BULLETIN OF MARINE SCIENCE, 44(2): 960-972, 1989

ASSOCIATION OF FISHES WITH FISH AGGREGATION

DEVICES: EFFECTS OF STRUCTURE SIZE ON

FISH ABUNDANCE

Rodney A. Rountree

ABSTRACT

The hypothesis that the abundance of fishes associated with fish aggregation devices (FADS) is a function of the degree of shelter provided by the structure was tested by comparing recruitment to three sizes of mid-water FADS. Each treatment was replicated six times and the eighteen FADS were deployed in a randomized block array in 14 m of water in the Atlantic Ocean off South Carolina. A total of thirteen species of fishes was observed to associate with the FADS. Eighty-nine FADS were censused in eight surveys from May through November 1985. The fauna associated with the FADs was very similar to published reports of fauna associated with Sargassum spp. and jellyfish, suggesting similar origins and causes of these associations. Decapterus punctatus was the most frequently occurring (70) and abundant species (mean = 576 fish/FAD). The total number of fishes and number of D. punctatus per FAD exhibited a significant linear FAD size effect (P = 0.0272, 0.001, respectively). Associations with drifting objects may allow prey fishes which have habituated to an object to escape predation by capitalizing on a reflexive avoidance of the object by a pursuing predator.

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