Dogfish research suggests new considerations for fisheries

Two U N E students tag a dogfish

August 05, 2014

Newly published research from University of New England Marine Science Professor James Sulikowski's laboratory on movement patterns of the spiny dogfish (Squalus acanthias) has significant potential impacts on fisheries, catch quotas and the ecosystem. 

Spiny dogfish are assumed to be a highly migratory species, making habitual north-south migrations throughout their northwestern Atlantic United States range. Since they are also assumed to be a benthic (bottom-living) species, their populations are documented by the Northeast Fisheries Science Center (NEFSC) bottom-trawl surveys.

Master’s thesis research conducted by UNE graduate student Amy Carlson ’13 just published in the Public Library of Science-One (PLOS) obtained a detailed understanding of the horizontal and vertical movement dynamics of this species by attaching satellite tags to 40 adult spiny dogfish and tracking them between the northern (Gulf of Maine) and southern (North Carolina) extents of their U.S. geographic range.

The reconstructed movement patterns suggest that these sharks stayed in the region where they were tagged over the course of a year, moving east-to-west in the water column – to cooler waters in the summer and warmer inshore waters in winter – rather than migrating up and down the U.S. coast.  

Significant differences in seasonal temperature and depths between the two regions further substantiate the possibility of separate home ranges between the two groups. In addition, movement within the water column suggests distinct daily patterns and that this shark may not spend as much time on the ocean floor, which would potentially decrease availability to fishing gear that is fished on the benthos. 

The results also suggest that the spiny dogfish movement patterns may take them out of survey range or may be in a different geographic location than where the survey is being conducted at certain times of the year; thus, there is potential for this shark’s population  to be larger than current biomass estimates indicate.  

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