Reef fish feel the pressure

Fisheries researchers from the Northern Territory Department of Primary Industry and Fisheries (DPIF) have used underwater video cameras to highlight the effects of barotrauma on reef fish.

Barotrauma is the term used when gases expand in a fish’s body as it is brought up from the bottom. Many anglers would have seen the effects of barotrauma on fish, most notably the fish’s stomach protruding from its mouth. Bulging eyes and a bloated abdomen are other tell-tale signs.

To illustrate the harmful impacts of barotrauma, Fisheries researchers used conventional tackle and circle hooks to catch Golden snapper at various depths. The fish were brought to the surface, placed in a cage, returned to the same depth as they were caught and then filmed for 30 minutes.

The effects of barotrauma on the Golden snapper can be seen in the video.

The video footage confirms that Golden snapper caught in water deeper than 10 metres are unlikely to survive release, either due to the direct effects of barotrauma or because the compromised fish falls prey to reef predators such as sharks. Even if the fish manages to swim back to the bottom (and avoid predation), the internal injuries sustained are generally fatal over a short time period

The message is simple say DPIF researchers - Reef fish should not be targeted for catch and release if you are fishing at a depth greater than 10 metres.

The video can be viewed at http://www.nt.gov.au/d/Fisheries/barotrauma