Abstract

The Sustainable Fisheries Act of 1996 called for the identification and evaluation of essential fish habitat. However, the ability to make accurate estimates of fish abundance over a particular habitat is contingent upon the use of appropriate sampling methods. The objectives of this study were to compare the catch per unit area (A), the relative catchability (q-ratio), and the length-specific bias of four different gear types on sampling red snapper (Lutjanus campechanus) over natural low-relief reef habitats on the inner continental shelf of the northern Gulf of Mexico. Specifically, our goal was to assess the overall performance of using a standard otter trawl, a crab trap, a chevron trap, and a stationary 4-camera underwater video array during six quarterly sampling cruises performed in 2004 and 2005. Results indicate that trawls collected the most red snapper per unit area and had catchability estimates for juvenile red snapper that were three to five times greater than the crab traps. Additionally, trawls were the most selective gear for collecting juvenile and sub-adult red snapper from 30 to 250 mm total length (TL) (ages 0 and 1). The chevron trap collected the second highest number of red snapper and proved most useful at collecting red snapper from 150 to 440 mm TL (ages 1-5). The catchability of the chevron trap was three times greater than the underwater video array, which was size selective for both 100 to 150 mm TL (age 0) and 300 to 350 mm TL (ages 2-3) red snapper. The ultimate goal of the project was to provide the most appropriate survey methods for future studies that aim to collect red snapper over natural low-relief reef habitats. Our comparison has demonstrated that the chevron trap is most effective for sampling adults, while trawls appeared to be the most effective gear for sampling age 0 fish

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