EELS
Rob McCormack
There are 4 different species of eels you can find in Coastal NSW. Only 2 of them are of interest to us and these are the most common types. Basically we have two types of eels, Long Finned (Anguilla reinhardtii) and Short Finned (Anguilla australis). The main type we do is the Long Finned as this is the one that receives the highest price and demand in this region.
Long Finned eels can be identified by the (top) dorsal fin which is longer than the short finned eel. The long finned eel's dorsal fin starts well before the anal fin (bottom) which starts just after the anus (vent).
On the short finned eel the dorsal fin (top) starts just a little before the anal fin (bottom). Short finned do not grow as large as the long finned. Under 10kgs.
Long Finned eels are fascinating animals. They start their lives as eggs in the Coral Sea off New Caledonia and or New Guinea in deep water 300 to 3000 meters down. It's not exactly known as eels are still a mystery to most researchers as their life cycle has not been repeated in the laboratory as yet. From there they drift with the currents, then hatch into larva drifting and swimming with the currents till they hit the East Coast of Australia. When these baby eels drift down the Coast line of Australia they enter the river systems and migrate upstream. When they first enter the rivers they are called glass eels as they are very small and clear (See Through). Once they enter fresh water and start feeding they become pigmented and darken in colour and are called elvers. These glass eels and elvers migrate upstream in enormous numbers at the right time of year.
It seems unknown why they enter some river systems rather than others but it is supposed that there is some sort of genetic imprinting in the eels from their parents to return to the area their parents came from. Also rainfall is an important factor. Elvers have an instinct to migrate upstream and need flowing water for this to occur. Drought conditions see a dramatic drop in recruitment of elvers into drought affected river drainage basins.
As a general rule it is the male eels that stay in the salt/brackish water and usually the female eels which migrate well upstream from the salt water and are the ones that enter your freshwater rivers, creeks and dams. Eels are a major problem for people who want to use farm dams for aquaculture. When your farm dam fills and then overflows the overflow water may only be a small trickle through the paddock but eventually that water hits a creek or steam with eels in it and they can scent/feel/smell that dam water which is different to the general paddock runoff water and follow that scent back to your dam. Generally they will stick to the water course but if an obstacle is in their path they will go overland around the weir/waterfall etc. They can survive quite well out of water in moist conditions. They may be only small elvers only 100mm long but over time they will grow into massive eels. Generally these eels will stay from 10 – 30 years in your dam and then in flood conditions migrate back to sea to breed and then die. Long finned eels have been known to grow to over 80 kgs in size and live for 60 years. When these adult eels migrate back to the sea they actually change shape. The head flattens and the eyes broaden around the head.
Eels are extremely tough; 10 years ago we did an experiment on a 2 kg eel to see how long it could survive without food. We kept this eel in a 1000 litre tank in good quality water with aeration for 18 months without food before it started getting ulcers and we took pity on it and gave it a feed, cleaned it up and then let her go.
In a normal farm dam type situation it usually takes the small elvers at 100mm long approximately 3 years to become a major predator in your dam. The 3 year olds are in the 250 – 350 gram range and rapidly grow in size from then on and if it's a yabby dam can completely eliminate all yabbies from the dam as there is nowhere a yabby can go that an eel can not. The yabby of the Cherax variety with a thin smooth shell has no defense against eels and are easy prey. The Eustacus type with a thick, strong and spiny shell can co habitat with eels. It's not as critical with native fish as most Australian native fish are fast and smart so most can mostly avoid eel predation. However the eels will eat the same food as the fish so the more eels the less food available for your fish.
In a yabby dam eels are not a problem until they are over 200 gram in size. That is at that size that they start making a noticeable impact on your yabby population. Most people on the Eastern Drainage who put in a new farm dam and stock with yabbies will usually have a great yabby dam for the first 3 years them year 4 notice a major decline of numbers and by year 5 have no yabbies at all. The dams at most risk to eel infestation are those with a large catchment which quickly fill and overflow regularly. Those dams with small catchments and intermittent overflows are less likely to be heavily infested with eels.
Eels can be captured quite easily from farm dams. Set lines are a traditional way. Just 3 – 4 meters of strong fishing line tied to a tree or stump on the bank with a heavy duty long shank hook ( Number 2 or 4 ) and a piece of fresh meat or fish for bait. Eels are a predator which hunts in the shallows of your dams at night. Just bait the lines (6 or 8 ) up in the afternoon and leave out overnight. Check in the morning and usually you will find the eels have caught themselves. Eels are very strong and smart, they will tangle themselves under rocks and snags etc so make sure your set lines are only short. They also tend to twist and roll which can but extreme pressure on your system so use heavy duty hooks and line.
Traps are also good eel catchers. At Port Stephens we use a large black opera house type trap which we bait with pilchards. This works very well as pilchards are excellent bait as their strong oily smell attracts eels from a long distance. These type eel traps are on sale at RBM Aquaculture. We also use fike nets from time to time and these also work very well. For our commercial harvest of eels we use a home made eel trap approx 600mm square and up to 3mtrs long. These traps catch around 60kgs/trap/night if the eels are present.
We grow mostly long finned eels here as in NSW this is the one with the ready market and high demand. In Victoria and Tasmania they tend to produce more short finned eels. Caution should be taken if you are purchasing glass eels as you may well be purchasing the wrong type. Don't get short finned or you may find there is not a ready market for the final product in NSW.
Long finned eels sold by us are sold to an exporter who then sells them to Asia. We just have a 10,000 litre tank here with our eels in it ready for pick up. The exporters have their own transport trucks and come out to our farm. We load the eels up into fine net bags at 30 – 50 kgs per bag, these bags are then weighed and the eels then emptied into the live transport tanks on the back of the truck. We usually do loads of about 100 kgs per go. Only long finned eels are taken and need to be over 650 gram in size. The bigger the better. The exporters pay you at time of pick up at a rate dependent on time of year of $11 up to $15/kg. Small eels and short finned eels they will take off your hands but at $3 - $4/kg.
Both these 2 species of eels have excellent aquaculture potential and many farmers are starting to farm eels. Because of the difficulty of breeding eels in captivity (has not been done as yet despite millions of dollars spent in research in the Northern Hemisphere) all glass eels for culture are captured from the wild. In NSW the NSW Fisheries department is unsure of the glass eel stocks available so has capped the collection of glass eels at 300 kgs/year. To date this supply has been unreliable. Another source of glass eels is to get them from interstate where more are available regularly. There are from 3000 to 6000 glass eels per kilogram.
Eels can be grown intensively in recirculation systems at up to 100kgs/m³ but generally at around 60kgs/m³. They can be grown intensively in ponds at 7,000kgs/ha or just extensively at 500kgs/ha. Eels are cannibalistic and grading to separate the large from the small is wise. In the wild we work on a catch rate of 300kgs/ha of larger over 650gram eels. So if you have farm dams this is what you can expect to harvest from natural stocks in this region.
Many people are looking at eel farming these days due to the relatively high prices paid per kilogram. You can purchase small eels from professional fisherman at around 200 – 300 gram in size and from $2 - $4/kg. These eels can then be trained onto pellet feed and fed daily in special earthen eel ponds can reach a weight of 1kg in 12 months. This is the easiest method of growing eels as using glass eels is a very labour intensive method. 200gram eels can be easily trained onto Silver Perch or Barra Pellets without any great effort. Keep them well fed in good quality water and cannibalism will be greatly reduced.
We do most of our eel fishing over winter at Port Stephens. This is not the best time to do it as eels are cold blooded animals so as the water temperature drops their metabolism slows so they don't need as much food or feed as much. However if the water is over 15ْ C then eels can be captured in our traps. We usually fish over winter as we usually receive a better price then and we usually have a bit more time available. We sell the larger eels we capture and keep the smaller ones and grow them up in a pond. We just capture eels as we get spare time and store them in a tank until we have enough for either stocking a pond or for sale.
The only problem with holding eels in winter is that their metabolism is going slow so they are more susceptible to infections. In the traps when captured they run their head along the trap looking for a way out and can loose their slim covering which can let infections attack the eel. We have had big trouble with eels in winter in our holding tanks in the past with fungal infections. We have overcome the problems by holding them in tanks with a prophylactic treatment of hydrogen peroxide and colloidal silver ions in the water. This has been 100% effective and no fungal outbreaks occur now.
Macca
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The following is part of a letter to NSW Fisheries on Eel Bycatch. Eels caught on most aquaculture farms are only allowed to be destroyed not sold. RBM Aquaculture is one of the select few who have an eel bycatch permit. NSW Fisheries is not issuing any new ones and this letter refers to that issue and the attempt by the NSW Aquaculture Association to have the regulations changed to allow all aquaculturalists to sell their eels and not waste this valuable recourse. The NSWAA will continue the fight on your behalf to allow you to capture and sell the eels from your properties but at the moment it is the NSW Commercial eel fishers who are refusing to allow you to do so. They believe that all eels in NSW belong to them and they should get your eels. It's a piss poor attitude but we will fight on.
6408 PACIFIC HIGHWAY, NORTH ARM COVE NSW 2324.
P.O. Box 3, Karuah. NSW 2324.
PHONE (02) 4997 3002 FAX: (02) 9688 4645 Email: nswaqua@nobbys.net.au
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Aquaculture on the Eastern Drainage of NSW is an activity beset by numerous problems and a major one of these is Eels. These Aquaculture Facilities for both fish and crayfish require large volumes of water in storage reservoirs, to provide a constant supply of water to commercial growout ponds. The majority of these storage dams are located on properties in positions that collect the greatest amount of surface runoff, therefore ensuring that water is not wasted. However, as a general rule the Eastern Drainage area of NSW is subject to storm events and extended wet period which sees these storage dams fill and then overflow. Once these storages overflow they are subject to infestation by both short and long fined eels.
Eels are a major problem as their instinct is to migrate upstream and live in freshwater dams. Water that overflows from a dam may travel across a paddock for many kilometers before actually entering a creek or river where eels are present. This dam water smells, tastes or feels different to regular run off and eels have the ability to sense this and will follow the sent back to the dam despite obstacles obstructing them.
Water storage dams are not the only dams subject to infestation, both crayfish and fish growout ponds have trouble. In NSW most extensive yabby ponds for example have a 600mm high fence surrounding them to prohibit eels from entering the pond by traveling overland. However, they still must allow excess rainwater to exit the pond by an overflow pipe. On my farm my ponds are gravity drainable by 6 inch PVC sewer pipe. This is a pipe that goes from outside the pond, under the pond wall into the bottom of the pond and a concrete sump and then to a 90 degree bend and 1.2 meters of vertical pipe which sets the water height.
When this pond overflows and water vertically drops 1.2 metres down the stand pipe. Glass eels are attracted by the overflow water, and are quite capable of slithering up that smooth vertical internal pipe surface and entering the pond.
Fish ponds are in even greater danger as they do not have any barrier fences surrounding them and eels will travel overland seeking water if the dam they are in is drained. This is where infestation of water storage reservoirs becomes a problem. When you extract water from your storages to fill your ponds and the water level in the dam rapidly drops eels will abandon the dam and slither overland (Potentially into a growout pond). We can sit there all day and shoot eels as they slither up the banks but that is time consuming and many times it is drained overnight etc. Additionally we pump water from these reservoirs and it is quite common for a glass eel or elver to be sucked through a 5mm filter, go through the pump and 1000mtrs of pipe and come out the other end in perfect health in a growout pond.
Eels may only be in the glass eel or elver stage when they infest dams but over the years they grow to be a major problem. Many yabby ponds are infested with glass eels during a storm event and problems do not become noticeable for 3 years as that is the time it takes for eels to grow to a size that yabbies do not like. Yabbies refuse to live in the same water as eels. Eels are the single greatest factor that has limited crayfish production on the eastern drainage. There is nowhere in a pond that yabbies can go and eels can not. Just 3 eels 600mm long in a 1000 square mtr surface area pond will eliminate all yabbies.
Fish are a better prospect as they will live in harmony with eels to some extent. However eels can eat fish and love fish food. We have all seen the pictures of a 100 kg eel which came out of a Silver Perch pond. Only a few fish left and one giant eel.
Eels also eat fish food so even if they are too small to eat the fish they will eat the food so need to be removed from the ponds.
Currently we are allowed to catch the eels, which we do and then destroy them. This is a gross waste of a resource. A large amount of time and effort is expended to capture these eels; to then destroy them is unprofitable.
The NSW Aquaculture Association Inc on behalf of its members proposes that the regulations on Eel Bycatch to be changed to allow these eels to be sold so the cost of capture and removal from ponds can be recouped by the Licensed aquaculturalists.
Permit holders wishing to sell eels captured on their properties should apply to NSW Fisheries to have their Permits altered to include Eels both short and long finned, and pay NSW Fisheries the appropriate permit alteration fee. Records of the amounts captured and sold to be kept and recorded on annual Production Returns to NSW Fisheries.
Actual amount of eels entering the market from bycatch would be small. Generally it would be only a few hundred kilos per farmer per year. In total across NSW we predict in the order of 5000 kgs per year maximum and this would be for the first few years and then reduce as initial stocks are removed.
Generally most eels would go to the exporters the same ones who handle the wild catch, we do not expect any impact on the wild catch fishers as the quantities involved are so small and the exporters would only pick up if they are in the area and if you have enough to make it worthwhile etc. We would also expect that eels may be sold to other outlets. For example if you are supplying fish or yabbies direct to a restaurant or the public, etc. then if they want eels and you have them, why not?
It has been suggested that limitations should be applied to restrict impacts on commercial fishers. Personally, I do not think that the quantities involved would be of any impact to commercial fishers, however, if a limit of kgs of eels per hectare of water is necessary than a figure of 350kgs maximum could be applied as nobody would reach that limit anyway. 350 kgs is the amount of eels we could expect out of the best eel dams we have commonly encountered.
Basically it's all been said. Aquaculture is a business fraught with problems and eels are very high on the list. A considerable amount of time and expense goes into eliminating eels from aquaculture facilities and currently we must destroy these eels, this is a waste of a valuable resource and we are requesting that the rules be changed to allow us to sell this bycatch. If you require further information or clarification please feel free to contact me direct. If you wish me to address a meeting of commercial fishers I would be happy to do so at your convenience.
Rob McCormack
President
NSW Aquaculture Association Inc.
For the last 5 years or more the NSWAA has been battling for NSW Fisheries to allow the sale of eels from aquaculture farms but the NSW Fisheries Department has ignored the pleas of the aquaculturalists and instead listened to the professional fishermen. The professional eel fishers believe all eels in NSW belong to them and that the aquaculturalists should catch their eels and give them to them. It's a pathetic attitude but what is more astounding is that NSW Fisheries who we pay to manage the industry listens to the commercial fishers and ignores us. At the moment the aquaculturalists find it easier to kill the eels rather than catch them and give them away.
This is a serious problem and one that hopefully some sense will prevail in the future. At the moment there are 5 stakeholders in the eel equation.
1. The aquaculturalists who have the eels and will spend the time and money to catch them if they can sell them.
2. The commercial fishers who believe all eels in NSW belong to them.
3. The ell exporters where all the ells are sold to whether from commercial fishers or aquaculturalists. They always want more as they can never get enough for their export orders.
4. The NSW Fisheries department.
5. The community as a whole.
With the current NSW Fisheries policy absolutely nobody benefits, the aquaculturalists don't make any money from dead eels, the commercial fishers don't make any money, the same for the exporters, fisheries and the community also get nothing.
Now it some intelligence prevails in the future and the regulations are changed to allow the sale of eels from aquaculture facilities then.
1. The aquaculturalists can turn a waste species into cash and make more money thus becoming more commercially viable.
2. The commercial fishers will be unchanged as the cant loose what they don't have.
3. The exporters will be happy as they can have a few extra people helping to supply them.
4. NSW Fisheries will be happy as more production from existing farms will make their production returns look better.
5. The community as a whole will be happy with the recycling of eels into food and money rather than land fill.
The NSW Aquaculture Association will continue to battle on your behalf, and hopefully in the not to distant future the regulations will change.