WICKHAM and RUSSELL: EVALUATION OF MID-WATER ARTIFICIAL STRUCTURES 



The quantity offish attracted to the structures 

 during our study was not as large as the schools 

 reported by Klima and Wickham (1971). Coastal 

 pelagic school fish, however, were seasonally un- 

 available to the local fishery during the study 

 period and the fish captured around our struc- 

 tures were the only bait fish being landed. 



The rapid rate of recruitment during our study 

 was similar to the pattern of recruitment re- 

 ported by Klima and Wickham (1971) with fish 

 being observed at the structures the day follow- 

 ing placement. Our experimental results indi- 

 cated that the fish were recruited to the struc- 

 tures daily and no significant accumulation in 

 the fish population was observed when the struc- 

 tures were allowed to soak for 3 days. Conse- 

 quently, a greater total production was obtained 

 from the structures by making daily sets. Com- 

 parative day and night sets provided further 

 evidence that fish schools dispersed from struc- 

 tures at night during the new moon and new fish 

 were being recruited each day. 



We were unable to significantly improve the 

 rate or number of fish attracted to a structure 

 either by doubling its size in relation to our 

 standard structure, or by painting it with fluo- 

 rescent colors. The experimental changes in size 

 and color apparently did not extend the visible 

 range of a structure sufficiently to significantly 

 increase the number of fish attracted. Further 

 study is required to determine whether multiple 

 structure units might be successful as a means 

 for significantly improving the effective range 

 of structure attraction. 



The feasibility of harvesting structure-attrac- 

 ted coastal pelagic bait-fish schools with con- 

 ventional tom-weight purse seines was es- 

 tablished by the success of our quantitative 

 collection procedures. The incidence of success- 

 ful purse seine sets was greatly improved using 

 the artificial structure techniques since the 

 coastal pelagic fish schools remained in associa- 

 tion with the structures during the sets and 

 made no attempt to escape. 



Our experience during this study indicates 

 that artificial-structure fish attraction techniques 

 can be developed to facilitate the harvest of the 

 latent coastal pelagic resources in the Gulf of 

 Mexico. Artificial-structure fish attraction tech- 

 niques may also have sport fishing applications, 

 potential for development as a method for pro- 

 viding ground truth for fishery survey remote 

 sensor evaluation and as a method for monitor- 

 ing fish movements and relative changes in 

 abundance in certain geographical areas. These 

 potential applications for artificial-structure 

 fish attraction techniques will be the subject of 

 future investigations. 



ACKNOWLEDGMENTS 



We would like to thank John W. Watson, Jr. 

 for his contributions during all phases of the 

 field work, especially for his assistance as a diver. 

 Charles Roithmayr and Wayne Adkison provided 

 valuable assistance by obtaining purse-seine 

 catch samples and recording data aboard the 

 chartered purse seiner Gulf Ranger. 



LITERATURE CITED 



Gooding, R. M., and J. J. Magnuson. 



1967. Ecological significance of a drifting object to 

 pelagic fishes. Pac. Sci. 21:486-497. 

 Hunter. J. R.. and C. T. Mitchell. 



1967. Association of fishes with flotsam in the offshore 

 waters of Central America. U.S. Fish. Wild!. Serv.. 

 Fish. Bull. 66: 13-29. 



1968. Field experiments on the attraction of pelagic 

 fish to floating objects. J. Cons. 3 1 :427-434. 



Kjnney, J. S. 



1970. Visibility of colors underwater. Mar. Tech. Soc. 

 6th Annu. Conf. Expo. 1:627-636. 



Klima, E. F., and D. A. Wickham. 



1971. Attraction of coastal pelagic fishes with artificial 

 structures. Trans. Am. Fish. Soc. 100:86-99. 



Mitchell, C. T., and J. R. Hunter. 



1970. Fishes associated with drifting kelp, Macrocys- 

 tis pyrifera, off the coast of southern California and 

 northern Baja California. Calif. Fish Game. 

 56:288-297. 



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