Abstract:
Regulations and a strong conservation ethic among anglers make Striped Bass among the most frequently released coastal marine fishes. Given the currently assumed 9% release mortality rate, these recreational releases account for the majority of human removals from the stock. In an attempt to reduce this mortality rate, fishery managers have recently begun requiring that anglers use circle hooks when fishing with natural baits for Striped Bass. To measure the reduction in release mortality resulting from this rule change, we conducted a two-year acoustic telemetry experiment (n = 349 fish) to compare the survival of bass caught via circle hooks and conventional J-hooks. This telemetry dataset was also used to estimate mortality rate as a function of a release “condition score”, which is a simple visual assessment of the injury and vitality of released fish. By combining these telemetry results with fishery observations of release condition from a citizen science project (n = 8,349 fish), a machine learning model was developed to predict mortality rate from a suite of biological, environmental, and fishing variables. This model was then used to generate an updated comprehensive estimate of release mortality rate by accounting for fishery-wide patterns in the suite of predictors. Although we found that circle hooks did not provide a conservation benefit for Striped Bass, our results demonstrate that release mortality for the recreational fishery is on average 4%, which is less than half of the currently assumed rate. Furthermore, a significant positive relationship between mortality rate and fish size suggests that fishery removals are more focused on older fish than previously thought.
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https://umassd.zoom.us/j/93758230260
Meeting ID: 937 5823 0260
Passcode:426839
