Release Weight to Improve the Survival of Released Reef Fish

The contents of the DVD:- "Using the Release Weight to improve the survival of released fish" can be viewed directly or downloaded and saved to view later from Recfishwest's Release Weight DVD page

A tagged West Australian Dhufish
fitted with a release weight
ready to be returned to the water.

The release of marine fish has become increasingly important to recreational anglers. Fisheries regulations and management tools such as size limits, bag limits and closed seasons as well as a stronger conservation ethic has resulted in more fish being released.

Many reef species, such as dhufish and breaksea cod, are susceptible to pressure related injuries called barotrauma when raised to the surface from depths of around 20 metres or more.

Pink snapper with
inflated abdomen and
distended intestines.

Barotrauma results from the expansion of gases in the swim bladder and other organs when fish do not have time to adjust to the rapid changes in water pressure as they are pulled to the surface. The physical effects of barotrauma can be seen in the form of inflated abdomen, bulging eyes, stomach pushed into the mouth and distended intestines.

Undersize or unwanted fish that are returned to the water showing signs of barotrauma may often have difficulty swimming and returning to the bottom. Such fish may be unable to reach a depth where water pressure would allow their swim bladder to revert to the normal size and therefore may require special handling to improve survival.

Many anglers have been concerned to see released fish drift away on the surface and wanted a simple method to help survival.

The Release Weight

Breaksea cod with
stomach in mouth
and bulging eye.

This device essentially comprises of a weighted barb-less hook. The release weight can either be connected to an existing fishing rig via the clip or used on a rod and reel or hand-line specially set aside for releasing fish.

The Release weight is attached through the lip of a fish to be released, lowered into the water and dropped back to the reef. The weight is then easily detached from the fish by a tug on the line when it reaches the bottom, leaving the fish back at the depth it was captured, recompressed to the original pressure and near the fish's places of cover.

In many cases the fish recovers and gets off the barbless hook on the way down.

Release
Weight

Using the Release Weight

The release weight is simple to use. The complete release procedure can be performed by one person for small fish while larger fish will need the co-operation of two people. Single operator - small fish only

Attach the release weight through the jaw of the fish. Hold the fish in one hand and the rod or hand-line ready for free spool in the other. Place the fish into the water headfirst and let the attached line run free as the fish is released.

A West Australian
Dhufish heading
for the bottom
on a release weight.

Two person approach

Whilst one person supports the body of the fish the other can fix the weight in place and then operate the rod or hand-line as the fish is released (top photo).

It is important to get the fish as deep as possible before it gets off the weight. Beware of any sudden jerk on the line while the fish is descending as this may dislodge the weight from the fish before it has reached the bottom.

Advantages

• Gets fish back to its habitat fast.
• Re-pressurises the fish to lessen the effects of barotrauma.
• Reduces predation through decreased surface and mid water exposure time.
• Showing signs of increased recapture rates for several species.

Fish Handling

• Keep fish out of water for a minimum time possible.
• Work fast but without haste.
• Always use wet hands or a wet cloth.
• Place fish on a wet surface. Avoid hot dry surfaces.
• Avoid contact with gills and eyes of fish and try to keep shaded (particularly Dhufish).
• Fully support the body of large fish at all times to avoid organ damage.

Some of the species for which the release weight can be used:

West Australian Dhufish
Pink Snapper
Breaksea Cod
Mulloway / Northern Jewfish
Red Emperor / Coral Trout
Baldchin Groper and other Tuskfish
Various Cod species
North-west Snappers (Emperors)

Website links about releasing fish and survival

The contents of the DVD:- "Using the Release Weight to improve the survival of released fish" can be viewed directly or downloaded and saved to view later from Recfishwest's Release Weight DVD page

Fascinating footage highlights benefits of Release Weight.

Collaborative tagging program and research - more about the West Coast research results mentioned in this video.

Brochure on the Release Weight formatted for printing on two A4 pages (217 kilobyte PDF file)

Info-fish website Released fish survival - Gently does it (link opens in a new window)



FRDC "Gently does it" media release (link opens in a new window)

National Strategy for the Survival of Released Line Caught Fish (1.1 Megabyte PDF file - link opens in a new window)



This page last updated on 10 July 2008.