Volume 70

Mortality Estimates for Red Snapper, Lutjanus campechanus, Based on Acoustic Telemetry and Conventional Tagging in the Northern Gulf of Mexico

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Date: November, 2017

Pages: 163-164

Event: Proceedings of the Seventy Annual Gulf and Caribbean Fisheries Institute

City: Merida, Yucatan

Country: México


We used the VEMCO VPS to estimate mortalities and fine-scale movements (~1 m) of red snapper, Lutjanus campechanus, on artificial reef sites (n = 4) in the northern Gulf of Mexico from 2015 to 2017. Additional receivers (n = 22) on surrounding sites confirmed emigrations of tagged red snapper from the tagging sites. We applied a 6-d tagging recovery period before fish were included in the analyses. In 2015 there were 50 transmitter tagged red snapper available for recapture: four emigrated after tracking for 213 to 963 d, 20 were caught (F = 1.1) and M = 0.04. In 2016 there were 38 red snapper available for recapture: six fish emigrated after tracking for 337 to 1380 d, 14 were caught (F = 0.52) and M = 0.03. Among the 2015 recaptures, 18 (90 %) were reported and two (10 %) were not reported, but identified as caught from telemetry data. Among the 2016 recaptured red snapper 86 % (n = 12) were reported and 14 % (n = 2) were not reported. We also released 846 external tagged red snapper from 2015 to 2017 on 84 artificial reefs at close to 10 tagged fish per reef and offered a $150 reward for recaptured fish. Based on conventional tagging and applying 10 % non-reporting rate from telemetry F = 0.36 in 2015. In 2016, fishing mortality decreased to F = 0.25 after applying a 14 % non-reporting rate. In 2017 preliminary estimates showed F = 0.18 after applying a 32 % non-reporting rate from 2017 telemetry data, but more tag returns are expected as fishing was still occurring. Telemetry based estimates were higher than conventional tag estimates and may have overestimated fishing mortality, but provided important information on non-reporting rates. The combined telemetry and conventional tagging provided the best approach for estimating fishing mortality for red snapper on the continental shelf in the northern Gulf of Mexico.

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