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MEPS prepress abstract   -  DOI: https://doi.org/10.3354/meps13239

Incorporating Depth into Habitat Use Descriptions for Sailfish (Istiophorus platypterus) and Habitat Overlap with other Billfishes in the Western North Atlantic

Walter J. Bubley*, Benjamin Galuardi, Amy W. Dukes, Wallace E. Jenkins

*Corresponding author:

ABSTRACT: Sailfish, Istiophorus platypterus, is a circumglobal billfish species. The species is commonly targeted in the recreational fishery and by-catch in the commercial fishery, and fishery management would benefit from an enhanced understanding of basic patterns of daily and seasonal movements. Between 2002 and 2007, 87 billfish were tagged with pop-off satellite archival tags in the Atlantic waters off the coast of South Carolina, USA, including sailfish (n = 54), blue marlin, Makaira nigricans (n = 15), and white marlin, Kajikia albida (n = 18). Only fishes meeting specific tag program criteria and length of tag attachment were selected for further analysis (sailfish n=19; blue marlin n=4; white marlin n=3). Differential movement patterns, both horizontally and vertically, were observed within sailfish by season. Two and three-dimensional analyses showed differential spatial niche use within sailfish. Among the istiophorid species, three-dimensional analysis showed less overlap when occupying similar horizontal areas. The results from this study, in conjunction with similar studies from other areas, provide a better understanding of habitat usage that can be applied to address uncertainties in ecology or management, such as characterization of stock structure, identifying potential spawning habitat or intra-specific competition, providing correction factors for indices of abundance, and characterizing vulnerability to fishing gear.