Potential effects of human activities on billfishes (Istiophoridae and Xiphiidae) in the western Atlantic Ocean

Billfishes (Istiophoridae [sailfish, marlins, and spearfish] and Xiphiidae [swordfish]) spawn in offshore waters, usually far from land, and, except f or sailfish (Istiophorus platypterus), are found inshore only when deep wat er or currents are near shore. Offshore waters are likely to be less affect ed by human activity than coastal waters, where anthropogenic effects are r ather well-documented. However, human activities in oceanic waters can pote ntially affect the spawning behavior, location, and success of adult reprod uctive activity of billfishes as well as the survival, development, feeding , growth, and mortality of larvae,juveniles, and subadults. These activitie s include: (1) mining; (2) OTEC (Ocean Thermal Energy Conversion); (3) oil drilling; (4) radionuclides; (5) sewage wastes; (6) desalinization wastes; (7) agricultural pollution; (8) pesticides and heavy metals; (9) fishing; ( 10) harvesting of sargasso weed; (11) ozone depletion; (12); and (13) coast al development. The various physical, chemical, and biological effects of t hese human activities are discussed, and recommendations offered for field and Laboratory investigations on early life stages.