Descender Devices are Promising Tools for Increasing Survival in Deepwater Groupers. Runde, B., J. & Buckel, J., A. Marine and Coastal Fisheries, 10(2):100-117, John Wiley and Sons Inc., 4, 2018.
Descender Devices are Promising Tools for Increasing Survival in Deepwater Groupers [pdf]Paper  abstract   bibtex   
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 dis- card 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.

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