Red snapper (Lutjanus campechanus) abundance on oil and gas platforms based on mark–recapture methods in the northern Gulf of Mexico

Abstract

Oil and gas platforms provide reef habitat for many fish species on continental shelves. Red snapper ( Lutjanus campechanus) are an important component of these communities in the Gulf of Mexico, but abundance estimates are difficult to obtain. Hydroacoustic and visual-video surveys have been applied in previous abundance estimates, but such methods have difficulties. To improve abundance and fishing mortality ( F) estimates, mark–recapture methods were applied to red snapper at 22 platforms in the northern Gulf of Mexico from February 2017 through May 2020. Estimates were adjusted for emigration, tagging mortality, natural mortality, fisher nonreporting, and tag retention. Mean ± SE abundance·platform–1 (563 ± 107, range = 109–1407) and F (0.36, range = 0–1.25·platform–1) were not significantly affected by year, location, depth, or distance-from-shore. Based on an estimated 904 platforms, there were 508 952 (900 845 kg) red snapper on platforms. This indicated that red snapper on platforms accounted for only 1.2% of the 2016 Gulf of Mexico red snapper biomass. Thus, required removal of platforms will not significantly affect the red snapper stock in this area.