Abstract

Red Snapper (Lutjanus campechanus) is one of the most targeted species in the northern Gulf of Mexico recreational fishery; however, their reproduction is not fully understood. Previous reproductive studies have focused on differences between structures with limited inclusion of depth. We compared several reproductive parameters of female Red Snapper across three depth strata from a 5-year study. A total of 1,026 females (168-795 mm FL) were captured on artificial structures via vertical longline sampling from three depth strata (shallow: <20 m, mid: 20-49 m, and deep: 50-100 m) off the Mississippi coast during March-November 2016-2020. Gonadal tissue was excised from each fish, weighed, and preserved for histological processing and fecundity analysis. No significant differences between depth strata were present for either the percentage of oocytes in oocyte maturation or GSI. There was a significant relationship between the occurrence of reproductively active females (RA, spawning capable and actively spawning phases) and depth (X22=32.06, p<0.001), and the percentage of RA females increased from 29% to 56% from shallow to deep water. Batch fecundity and relative batch fecundity were highest in deep depths but there were no significant differences among depth strata. Spawning interval (number of days between spawning) calculated using the post- ovulatory follicle method was significantly shorter at deep depths (2.12 days) compared to mid (4.53 days) and shallow (4.06 days) depths (X22=22.619, p=0.001). Our results suggest that female Red Snapper have a greater reproductive potential in deep water and this information will be important for future stock assessments and management decisions.

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