Comparison and cost-benefit analysis of PIT tag antennae resighting and seine-net recapture techniques for survival analysis of an estuarine-dependent fish

Studies of fish ecology are enhanced by precise and accurate knowledge of survival, which can be estimated from capture-recapture/resighting based survival probabilities. We conducted a cost-benefit analysis of resighting by an array of 11 autonomous PIT tag antennae and recapture by seine netting, and compared the effectiveness of the two methods for recapturing/resighting marked fish in an estuarine environment. During three separate marking periods, we marked a total of 2109 fish with PIT tags, recapturing 106 by seine (5.0%) and resighting 1700 by antennae (80.6%). Antennae resulted in precise monthly survival estimates while seine netting did not, but antennae did not collect ancillary data (e.g., growth) and their use was limited to areas where fish used constricted passes <10–30 m in width. Despite a reliance on seine nets to capture fish for marking and high initial construction costs, the cost-effectiveness of PIT tag antennae (US$45–$57 per unique fish resighted) exceeded that of seine netting (US$167–$934). Considering physical capture was required to mark fish, the use of PIT tag antennae is a dual-method approach incorporating both physical captures and telemetry. This dual-method approach can collect cost-effective and highly detailed data that could enhance our ability to make informed management and conservation decisions.