It is important to protect fish stocks by only taking what you need. You must not retain fish and other aquatic animals that are:
- under legal minimum length
- over the legal permitted length
- caught in a closure area or during a closed season
- excess to your daily personal bag or boat limits
- a protected species.
If your catch meets any of the above reasons, it must be immediately returned to the water unencumbered. All anglers are responsible for releasing fish in a way that ensures their best chance of survival, including the correct handling techniques.
Learn how to release your catch, and what to do for fish that are suffering from a depth transition.
Releasing fish
We recommend unhooking the fish while still in the water. If this is not possible, take these steps to keep the fish wet and minimise harm during release:
- Place the fish on a cool, wet surface and handle with wet hands to reduce damage to the protective slime on the surface of the fish.
- Depending on the circ*mstances, either:
- remove the hook from the fish's mouth
- cut the line close to the fish's mouth if it is deep-hooked in the gills or gut – trying to remove the hook in this situation will cause more harm to the fish.
- To return fish to the water:
- hold the fish horizontally and support its body when gently placing it into the water
- support larger species with a hand under the head and belly, to minimise damage to their backbone
- manually move the fish through the water if it does not swim off your hands – this may be needed to help fish that have been over-stressed
- if the fish was caught from a depth of 10 metres or more,use a release weight to release it.
Identifying barotrauma
Many bottom dwelling species are susceptible to barotrauma when caught from depths greater than 10metres. This is a pressure ('baro') related injury ('trauma') to fish.
Barotrauma is caused by gases expanding within the body because of the rapid change in pressure when the fish is brought to the surface. There are several signs of injury, with the most obvious being:
- hyperextension of the swimbladder that produces a swollen abdomen
- eversion of the stomach into the throat or out of the mouth.
The expansion of gas in the swimbladder can result in excessive buoyancy, preventing the fish from returning to depth on its own after release. This leads to sun damage and an increased risk of predation from sharks, birds, marine mammals, and other large fish.
How you can help
We strongly encourage recreational fishers to carry a release weight when fishing in deeper water. The weight brings the fish back to its depth of capture, which recompresses the gasses in its body and corrects the buoyancy. This is needed for returning:
- unintentionally caught or undersized Snapper
- other bottom dwelling species such as Blue Groper, Mulloway and Samsonfish.
A study undertaken by SARDI found that barotrauma-affected fish had a higher probability of survival with a release weight, compared to returning them to the water surface. Even if fish appear healthy, some succumb to their injuries hours after they are released if they are not assisted.
Using release weights
The release weight is most easily used by 2 people, where one person supports the fish and the other attaches the weight. It can also be used individually. Follow these steps:
- Support the fish and attach the release weight through the upper jaw. If possible, use the existing hole from where the fish was hooked.
- Place the fish in the water and then let it go.The retrieval line will run free, allowing the release weight to take the fish back to depth.
- Detach the release weight from the fish by stopping the retrieval line and briefly pulling on it. The barbless hook will slide out of the fish’s mouth and the release weight can be retrieved.
Best practice fish release video
Transcript
Transcript
[Jamie Crawford] When the need arises to release a fish, we’re all responsible for ensuring it is released in a way that provides the greatest chance of survival.
Snapper, like many other bottom dwelling species, are susceptible to barotrauma when caught from depths greater than 10 metres.
[Courtney Cheesman] Barotrauma is a pressure related injury that fish experience when reeled up from depth. These injuries are caused by the expansion of gases within the fish’s body, as a result, of the rapid change in pressure when brought to the surface.
There are a number of injuries caused by barotrauma including hyperextension of the swimbladder that results in a swollen abdomen, and eversion of the stomach into the throat or out of the mouth.
[Jamie Crawford] The expansion of gas in the swimbladder can result in excessive buoyancy, which prevents the fish from returning to depth on its own, and can lead to sun damage and increased risk from predators.
[Troy Rogers] A recent study led by SARDI and funded by the Fisheries Research and Development Corporation monitored the survival rates of released Snapper caught in South Australia’s gulfs using electronic tags.
The fish were captured at various depths up to 35 metres and released either at the surface or returned to their depth of capture using a release weight.
[Jamie Crawford] The study found that the severity of barotrauma increased with depth, which resulted in a rapid decline in the survival rates of released fish. Despite initially appearing healthy when released, some fish succumbed to their injuries up to 10 hours after they were returned to the water.
The study also showed that fish returned to the water using a release weight had a higher probability of survival than those released at the surface.
[Courtney Cheesman] Recreational fishers in South Australia are strongly encouraged to carry a release weight when releasing in deeper water, especially to assist with the release of unintentionally caught or undersized Snapper.
A release weight returns the fish to its depth of capture, which recompresses the gasses in the fish’s body and allows it to regain correct buoyancy.
[Troy Rogers] The most common form of release weight is a large sinker attached to an inverted barbless hook, which is fitted to a separate fishing rod or a heavy retrieval line.
These can be purchased from fishing and tackle stores around South Australia or made at home using a large sinker and a barbless hook.
[Jamie Crawford] There are a number of things that fishers can do to optimise the survival of released Snapper.
Firstly, fishing for Snapper in shallow water is the best option to reduce barotrauma and improve survival, given the strong relationship between barotrauma and depth.
Deep hooking, where the fish is hooked in the gills or stomach, can significantly impact post-release survival. This can be reduced by using circle hooks rather than traditional J hooks when bait fishing, or by lure fishing instead.
[Courtney Cheesman] When landing and handling a fish intended for release, it is considered best practice to be prepared before the fish is hooked by having the necessary tools and equipment readily available, such as a landing net, wet towel and pliers.
Reducing handling time and air exposure will optimise the probability of survival.
It is also recommended to use a knotless or silicon landing net to support the weight of the fish when bringing it to the vessel and placing the fish onto a cool, wet surface and handling with wet hands or gloves to minimise the removal of protective mucus.
You should also remove the hook from the fish’s mouth or cut the line close to the mouth if the fish is ‘deep hooked’.
[Troy Rogers] The release weight is most easily used by two people, where one person supports the fish and the other attaches the weight.
However, it can also be used individually.
The recommended approach is to support the fish and attach the release weight through the upper jaw.
Where possible, use the existing hole from where the fish was hooked.
Place the fish in the water and then let it go, allowing the release weight to take the fish back to depth.
[Courtney Cheesman] Let the retrieval line run free as the fish is released and then detach the release weight from the fish by stopping the retrieval line and briefly pulling on it.
The barbless hook will slide out of the fish’s mouth and the release weight can be retrieved.
[Jamie Crawford] By making small changes to the way that we handle and release Snapper, we can all optimise their probability of survival when released and contribute to the recovery of this iconic fish species.
