by DPI Victoria
A Department of Primary Industries (DPI) study has confirmed the belief of many anglers that, if handled correctly, most black bream and snapper survive after release.
When releasing undersize fish, many anglers assume that all or most of them survive. It is important to know if this assumption is correct to help determine the effective management tools, such as size and bag limits, in protecting fish stocks from the effects of fishing.
Fisheries scientists investigated how many released black bream and snapper survive post release and ways to improve their chances of survival. A group of expert volunteer research anglers were enlisted to catch and release bream and snapper under a variety of conditions.
The study found that many factors could affect the survival of hooked and released bream and snapper, but the most significant one was whether the fish were shallow-hooked (mouth) or deep-hooked. Researchers found the mortality rate among mouth-hooked bream and snapper was about 1 to 2 per cent compared to 22 to 23 per cent for both species when deep-hooked.
Rod fishing trials were also undertaken, comparing fishing with a tight line to using a slack line. A slack line gave the fish a greater chance of swallowing the bait before the angler reacted and hooked the fish. This meant there was a greater chance of the fish being deep-hooked and not surviving.
Further work is needed to determine the proportion of shallow-hooked to deep-hooked fish in Victorian recreational bream and snapper fisheries, but it is anticipated that overall survival of released undersize fish would be at least 85 per cent.
As a result of the study, DPI fisheries scientists recommend that anglers:
- Fish with a tight line because this leads to more shallow-hooked fish;
- Fish with a larger hook because this reduces the chances of deep-hooking undersize fish; and
- Cut the line if a fish is deep-hooked instead of removing the hook.
This study was jointly funded by Fisheries Victoria, the Recreational Fishing Licence Trust Fund and the Fisheries Research and Development Corporation. It was conducted as part of the National Strategy for the Survival of Released Line-caught Fish.