Diet composition of the smooth dogfish (Mustelus canis) in the waters of Long Island, New York, USA

ABSTRACT

Mustelus canis, one of two species in the genus Mustelus found along the Northwest Atlantic coast and the second most abundant shark in the region, is beginning to comprise large portions of by-catch in various commercial fishing industries. This study analysed the gut contents of sharks taken from three locations in Long Island, NY (Long Beach, Shelter Island and Gardiners Bay) to examine sex- and site-specific diet composition. Our study indicates that smooth dogfish in these waters are opportunistic predators, showing a preference for crustaceans (i.e. Cancer irroratus, Libinia spp., Squilla empusa and Upogebia affinis). Dietary niche breadth was found to vary significantly and niche overlap was moderately low between sexes and between sites. While dietary components of M. canis discovered in this study corroborate other studies performed within the Northwestern Atlantic migratory range of M. canis, smooth dogfish diet varies considerably with region and time of year. Thus, future studies should include surveys of distribution patterns for common prey items and studies of caloric components of these prey items.

RESPONSIBLE EDITOR:

• Keiich Sato

KEYWORDS:

• Feeding
• niche breadth
• predation
• stomach contents

Acknowledgements

We thank Howard Reisman and Michael Frisk for their contributions to this research, Rachel Blakey for her guidance in mapping site locations, and two anonymous reviewers for their thoughtful comments on the original manuscript.