Descender Devices are Promising Tools for Increasing Survival in Deepwater Groupers Marine and Coastal Fisheries: Dynamics, Management, and Ecosystem Science

Discard survival of deepwater (>60 m) groupers (Serranidae; Epinephelinae) is often assumed to be 0% given the severity of barotrauma and the inability of fish to submerge. We used acoustic telemetry to study the activity of 19 deepwater grouper after a recompressed release with a descender device, achieved by rapidly returning fish to a depth where expanded gases can contract. The species tested were the Scamp Mycteroperca phenax (n = 8), Snowy Grouper Hyporthodus niveatus (n = 7), and Speckled Hind Epinephelus drummondhayi (n = 4). Individuals of all three species showed post‐recompression variation in water depth and acceleration indicative of survival, whereas information from other tags indicated discard mortality. Nonparametric Kaplan–Meier survivorship procedures yielded a 14‐d survival estimate of 0.50 (95% confidence interval = 0.10–0.91); although low, this estimate is higher than the currently assumed 0% survival. Additionally, our estimate of discard survival is likely biased low because we assumed that no individuals shed their tag, which is unlikely for our attachment method. A technique to increase discard survival of deepwater groupers may lead to better‐constructed regulations for reef fishes in the southeastern USA and in other areas where these species are caught and released. 2018 Grant no. NA14NMF4540061 NMFS (National Marine Fisheries Service) SER (Southeast Region) Submitted https://doi.org/10.1002/mcf2.10010 CC BY 1951