Abstract

The banks off the Louisiana-Texas shelf in the northwestern Gulf of Mexico provide a diverse collection of habitat zones each with characteristic fish assemblages. These habitat-assemblage relationships have been shown to be consistent across several banks, but related to additional factors such as depth, bank size, and substrate complexity. Understanding the habitat drivers and associations of the many recreationally and commercially important fish species that inhabit these banks is critical to management. Video data were recorded at six shelf-edge bank sites (Rankin, Bright, McGrail, Sidner, Alderdice, and Jakkula) at varying depth and habitat type using a baited remote underwater video (BRUV) array consisting of two stereo pairs of cameras. Twenty minutes of each video was reviewed in EventMeasure software to identify fish to the lowest possible taxonomic level and measure abundance (calculated as MaxN, the maximum number of a given species in any single frame) as well as record habitat variables. Relationships between fish species assemblages, habitat zones, and other habitat characteristics were explored using traditional metrics of diversity, evenness, and richness as well as permutational multivariate analysis of variance (PERMANOVA), non-metric multidimensional scaling (NMDS), and principle component analysis (PCA) in R. With five of the six sites included in the preferred alternative for expansion of the Flower Garden Banks National Marine Sanctuary, understanding which species utilize habitats on these banks and what factors drive assemblages will directly inform the likely utility of sanctuary expansion and/or the habitats most in need of additional protection. Species, such as those of grouper and snapper, are of particular interest due to their economic importance and management status.

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