Stanley and Wilson Fish populations around oil and gas structures off Louisiana 



721 



Offshore Lease Areas 



1 West Cameron 7 South Timbalier 



2 East Cameron 8 South Peho 



3 Vermilion 9 Grand Isle 



4 South Marsh Island 10 West Delta 



5 Eugene Island 1 1 South Pass 



6 Ship Shoal 12 Main Pass 



13 Breton Sound 



Figure 2 



Three regions of the Louisiana offshore study area. 



outlined by Demory and Golden (1983). Information 

 entered into the logbooks included date, numlier of 

 anglers, identity of the oil and gas platform fished, 

 fishing time (not including travel time), fishing method, 

 bait used, and the number of fish caught by species. 

 Participants were asked to complete at least one page 

 of the logbook for each fishing day (Fig. 1). Logbook 

 data were collected from March 1987 to December 

 1988. Due to the difficulty of identifying certain species 

 of fish such as snapper other than red snapper, 

 groupers, sharks, and silver and sand seatrout, these 

 species were classified as other snapper, groupers, 

 sharks, and silver/sand seatrout, respectively. Other 

 data acquired from study participants included boat 

 length (m), total engine horsepower, and the presence 

 of electronic gear (i.e., LORAN, graph recorders, and 

 echosounders) which aided in the capture of fish. Sub- 

 merged surface area (m-) and volume of water en- 

 closed (m'') by each structure utilized by the partici- 

 pants in 1987 were calculated from schematic diagi-ams 

 provided by the platform operators. 



Fishing effort and CPUE (number of fish caught/ 

 angler hour) estimates were separated into two cate- 

 gories: nearshore and offshore fishing. Nearshore 

 fishing ai'ciund oil and gas platforms was defined as any 

 time at which spotted seatrout were caught, and off- 

 shore fishing was defined as trips during which spotted 

 seatrout were not caught. Offshore fishing was fui'ther 

 subdivided into bottom fishing (during which time the 

 boat is moored to an oil and gas platform) and troll- 

 ing. The rationale for the separation of the effort into 

 two categories was due to the segregation of the fish 

 species, as spotted seatrout and red snapper were 

 caught together only 0.7% of the time. Nearshore 

 fishing generally took place in less than 10 m of water 

 where target species were nearshore species such as 

 spotted seatrout, red drum, Spanish mackerel, etc. In 

 contrast, offshore fishing occurred in much deeper 

 water'and the target species was usually red snapper; 

 however, a wide range of species were caught with the 

 exception of spotted seatrout. The bait and gear used 

 during the two types of fishing were very different. 



