Post-release Mortality and Behavior of Sharks in Shore-Based Recreational Fisheries of Texas Using Citizen Scientists and Low-cost Tags

The goal of this project is to develop a cooperative research initiative to understand post-release behavior and mortality of sharks commonly captured in shore-based recreational fisheries. Current post-release mortality rate estimates used in stock assessment models are derived from boat-based shark fisheries, which differ from shore-based fisheries that expose sharks to shallow, warm water where air exposure may be prolonged.

The Texas coast encompasses one of the largest shore-based fisheries for sharks in the U.S., and Project Investigators Dr. Greg Stunz and Dr. Matthew Streich have established robust cooperative relationships with shore-based recreational shark anglers. This represents a model system to generate discard mortality estimates. To date, over 5,000 conventional tags have been deployed on shore-caught sharks through cooperative relationships between anglers and scientists.

These passive tagging efforts have provided information on post-release survival and movements, but low recapture rates limit robust statistical analysis of mortality and detailed examination of post-release behavior. Advances in electronic tagging technology, including acceleration data loggers (ADLs) and pop-up satellite archival transmitting tags (PSATs), now provide unprecedented insight into fine-scale (e.g. seconds to minutes with ADLs) and long-term (e.g. daily to monthly with PSAT) behavior of sharks post-release.

This project will cooperatively engage recreational shore-based shark anglers to deploy ADLs and PSATs on blacktip, bull, tiger, and scalloped hammerheads to estimate post-release behavior and mortality rates. These species vary in physiological sensitivity to capture from highly sensitive (hammerhead) to less sensitive (tiger) and ensures increased tag deployment rates in unpredictable but diverse catches.

Research objectives include:

1. Characterize both fine and broad-scale post-release behavior and mortality of beach-caught sharks in Texas using ADLs and PSATs deployed by experienced recreational anglers;
2. Compare behavioral capture responses among diverse shark species with variable capture-sensitivities and seasonal environmental variables;
3. Host both pre- and post- tagging shark angler workshops to train anglers in shark identification, disseminate tagging results, and discuss how results can be applied to shark conservation efforts.

This project runs September 2019 through August 2021.