A Life History Review for Red Snapper in the Gulf of Mexico with an Evaluation of the Importance of Offshore Petroleum Platforms and Other Artificial Reefs

Abstract

Red snapper mature as early as age 2, have high fecundity (a 10-year-old female produces 60 million eggs per year), and may live for over 50 years. Eggs, larvae, and post-settlement juveniles typically show high rates of natural mortality. For example, of the 60 million eggs produced annually by a 10-year-old female, only about 450 would survive to 5 cm, the size at which they enter the shrimp fishery. Changes in abundance by size and age appear to be consistent with density dependence in survival rate from ages 0 to 1 and likely ages 0 to 2. Red snapper are attracted to structure or reef habitat at all ages, but larger, older fish also occur over open habitat once they have reached a size that renders them largely invulnerable to predation. Artificial reefs comprise a small fraction of the overall high-relief reef habitat, but harbor a large fraction of the present-day age 2 red snapper populations. Prior to the proliferation of artificial reefs in the northern Gulf, age 2 red snapper may have historically occurred mainly over open-bottom, sand-mud benthic habitat where natural and shrimp trawl bycatch mortality was high. Age 2 fish dominate red snapper populations at artificial reefs, whereas the age composition of red snapper at natural reefs usually show older ages are dominant. The present day red snapper fishery is heavily dependent on catches at artificial reefs. Evidence is presented that suggests red snapper production in the northern Gulf likely has been increased by the establishment of significant numbers of artificial reefs.

Keywords:

• red snapper
• Lutjanus campechanus
• oil and gas platforms
• density-dependent mortality
• life history
• artificial reefs

ACKNOWLEDGEMENTS

This article was enabled by funding from the Minerals Management Service (Contract 1435–01–05–39082) to VERSAR, Inc. This project provided for a literature search and data synthesis of biological information for use in management decisions concerning decommissioning of offshore oil and gas structures in the Gulf of Mexico. We especially thank Ed Weber and Jon Vølstad of VERSAR, Inc., for their support on this project. This is a contribution of the Department of Fisheries and Allied Aquacultures, Auburn University, and the Alabama Agricultural Experiment Station.

Notes

*Pre-recruit.

**Recruit.

***M_egg values of 13.3 in Gallaway et al. (2007) revised to 11.8 and larval- and juvenile 1-stage durations changed from the Gallaway et al. (2001) estimates of 27 and 39 days to 28 and 38 days, respectively. These changes reflect new data utilized in the methodology described in Gallaway et al. (2007).