My Master’s research at California State University, Long Beach, under the direction of Dr. Chris Lowe, was focused on the effects of angling-induced barotrauma on rockfish survival. Barotrauma is another word for pressure-related injuries. The swim bladder that rockfishes use for buoyancy control is closed, so it can overinflate when a fish is rapidly reeled to the surface. It’s similar to what happens to SCUBA divers that ascend to the surface too quickly…the gases in their blood and tissues can expand, causing embolism and even death. In fish, sometimes swim bladder expansion is so severe that it ruptures, causing damage to internal organs and forcing the stomach or esophagus to protrude from the mouth. Externally, the signs of barotrauma can be gruesome - gas bubbles on the skin and eyes, bulging eyes, a prolapsed cloaca. On top of all of that, the overinflated swimbladder prevents the fish from swimming back down to depth. It was thought that a fish with signs of barotrauma was most likely a goner, even if it was strong enough to overcome its positive buoyancy to swim back to the depths.

Our research helped to demonstrate that rockfish survival and signs of barotrauma is species-specific and that the severity of barotrauma is not a useful predictor of survival. Rather, time is of the essence, no matter the species or how badly the fish looks. With the use of descending devices (i.e., simple devices available to anglers to recompress fish), many rockfishes suffering barotrauma can show high survival if released back to depth quickly. Importantly, as a result of this research and a wealth of subsequent studies, fishery managers in California now have a better understanding of rockfish discard mortality.

Check out more about our research and barotrauma-related information below:

An informative brochure I collaborated on with Christina Johnson of California Sea Grant” Bring That Rockfish Down!

An article co-written by myself and Chris Lowe for The Slate, an American Academy of Underwater Sciences news publication…read about our cool study design and implications of our results for management Bloating

Our publication Jarvis & Lowe 2008

Great one-stop shop for all things rockfish barotrauma CDFW Page