Barotrauma in Lake Erie Yellow Perch and Implications to Management

Barotrauma is caused by the change in ambient pressure when a fish is brought up from deeper water.  This occurrence can bias diet studies and is commonly seen and in Lake Erie’s yellow perch fisheries.  Our main objective was to determine the depths where barotrauma occurs.  We also investigated the effects of size, sex, month, and their interactions associated with barotrauma. Total length, gender, and stomach eversion of yellow perch were recorded over three years of trawl surveys. We found depth, which explained 92% of the variability, and size to be significant factors that affected the rate of barotrauma.  There was a significant difference in the rate of barotrauma in yellow perch less than and greater than 110mm.  The rate of barotrauma increased nonlinearly with depth which we developed into a barotrauma/depth model.  Our model was then applied to the 2013 commercial and sport fisheries to examine impacts of mortality from bycatch (fish thrown back). We assumed mortality from barotrauma to be 100% and the bycatch mortality represented a very small percentage of the population.  To fully understand the real impact on the population, it is critical that managers attain accurate estimates of yellow perch bycatch.