Seasonal and spatial variation in the abundance and size distribution of fishes associated with a petroleum platform in the northern Gulf of Mexico

Abstract

Stationary dual-beam hydroacoustics and visual point count surveys were used in tandem to measure the density, target strength, and species composition of fishes associated with a petroleum platform in the northern Gulf of Mexico. Fish densities ranged from 0 to 10.5 fish · m-3 during monthly sampling trips from January 1991 to May 1992. Density and target strength were spatially and temporally variable. Target strengths varied significantly with side of the platform, month, and east and north current vectors. Density varied significantly with platform side, month, east current vector, and depth. Density and target strength did not change over 24 h periods or with water temperature. Fish densities were highest adjacent to the platform and decreased significantly beyond 16 m. Approximately 1990 - 28<|>100 fish were associated with the platform depending on the month. A total of 19 species were observed at the platform, with Chaetodipterus faber, Caranx fusus, Seriola dumerili, Balistes capriscus,Lutjanus campechanus, andArchosargus probatocephalus constituting 97% of observed fishes. Based on our results, we conclude that the fishes associated with a petroleum platform conform with the open nonequilibrium hypothesis proposed for fishes in coral reef habitats.

Red snapper management in the Gulf of Mexico: science- or faith-based?

“…We argue that the amount of habitat for an adult bet-hedger like red snapper, especially artificial habitats that account for \5% (Stanley and Wilson 2003) of total useable habitat as compared to suitable natural habitats, probably does not limit recruitment or population size. The useable habitat increase due to artificial habitats is likely less even than the 5% reported above because this estimate includes all oil and gas platforms, many of which are not suitable habitat for red snapper, especially the inshore to midshelf platforms in the northwestern Gulf that are subjected to Mississippi River discharge.…”

Use of Oil and Gas Platforms as Habitat in Louisiana's Artificial Reef Program

“…This habitat is particularly important in the northern Gulf of Mexico, where bottoms are typically clay, silt, or sand, with little or no relief. The addition of these platforms and other oil-and-gas-related facilities has undoubtedly affected fish populations, although such effects are not well understood (Stanley, 1994). Since installation, these platforms have been an important component of both the recreational and commercial fishing industries and have long been recognized as de facto artificial reefs.…”

“…(1989) found that fish densities were 5 to 50 times higher immediately adjacent to a platform than at distances 50 m away. The dominant species in water depths between 3 and 18.3 m included red snapper (Lutjanus campechanus), bluefish (Pomatmnus saltatrix), Atlantic spadefish ( Chaetodipterus fabm), blue runner ( Camnx crysos), gray triggerfish (Balistes capriscus), grunts (Haemulidae), greater amberjack (Seriola dumerili), sheepshead (Archosargus probatocephalus), and groupers (Serranidae) (Gallaway, 1980;Gallaway and Lewbel, 1982;Putt, 1982;Stanley and Wilson, 1990;Continental Shelf Associates, unpubl.). Putt (1982) found thatJune-Sep. fish populations varied in abundance near reefs by a factor of 2, while species composition remained constant.…”

“…Putt (1982) found thatJune-Sep. fish populations varied in abundance near reefs by a factor of 2, while species composition remained constant. Stanley andWilson (1990, 1991) examined catch records from recreational and charter boat anglers in the northern Gulf and found that catch rates and species composition varied with season, platform size, and water depth. Stanley (1994) estimated the sphere of influence around a platform in 22m of water to be about 16m in radius from the jacket.…”

“…In a study conducted from Sep. 1990 to June 1992, Stanley estimated the monthly average number of fish in the sphere of influence to be approximately 12,000, with fishes ranging in size from 2.4 em to 1.1 m. Fish densities varied not only seasonally, but also spatially, with the highest densities occurring on the north and east sides of the platform and the lowest densities occurring on the south and west sides (Stanley 1994).…”