Abstract

Offshore oil and gas platforms provide habitat for many marine fish species in the northern Gulf of Mexico. By law, the owning company is required to remove obsolete platforms. The most economical method is explosive removal, but such removals usually result in high mortalities of economically important red snapper (Lutjanus campechanus) and habitat loss. The present study used telemetry methods to examine the movement patterns and residency of red snapper (n=54) around three platforms in the northern Gulf of Mexico from March 2017 to May 2018 to estimate site fidelity, residency and area use. Site fidelity = 30% y-1 and residency = 11 months. Area use or home range (95 % kernel density estimates) was positively correlated to temperature and negatively correlated to dissolved oxygen (DO). Salinity showed little change and was well within the tolerance range for Lutjanidae. Monthly area use increased in the summer and fall (F11, 249 = 11.46, P < 0.001). Diel patterns of area use differed significantly (F71, 4207 = 3.55, P < 0.001). Over all sites area use was significantly smaller at dawn (0500-0700), but similar during day and night hours. Many red snapper (n = 18) in the present study displayed homing behavior with frequent short-term forays away from their home reef from August to November (88% < 4 days). Red snapper showed a high affinity for platform structure with most (76%) positions within or near platform structure (mean distance = 20 m). The present study showed long term, high site fidelity to platforms in the northern Gulf of Mexico, suggesting that offshore platforms provide important habitat for red snapper and required removals may cause unexpected declines in this species.

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