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



729 



knowledgeable fishermen who were as skilled as the 

 professional charterboat operators. 



The CPUE of the study participants was probably 

 much higher than that for average offshore saltwater 

 fishermen in Louisiana. Since charterboat operators 

 are professional fishermen who make their living by 

 catching fish, and the private vessel anglers partici- 

 pating in the program were equally as skilled, the catch 

 rates by these groups do not reflect average catches. 

 Both groups have a higher success rate than do casual 

 fishermen who rarely catch fish due to improper tech- 

 niques and do not target their effort (Casselman et al. 

 1985). Consequently, the CPUE's presented are not 

 applicable to all fishermen, only to skilled, dedicated, 

 amateur anglers and charterboat operators. 



Spotted seatrout and red snapper were the target 

 species of private vessel anglers and charterboat 

 operators, as indicated by their domination of respec- 

 tive CPUE estimates for nearshore and offshore bot- 

 tom fishing and based on past research from a salt- 

 water recreational angling survey (Stanley and Wilson 

 1989). Casselman et al. (1985) reported that the CPUE 

 of avid recreational fishermen can be used as an index 

 of relative abundance, and if data are collected over 

 a long period of time, changes in CPUE can reflect fluc- 

 tuations in the populations of the target species. Off- 

 shore trolling CPUE was not dominated by a single 

 species, indicating that fishermen were not targeting 

 their effort for any particular species; therefore, CPUE 

 estimates while trolling would not reflect changes in 

 abundance to the same extent as nearshore and off- 

 shore bottom-fishing CPUE estimates. 



Conclusions 



The catch rates of private vessel anglers and charter- 

 boat operators around oil and gas platforms in the 

 northern Gulf of Mexico were high, with their effort 

 targeted towards red snapper while offshore bottom 

 fishing, and spotted seatrout while nearshore fishing. 

 Catch rates while trolling were more uniform and not 

 dominated by any one species. Catch rates between the 

 user groups and across the regions were similar, al- 

 though some minor differences were detected. 



Based on comparisons of catch rates and composi- 

 tion between our results and past studies, a shift in the 

 abundance of certain species has occurred near oil and 

 gas platforms off the Louisiana coast. Studies from 

 1978 to 1985 found Atlantic croaker and silver/sand 

 seatrout constituted the largest portion of the catch and 

 had the highest catch rates, while we found that red 

 snapper dominated the catch statistics while offshore 

 bottom fishing. Little change in the patterns of species 

 abundance appears to have occurred for species tar- 



geted while offshore trolling and nearshore fishing 

 around oil and gas platforms, based on comparisons 

 with earlier studies. 



The physical construction of oil and gas platforms 

 precludes the sampling of the associated sportfish 

 populations using traditional methods (e.g., gillnets, 

 trawls). The success of this logbook program indicates 

 that the collection of CPLIE data over long periods of 

 time may be an effective technique of monitoring fish 

 populations associated with the platforms. Although 

 the data supplied by the logbooks is an index of relative 

 abundance of fish susceptible to angling and is biased 

 towards larger individuals, it provides a valuable source 

 of data which is otherwise difficult to obtain. 



Acknowledgments 



The authors thank the 55 anglers and 10 charterboat 

 operators for maintaining logbooks over the study 

 period. Dr. James Geaghan for statistical counseling, 

 and Dr. Linda Jones and two anonymous reviewers for 

 improving the quality of the manuscript. 



Citations 



Brusher, H.A.. and B.J. Palko 



1985 Charter boat catch and effort from southeastern U.S. 

 waters, 1983. Mar, Fish, Rev. 47(3):.54-6fi. 

 1987 Results from the 1984 and 1985 charter boat surveys in 

 southeastern U.S. waters and the U,S, Caribbean Sea. Mar. 

 Fish, Rev. 49(2):109-117, 

 Brusher, H.A.. M.L. Williams, L. Trent, and B.J. Palko 



1984 Using charter boat catch records for fisheries manage- 

 ment. Mar, Fish, Rev. 46(3):48-.56, 



Casselman, J.M., M.A. Henderson, and T. Schaner 



1985 Fish sampling techniques — natural and observational 

 variability. Contril). No, 85-00, Ontario Minist. Nat, Resourc. 

 Fish. Branch, Res. Sect,, Maple, Ontario. Canada. 52 p, 



Coleman, E. 



1984 Coastal Louisiana: Climate and recreation, Louisiana 

 State Univ. Sea Grant Prog.. Baton Rouge, 24 p. 

 Continental Shelf Associates, Inc. 



1982 Study of the effect of oil and gas activities on reef fish 

 populations in the Gulf of Me.xico OCS area. OCS Rep. 

 MMS82-010. U.S, Dep, Int., Minerals Manage. Serv.. Gulf of 

 Me.xico OCS Region. New Orleans. 210 p. 



Demory, R.L.. and J.T. Golden 



1983 Sampling the commercial catch. In Nielson, L.A.. and 

 D,L, Johnson, (eds.), Fisheries techniques, p, 421-430, Am. 

 Fish. Soc. Bethesda. MD. 



Ditton, R.B., and J. Auyong 



1984 Fishing offshore platforms central Gulf of Mexico: An 

 analysis of recreational and commercial fishing use at 164 major 

 offshore petroleum structures. OCS Mon<igr, 84-0006. U.S, 

 Dep. Int.. Minerals Manage, Serv,. Gulf of Mexico OCS Region, 

 Metarie, LA. 158 p. 



