This is the MLSSA Newsletter, the monthly publication of the Marine Life Society Of South Australia Inc. Our Society is active in trying to protect our marine environment and this Newsletter usually contains articles about marine life and the marine environment.
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This month's meeting will be held at our usual venue, the Conservation Centre. It will be held on Wednesday 16th September and will begin at 8 pm sharp. Our guest is to be the Minister for the Environment and Heritage, Dorothy Kotz, who has made herself available to answer our questions on the Environment. This will be the first item of the evening. The General Meeting will follow after the tea break.
We hope as many members as possible will take this opportunity to attend with questions at the ready.
As mentioned in the August Newsletter this art display is being presented by the SA Museum. It is a splendid marriage of Science and Art. The display is to be found in the small room that used to house the Egyptian display. Margaret and I attended the first night and were very pleased to see so many familiar faces on what was a very, very wet evening. The room contains not only the splendid pictures by Sue Stranger but a display of local marine invertebrates and flora. The exhibition will continue until October 9th and I urge everyone to pay it a visit.
Philip Hall
The August Meeting was held at the Star of the Sea School at Henley Beach.
The general business of the meeting included discussion of the large amount of general and E-mail correspondence. The latter included questions from Seattle Aquarium on the keeping of Seadragons and a request from a Russian for information on the same topic.
A letter from Lynda Walsh of Redpath Technical Services thanked us for our assistance with their Infrared Search Project (see the item below ) and she also offered to give us a talk at a General Meeting.
Steve Reynolds has given up his position as SDF Rep and the meeting agreed he would be replaced by Chris Hall.
After the break, Tim Hoile who is in charge of the Discovery Centre, took us around and explained the working of the Centre. We were impressed by the entire set-up and were fascinated to learn the details of the Educational programme which is underway.
Philip Hall
The mother of MLSSA member Jonathon Walsh recently approached us through Ralph Richardson asking for assistance with a rather special project. Lynda wanted volunteers to float in the sea so that Infrared photographs could be taken of them. This was to be part of a presentation to the Indonesian Government on the subject of the use of Infrared imaging to assist in the rescue of people in, or on, the ocean in wooden boats. Unfortunately such a boat was not available in the short time span available, so------
A few days later Phill McPeake and Ralph donned wetsuits and entered off the ramp at the end of Henley Jetty, much to the disbelief of several very inquisitive fishermen. I let out a float on nearly 100 metres of line and they both bobbed about whilst the Seeker aircraft flew over several times taking the photographs. The weather was not good as there were several light showers but we got the job done.
Phill was hauled back whilst Ralph, who had donned full dive gear went to the bottom, but then encountered 50cm visibility and soon found his way back to the entry platform using his safety line as a guide.
Philip Hall
I maintain my own library of diving and boating books that may be of some assistance to Society members. I also keep files on these two topics plus files on wrecks, wreck sites, bottles, marine life, reef locations, aquatic reserves, first aid, fishing, jetties, boat ramps, pollution, organisations, events, etc, etc... I manage to keep up with developments concerning scuba diving as a long-term member of the Scuba Divers Federation committee. Next is some information about diving in West Lakes which I recently passed on to the SDF.
Scuba diving in West Lakes is only allowed with the written permission of the City of Charles Sturt. The council are the managers of the lake which comes under the jurisdiction of the Department of Transport. Permission to dive will, however, only be granted when a copy of public liability insurance for $10,000,000.00 is supplied to them. Even then, the dive cannot clash with other activities which are always happening on the lake. It would be extremely dangerous to dive without permission and risk a possible clash with other activities. High levels of toxic algae often occur in the lake and prevent any form of swimming there at times. Permission to dive will not be granted during high levels of toxic algae. Any person or group receiving permission to dive (with $10m insurance cover) will be advised when the lake gates are to open and close. They will be told to not swim after heavy rain occurs, to avoid swimming near all stormwater inlets, to remain on the southern side of the buoy markers near the outlet gtes, to obey all Transport SA Marine Safety Section regulations and to obey instructions on signs and white markers that indicate the swimming area in relationship to the inlet near Inlet Reserve. The gates operate automatically depending on the level of the tides. e.g. gates are closed at low tide occurring at 0945 hours and would open around 1200 hours with high tide occurring at 1600 hours. It is therefore necessary to ascertain the tide times before diving.
Steve Reynolds
Diving Officer 1998/9
In my "News in Brief" report in our May 1998 Newsletter I stated that the Whyalla Sports Diving Club was trying to protect cuttlefish breeding grounds. A report in the Advertiser later reported a group of people taking more than 230kg of cuttlefish from a closed area near Port Lowly (Lowly Point?). Another report in the Advertiser then said that huge numbers of cuttlefish were being caught by recreational anglers in the Whyalla area, prompting the introduction of a bag limit for the species. As reported in the July Newsletter the Fisheries Department has introduced a bag limit of 15 cuttlefish per day and a boat limit of 45 per day. The area bounded by the Santos fence, the Whyalla jetty and the lighthouse has been closed to cuttlefish fishing. The Advertiser of 5/6/98 said that MP Ms. Lyn Breuer called for cuttlefish fishing in the Point Lowly (Lowly Point?) - Black Point area of Spencer Gulf to be banned. Ms. Breuer said that the Whyalla community was deeply concerned about the exploitation of cuttlefish during their breeding season. There has been a massive increase in the commercial catch of cuttlefish over the past three years. That increase has occurred without the benefit of a management program based on scientific evidence. The next day's Advertiser said that Fisheries officers were actively policing the recently introduced cuttlefish bag limit. It didn't claim that the boat limit was being policed though! The new limits (15/bag,45/boat) had been introduced on about 25th May. It was claimed that several anglers had been caught exceeding the new limits by the 6th June. There was an article titled "Cuttlefish, Too Little Too Late" in the SA Regional Ripples Vol.5, No.1 (the insert in "Waves"). It had been compiled from a media release from Tony Bramley, President of the Whyalla Sports Divers Club.
Steve Reynolds
Library Officer 1998/9
In our January 1992 Newsletter (No.174) I stated that the "Songvaar" sank on the same day as the "Titanic" ("More About Wardang Island's Shipwrecks"). The "Songvaar" was considered to have sank on 14th April 1912, just like the "RMS Titanic" but it wasn't quite that simple. That was the day that the "Songvaar" sat on a fluke of her own port anchor when the tide ebbed. The anchor fluke pierced the hull on the starboard side causing her to sink slowly. A salvage team tried for one year to refloat her but she defied all attempts. She just sat there for another seven or eight years until she heeled over in 1920 during a storm. She then had to be demolished with explosives so that she would not be hazardous to shipping. The remains are said to be the most extensive of the eight shipwrecks that form the Wardang Island maritime heritage trail. Society members dived on the wreck over Easter 1981. Phill McPeake was the Diving Officer then. He described the wreck as follows:- "What a sight! The sea was flat and the visibility was at least 50 feet. There below us 40 feet down stretched out a magnificent sight of a great hull at least 100 feet long, laying on its side with its huge steel masts protruding far out on one side. The fish life was extensive and in large numbers and a great variety of growth covered the entire wreck." Our members collected six species of fish from the site for the SA Museum's survey of fish fauna at that time.
Steve Reynolds
Phill McPeake has been researching the possibility of establishing a marine tank with a live sand filter instead of our usual undergravel filter system.
This all began when he noticed a strong growth of filamentous hair algae in one of his tanks and decided he would like to prevent its formation naturally.
A while later he was in Aquarium City at Christies Beach and saw the type of filter system they had installed for their Tropical Marines. It was a live sand filter system. He enquired about its construction and then spent some time on the Internet. The following has emerged:-
Basically, as we now know, there are three main elements; water in the aquarium, the sand layers of the bed, and the space underneath which is referred to as the plenum.
Live sand systems utilize a void space or plenum underneath the substrate. It is believed that this stagnant water area helps to set up an oxygen concentration gradient throughout the substrate. Oxygen levels start at saturation at the surface and gradually decrease as the depth of the substrate increases. This creates an area low in oxygen or an anoxic space in the sand. The idea is that the water space underneath the sand helps the substrate prevent the oxygen level from either rising too high or going totally anaerobic. The plenum also causes diffusion of various chemical ions into the water.
Anaerobic conditions would create Hydrogen Sulphide which is totally undesirable and would result in the stressing of the tank life. The system is believed to dissolve calcium, magnesium, and strontium at natural levels within the tank with no supplemental additions. It has also been suggested that the plenum, or void space, acts as a nutrient sink preventing some undesirable nutrients from entering and dissolving in the water column. Live sand filtration also depends on various sifting and burrowing organisms to maintain the oxygen gradient within the sand and to lift heavier detritus into the water column rather than fouling up the sand bed.
Live sand beds with a plenum area are very easy to construct and install. All that is needed is something to make a support for the sand to sit on. This can be an old undergravel filter or the usual light grid. Cut the material so that there is a 2cm space between the edge of the material and the glass panes of the tank. This will make the plenum area invisible to the outside world and will also prevent light entering. This latter point is important as a darkened plenum will operate better. PVC tubing is cut to various lengths and siliconed onto the bottom of the plate at random positions to ensure the plenum will be at least 2cms off the bottom, and to strengthen the plate when sand and rocks are put in on top of it. You will need fiberglass screening material to lay over the plate with the edges turned down. This is to prevent sand from getting into the void space. Sand in this area would lower the efficiency of this method. On top of this screen you should lay a 2cm layer of coarse sand high in calcium carbonate and strontium carbonate. You then put another layer of finer screening above this sand layer and install 5cm more of fine live sand. You can also use totally live sand for the entire filter bed if you wish.
The newly installed live sand bed will take a while before it begins to work properly. You must provide strong water motion in the tank and sand sifters and stirrers. Crabs and snails will be very beneficial to the system in general. Periodic manual stirring of the sand's upper layer will also help to keep the live sand in good shape. This type of system is not static. The sand dissolves and will need replacement. You may need to add new sand about every six months. This is normal and is part of the maintenance schedule. As the sand dissolves calcium, magnesium, and strontium ions are released into the system for the benefit of the hard corals and clams.
Much of what enters the plenum is by diffusion. Reaction rates of elements are assumed to be by rate limiting factors. Take oxygen for example. If the plenum has direct access to the water above the sand bed via a hole or torn grid, results would have to be logically altered.
In summary let's start at the bottom and go back to the top adding some very general dimensions:
salinity = 30 parts per thousand (plus or minus 2 parts per thousand)
pH = 8.2 (plus or minus 2)
temperature = 16 degrees C (plus or minus 1 degree C)
NO2 = 0
NO3 = as close to zero as possible
calcium = 400 mg/l (average)
It is very important to have complete circulation. A high volume pump and well designed placing of rocks will be important.
Strong lights are essential.
Then careful stocking of the tank begins.
Acknowledgements
We have obtained information from various Internet sites including:-
Live Sand and Jaubert Reef Systems by Luis Mercado
Natural Nitrate Reduction Report by Gary V. Deutschmann, Sr.
Reef Aquarium Farming News, Page 3
The Generic Sand Bed System by Sam Gamble
Phill McPeake
Philip Hall
Friday 24th of July saw me heading out to Reef Point which is on Aboriginal Land at Point Pearce with a good friend of mine. He has a part time position working for a fellow who has leased land on the Point to start an abalone farm. The actual farm is to be found in a 30 X 30 shed, where sea water is pumped directly from the sea into the many round tanks, that are located both in the shed and outside.
Each tank is approximately one metre in diameter. Water is slowly run through this tank and is then released through a centre drain which sits approximately 8 to 10 centimetres off the bottom of each tank. These drains have a small cage set up to prevent the abalone from escaping down the tube, which they have been known to do.
Small abalone which escaped in the past into the pipe system are known to have grown quicker than those in the tanks. The reason for this may be the lack of light in these tubes. The owner now deliberately allows a certain amount of abalone into the tubes so that when he cleans the tanks out he can also harvest the abalone in the pipes.
The food that is fed to the shellfish is dried kelp, which they seem to grow well on. Only a small amount is added each week to keep them going. When the abalone reach a size of about 7cm, they are harvested and shipped off to the Japanese markets. The price for each abalone is about $5.00 but are subsequently sold for $44.00 on the Japanese market. (Not a bad profit hey!). So if you take a trip to Japan do not ask for an abalone dish as it could cost you $100.00.
Another project the grower is working on is how viable it would be to grow sea urchins for the Japanese market and he is experimenting with this at the moment.
After this farm is set up it will be handed over to the Nurrunga Aboriginals to run for themselves.
One family of Aboriginals has set up an oyster growing farm on Wardang Island and are doing very well out of it. So it looks like it could be a positive enterprise for the local aboriginal population.
At the moment it looks as if the Narrunga TAFE will be running an Aquaculture Course within the next three weeks.
Ron Bellchambers
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