Characterization of bycatch in the cannonball jellyfish fishery in the coastal waters off georgia

Abstract

Studies have been conducted in Georgia to examine bycatch in many fisheries, but none has focused on the trawl fishery for can-nonball jellyfish Stomolophus meleagris. Although this fishery is relatively new, it presently ranks in the top three by weight (kg) in Georgia, along with the food shrimp and blue crab Callinectes sapidus fisheries. The purpose of this study was to characterize and quantify the finfish and invertebrate bycatch species in the cannonball jellyfish trawl fishery in Georgia. Between December 2005 and December 2012, observers accompanied commercial fishers utilizing trawl gear to target cannonball jellyfish in the coastal waters off Georgia; a total of 133 tows were sampled. Observed tow duration ranged from 0.15 to 1.22 h, averaging 0.55 h/tow. During the study period, 1,488 finfish and 150 invertebrates were collected, and 13 individuals representing four species of concern were present in the bycatch. The most numerous species were the Harvestfish Peprilus paru (n D 677), Cownose Ray Rhinoptera bonasus (n D 185), Atlantic Bumper Chloro-scombrus chrysurus (n D 179), Butterfish Peprilus triacanthus (n D 175), and blue crab (n D 114). The estimated numbers of captured cannonball jellyfish and bycatch varied monthly and yielded an overall cannonball jellyfish: bycatch ratio of 291:1. Results suggest that bycatch in the cannonball jellyfish fishery is nominal in comparison with other Georgia trawl fisheries (e.g., shrimp trawl fishery) and is dominated by a few species that are known to associate with jellyfish. Information gained in the present study provides fishery managers with the knowledge necessary to better understand the impacts of Georgia’s commercial cannonball jellyfish trawl fishery on other species.