Reproduction and Diet of Red Snapper Lutjanus campechanus on Natural and Artificial Reefs in the Northwestern Gulf of Mexico
Downey, Charles H.
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Energy exploration in the Gulf of Mexico (Gulf) has resulted in the addition of numerous oil and gas production platforms adding structurally complex habitat to an area otherwise comprised of primarily barren mud/sand bottom. The impact of these artificial structures on fish populations is generally unknown, and there is ongoing debate regarding their performance in comparison to natural reefs. Thus, the purpose of this study was to characterize trends in Red Snapper reproduction and diet in the northwestern Gulf at oil and gas platforms relative to natural reefs. Red Snapper were collected from standing and reefed platforms and natural hard-bottom. Fecundity parameters (sex, total weight, gonad weight, total length) were measured, and these data showed Red Snapper fecundity and spawning behavior were similar among natural, standing, and reefed habitats. These results suggest that artificial reefs are functionally similar to natural reefs in terms of reproductive output. I also examined the composition of prey items present in the stomachs of Red Snapper at each of these areas. I found that prey composition among habitats was similar, and there was a temporal influence on the composition of fish diets. In addition, I created feeding strategy diagrams for each habitat type which showed that Red Snapper exhibit similar strategies of prey selection at all habitats. Therefore, artificial reefs appear to be providing a similar means of prey selection as natural banks for Red Snapper in the northwestern Gulf. Furthermore, based on comparative studies, apparent differences exist in the Gulf indicating there may be regional differences in these life history characteristics that could influence the management of this species. Future studies should consider site specific characteristics to further clarify the question of habitat influence on reproduction and diet which would improve reefing strategies in the northwestern Gulf of Mexico. Collectively, this study suggests that artificial reefs are a valid tool for creating additional habitat for Red Snapper in the northwestern Gulf in terms of feeding and reproduction.
A thesis Submitted in Partial Fulfillment of the Requirements for the Degree of MASTER OF SCIENCE in MARINE BIOLOGY from Texas A&M University-Corpus Christi in Corpus Christi, Texas.