The role of oil and gas platforms in providing habitat for northern Gulf of Mexico red snapper Lutjanus campechanus
Abstract
“A fishery independent sampling of fishes at Ship Shoal 209 (SS 209) based on collection of moribund fish resulting from the explosive removal of an obsolete gas rig revealed a proportionally large population of red snapper. Fully 37% (n=373) of the fish mortalities recovered subsequent to the explosive detonation were red snapper. Analysis of the fishery independent data gathered from the SS 209 detonation must be tempered with the recognition that it is indeed a chronological “snapshot” of the red snapper population (Nieland and Wilson, in press). In a hydroacoustic study of the fish population around a much larger (45 m X 20 m; 19,800 m3 volume), but nearby, platform, Stanley (1994) reported the red snapper population varying from 1,200 to 8,200 individuals.
Quantitative estimates of the inhabitation of platforms by red snapper can be derived from both the efforts of the National Marine Fisheries Service which has conducted periodic assessment of the effects of explosive platform removal on the associated fish populations at select sites in the GOM and the acoustic surveys done by personnel from Louisiana State University. Gitschlag et al. (2001) collected moribund fishes following explosive detonations at nine sites off Louisiana and Texas (14-36 m water depth) and found an average of 19% (n=500) were red snapper (Figure 2B.11). Stanley and Wilson (various) have reported on the fish communities of ten sites (22-110 m depth) to which a total of 38 trips were made and found an average of 21% (n= 2100) were red snapper.
MMS reports that there are approximately 2,500 platforms in the northern Gulf of Mexico water at depths ranging from 20 m to 100 m . Based on the estimated numbers of red snapper given above, from 1.2 to 7.2 million red snapper live around platforms placed in this depth range. Many of these may be relatively young individuals given that Nieland and Wilson (in press) reported that the red snapper around the SS209 platform were predominantly 2-4 years old. These estimates are based on a limited number of surveys, but they suggest a range of red snapper abundances that reflect the ubiquitous presence of red snapper at oil and gas platforms. We should continue this line of investigation to determine if platforms have become “essential’ to the persistence of a large population of red snapper in the northern GOM.”