Spatial dynamics of sea turtle abundance and shrimping intensity in the USGulf of Mexico

In order to examine the scientific feasibility of area closures for sea tur tle protection, we determined the spatial dynamics of sea turtles for the U .S. Gulf of Mexico by analyzing National Marine Fisheries Service (NMFS) ae rial survey data in September, October, and November of 1992, 1993, and 199 4. Turtle sightings were grouped into depth zones and NMFS fishery statisti cal zones, and strip transect methods were used to estimate the relative ab undance of sea turtles in each Average shrimping intensity was calculated f or each subzone for all months of 1992, 1993, and 1994, as well as for the months and locations of the aerial survey. The spatial overlap of sea turtl e abundance and shrimping intensity suggested regions where interactions ar e likely to occur. Sea turtles were observed at much higher rates along the coast of Florida than in the Western Gulf; the highest density of sea turt les was observed in the Florida Keys region (0.525 turtles/km(2)). Shrimpin g intensity was highest in the Western Gulf along the coast of Texas and Lo uisiana, for both annual and fall estimates.,Among alternative management s cenarios, area closures in conjunction with continued Turtle Excluder Devic e (TED) requirements would probably best prevent sea turtles from future ex tinction. By implementing shrimping closures off of South Padre Island, Tex as, a potential second nesting population of Kemp's ridleys (Lepidochelys k empi) could he protected. Closing where shrimping intensity is low and sea turtle abundance is high (e.g., South Florida waters) would protect sea tur tles without economically impacting a large number of shrimpers.