AN EVALUATION OF MID-WATER ARTIFICIAL STRUCTURES 

 FOR ATTRACTING COASTAL PELAGIC FISHESi 



Donald A. Wickham and Gary M. Russell^ 



ABSTRACT 



Mid-water artificial structures positioned off Panama City, Fla. during August 1970 were 

 evaluated to determine their ability to attract coastal pelagic fishes. Quantitative and quali- 

 tative experimental results were obtained using scuba divers and purse seine catches. The 

 feasibility of using artificial structures to facilitate the commercial harvest of coastal pelagic 

 fishes with purse seines was established and the methods described. Average catch values of 

 398 kg (875 lb) per structure were obtained during a period when coastal pelagic fishes were 

 unavailable to the local fishery. A greater total production was obtained from structures 

 fished daily compared with those allowed to soak for 3 days before being fished. Experi- 

 mental purse seine collections established that fish leave the structures at night with new 

 recruitment occurring daily. No significant differences were obtained from preliminary exper- 

 iments to evaluate the effects of structure size and color on attraction effectiveness. A work- 

 ing hypothesis is presented to describe apparent behavioral mechanisms involved in the 

 attraction of some species of coastal pelagic schooling fish to objects in the sea. This study 

 indicates that artificial-structure fish-attraction has potential for development as a tech- 

 nique to facilitate the harvest of the latent coastal pelagic fishery resources in the Gulf of 

 Mexico. 



Artificial structures have been shown to be effec- 

 tive for attracting concentrations of pelagic 

 fishes (Hunter and Mitchell, 1968). Klima and 

 Wickham (1971) visually evaluated the species 

 and number of coastal pelagic fishes attracted 

 to experimental artificial structures in the north- 

 eastern Gulf of Mexico. These observations es- 

 tablished the feasibility of attracting large 

 numbers of coastal pelagic fishes with artificial 

 structures; however, many questions concern- 

 ing structure attraction characteristics and 

 dynamics as well as their actual usefulness in 

 augmenting conventional harvesting methods 

 for these species still remained unanswered. 



Studies were conducted during August 1970, 

 in 5 to 10 fathoms (9 to 18 m) of water offshore 

 of Shell Island, Panama City, Fla. to obtain 

 quantitative samples for evaluating the validity 

 of scuba-diver estimates of structure-attracted 

 fish aggi-egations, to evaluate methods for using 

 a conventional purse seine for capturing struc- 

 ture-attracted fish, and to obtain catch-produc- 

 tion values for single structures. We also evalu- 



' Contribution No. 234, Southeast Fisheries Center, 

 Pascagoula Laboratory, National Marine Fisheries Service. 



- Southeast Fisheries Center, National Marine Fisheries 

 Service, NOAA, Pascagoula, MS 39567. 



ated effects of structure soak time and size-color 

 differences on attraction effectiveness. Day and 

 night samples, plus scuba-diver observations of 

 fish behavior, provided additional clues to the 

 dynamics of the coastal pelagic fish aggregations 

 attracted to artificial structures. 



MATERIALS AND METHODS 



Our fish attraction devices were three-dimen- 

 sional structures. Each structure was construct- 

 ed from vinyl-cloth covered, wood and wire 

 frame panels. Two panels were fastened along 

 one side, permitting the structure to be stored 

 flat, but opened into a three-dimensional right 

 prism when deployed for fish attraction. Two 

 sizes of structures were used. The small struc- 

 ture panels were 0.9x1.5 m (3x5 ft) in size 

 and the large structures, with twice the surface 

 area of the smaller structures, were 1.8 X 1.5 m 

 (6X5 ft). All structures were white except 

 those painted for specific experiments. 



Structures were positioned 4-6 m (15-20 ft) 

 beneath the surface. The structure design and 

 mooring arrangement are illustrated in Figure 1. 

 Structures were spaced at approximately 0.8-km 



Manuscript accepted May 1973. 



FISHERY BULLETIN: VOL. 72. NO. 1. 1974. 



181 



