced North American freshwater
crayfish and then the disease spread through Europe. Crayfish plague entered
Britain in 1981 and also now infests Turkey, Greece and Norway. What is to stop
similar diseases entering Australia through imported water or fish. The 21 day
quarantine period would not necessarily expose such pathogens.
Environmental
tragedy on a global scale has occurred to amphibians through the release by
inadequate quarantine practices of aquatic Chytrid fungus. This disease is
responsible for many frog extinctions in Australia, and is currently wiping
frogs out on mass in South America. Nearly one-third of the world's 5,743
amphibian species are classified as threatened with extinction and the
amphibian fungal disease chytridiomycosis is the worst infectious disease ever
recorded among vertebrates in terms of number of species impacted and threat of
extinction (Browne et al. 2007: CI 2006).
Problems with
the importation of unsanitised aquatic products have already extended to the
marine environment. These include both the possibility of aquarium supplies and
unknown sources. Caulerpa taxifolia
was probably introduced into South Australia, and other countries, from
aquariums. This invasive marine weed has the potential to reduce fisheries
production and reduce marine biodiversity (NOAH 2007). In southern Australia
the mass die offs of pilchards followed a pathology pattern consistent with a
novel exotic pathogen. However, no direct evidence was obtained to determine
the possible method for any introduction (Fletcher et al. 2007).
Skinner says another
example of poor quarantine in general is the importation of unfumigated wooden
pallets. Australian manufacturers exporting to Europe are compelled to use
clearly marked ‘Fumigated Pallets’ in accordance with the “ISPM15”
international standard, but the same companies when importing goods on wooden
pallets are not required to specify ‘Fumigated Pallets’ indicating a general
malaise in quarantine laws in Australia.
Even though the
quarantine regulations need improvement the Australian Quarantine and Inspection
service is vigorously pursuing offenders. In 2007 offenders imported aquarium
fish in Perth, a 45 year old female was fined more than $30,000 for attempting
to smuggle 51 exotic aquarium fish through Melbourne airport, and as a
consequence of a two year investigation a Brisbane aquarium fish importer was
sentenced to two and a half years prison for attempted fish smuggling. A 2.5
kilogram red piranha that may have been imported legally in the past as a
fingerling was seized in Adelaide (AQIS 20/04/07).
All four cases
illustrate the importance of Australia’s quarantine laws. Prohibited fish could
introduce exotic viruses, fungi or parasites that could threaten Australia’s
native fish and amphibians and aquaculture industries. Escaped aquarium fish could
also prey on native species, compete for food or destroy river and lake
habitats (AQIS-20/04/07).
References:
ABC Science
Online. 2007. Aquarium fish ‘threaten biodiversity’, Anna Salleh,
http://www.abc.net.au/news/newsitems/200705/s1927246.htm
AQIS Press release 20/04/07 AQIS 20710. Media contact Carson Creagh: 02 8334 7645,
0414 577 427.
Browne, R.K., Zippel, K., Odum A.R., Herman, T.
2007. Physical facilities and associated services. Use of amphibians in
research, laboratory, or classroom settings.
Institute for Laboratory Animal Research (ILAR), Volume 48, 3 (in
press).
CI. 2006. Conservation International. Science:
Global Action Team Needed to Stem Amphibian Extinction Crisis.
http://www.conservation.org/xp/news/press_releases/2006/070606.xml
NFA. 2007. Native Fish Australia. Spiny Freshwater
Caryfish. http://www.nativefish.asn.au/spiny.html
NOAA. 2007. Facts about Caulerpa taxifolia. NOAA. National Marine Fisheries Service.
Southwest Regional Office.
http://swr.nmfs.noaa.gov/hcd/caulerpa/factsheet203.htm
Fletcher WJ, Jones B, Pearce AF, Hosja W. 2007. Western
Australian Department of Fisheries. Environmental and biological aspects of the
mass mortality of Pilchards (Autumn 1995) in Western Australia.
http://www.fish.wa.gov.au/docs/frr/frr106/index.php?0401
Whittington RJ, Chong R. 2007. Global trade in
ornamental fish from an Australian perspective: The case for revised import
risk analysis and management strategies. Previews of Veterinary Medicine. Epub ahead of print.
http://www.citeulike.org/user/sarahferriss/article/1296825
Wikipedia. 2007. Tasmanian giant freshwater
crayfish.
http://en.wikipedia.org/wiki/Astacopsis_gouldi
AQIS ISPM15 Frequently Asked Questions:
http://www.daffa.gov.au/aqis/import/timber/ispm-15-faq
http://www.daffa.gov.au/__data/assets/pdf_file/0017/114236/ispm15.pdf
Ziemann DA. 2001. The Potential for the
Restoration of Marine Ornamental Fish Populations through Hatchery Releases. Aquarium
Science and Conservation. 3(1-3): 107-117.
Images of AQIS
officer Melissa Danielse with a red piranha.
Photo’s by Peter
Watkins, courtesy Australian Quarantine and Inspection Service
by Steve Reynolds
In my article
titled “Even More Nudibranch Discoveries”, published in our March 2007
Newsletter (No.341), I mentioned the discovery of a Little Umbrella Shell, Tylodina
corticalis, by Dennis Hutson.
(As I said in my
article, Tylodina corticalis is not a nudibranch though. It is an
opisthobranch. Opisthobranchia is a Subclass of gastropod molluscs. Bubble
shells, sea hares, side-gilled slugs and nudibranchs are all opisthobranch
slugs.)
Dennis had found
the tiny yellow slug-like creature during our dive at Port Stanvac Dump in
November 2006. It is called the (Little or Small) Umbrella Shell due to the
limpet-like shell on its back.
There are four
photos of Tylodina corticalis in Neville Coleman’s “1001 Nudibranchs”.
These are all on page 135 (in the opisthobranch section of the book – page 117
on). Although Tylodina corticalis is classed as a slug, Neville Coleman
calls it the Small Umbrella Shell. The first of his four photos on page 135 was
taken at Glenelg in SA in 1971 (during Neville’s famous Australian Marine
Coastal Expedition – the biological fauna survey photographing and recording
the marine life of Australia’s 64,000km coastline- between 1969 & 1973). It
was a 20mm specimen and was photographed on a (red?) sponge at 10m.
(Dennis’s
specimen would have been at a similar depth at the Port Stanvac Dump.)
Its habitat is
said to be rocky reefs and its range is given as WA to Queensland. Two of the four
photos were taken at Lord Howe Island over 13 years apart (October and
January). A specimen photographed in Moreton Bay, Queensland was taken in May
1994. Neville’s specimens were all between 20 & 30mm in length. They are
said to be diurnally (daytime) active and feed on sponges. They lay a yellow
egg coil on the reef. The book “Australian Marine Life” by Graham Edgar says
that Tylodina corticalis is an opisthobranch (sea slug) from the Family
Tylodinidae. It describes the creature as having “a flattened limpet-like shell
into which the animal can just withdraw”.
Here are a few
more facts about Tylodina corticalis taken from “Australian Marine
Life”:-
They are said to
reach a length of 100mm.
They occur on
moderately exposed reefs down to 60m.
Their distribution
ranges from WA to southern Queensland and around Tasmania. Although six species
are known from the Tylodinidae family, this is the only one that occurs in
Australia.
It is said to be
widely distributed through southern Australia but not abundantly.
It feeds on the
yellow sponge Pseudoceratina sp.
It is also said
to “very rarely (be) seen outside the autumn months”. Our dive, however, being
on 18th November, was at the end of the spring season. Dennis Hutson
was able to take a few photographs of the Little Umbrella Shell at Port
Stanvac.
One of Dennis
Hutson’s photos of the Tylodina corticalis found at Port Stanvac Dump,
SA 18/11/06
We thought that
it was a rare sighting but later discovered that other photographers such as Michael
Matthewson and David Muirhead had also found specimens.
The January 2007
issue of the SODS newsletter (SODS News Vol.14, No.1) featured a photo of a Tylodina
corticalis specimen taken by Michael Matthewson. He says the picture was
taken at Second Valley on 28th January 2005. That puts the sighting well in to
the summer season.
One of Michael
Matthewson’s photos of the Tylodina corticalis found at Second Valley,
SA 28/1/05
Michael’s photo
was featured in the “Who Am I?” section of the SODS newsletter. The ‘answer’
part of the section described Tylodina corticalis as being “bright
chrome yellow with a wide foot and the shell is oval-shaped and covered by a
thick brown protective layer with strong radial ridges”.
I then received
a photo of a Tylodina corticalis specimen from David Muirhead. When I
contacted David, he sent me several more photos of the specimen along with
these details: -
“All these
images were taken in a blue dive-gear tub on the Ngerin’s deck on
26-05-06. I'm unsure which expedition diver actually collected the sponge
and then noticed the mollusc on it. It may have been Shirley Sorokin (the
sponge expert) herself, or her dive buddy or another diver on her behalf. It
was found at approx. 5m depth in Groper Bay at Flinders Island in the
Investigator Group, SA. I did not participate in that dive so I was pleased to
offer topside help with photographic record.”
One of David
Muirhead’s photos of the Tylodina corticalis found at Groper Bay at
Flinders Island in the Investigator Group, SA 26/5/06
I found out
through Heather Bird that one pair of divers had seen the Little Umbrella Shell
at both Second Valley and Seacliff Reef. SODS President Brian Spalding had seen
one between the swimming pool and the jetty at Edithburgh on 3rd
March 2007.
Below is a table
summarizing the above sighting dates: -
Date
|
Location
|
|
28 January 05 |
Second Valley |
|
26 May 06 |
Flinders
Island |
|
18 November 06 |
Port Stanvac |
|
3 March 07 |
Edithburgh |
The dates in the
above table indicate sightings through spring, summer and autumn at locations
on the Fleurieu, Yorke and Eyre peninsulas.
(Heather
published the first draft of this article in the March 2007 SODS Newsletter
(“News For SODS” Vol.14, Issue 3) so I have re-written it for publishing in our
own newsletter.)
My thanks to Dennis Hutson, David Muirhead and Michael Matthewson for
providing me with their photographs of the Tylodina corticalis specimens
that they found. Many thanks also go to Heather Bird for her assistance.
REFERENCES:
“1001
Nudibranchs” by Neville Coleman, Underwater Geographic P/L, 2001, ISBN
0947325255 – mlssa No.1050.
“The Little Umbrella Shell, Tylodina
corticalis” by Steve Reynolds, “News
For SODS” Vol.14, Issue 3, March 2007
“Even More Nudibranch
Discoveries” by Steve Reynolds, MLSSA Newsletter March 2007, No.341.
“Australian
Marine Life” by Graham J Edgar, Reed New Holland, 2003, ISBN 1 876334 38 X – mlssa No. 1053.