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66th Annual
Northeast Fish and Wildlife Conference
Sunday, April 25 - Tuesday, April 27, 2010
Marriott Boston Newton, Newton, Massachusetts |
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Error processing SSI file
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| Title: |
Seasonal Variation in Smooth Dogfish Mustelus canis, Catch and Diet from a Longline Survey in Buzzards Bay, Massachusetts |
| Author(s): |
Dereck Perry, Coastal Lobster Program, Massachusetts Division of Marine Fisheries; Gregory Skomal, Massachusetts Shark Research Program, Massachusetts Division of Marine Fisheries, Martha's Vineyard Marine Research Station |
| Date: |
Tuesday, April 27, 2010 |
| Time: |
11:20 am - 11:40 am |
| Room: |
Lexington |
Abstract:
Cape Cod, Massachusetts is generally regarded as a natural barrier to the northern range of smooth dogfish Mustelus canis, although they have been observed farther north. This study was designed to characterize and quantify the feeding ecology of smooth dogfish where there is significant overlap with higher densities of American lobster Homarus americanus. Consumption of lobster by predators such as smooth dogfish is thought to be extensive in this area, and may have lead to the drastic decline in local abundance of the lobster over the last decade. The survey was conducted from May through October of 2008 in Buzzards Bay, Massachusetts. A total of twelve random stratified stations were sampled each month within three depth strata; 0-10 m, 11-20 m, and >21 m. Preliminary analysis of the 233 dogfish collected found CPUE was greatest in the earlier months of the survey largely because of the abundance of male smooth dogfish. The sex ratio was dominated by males in May and June and then shifted toward females in the summer months. A dramatic decrease in the number of males occurred in July which coincided with peak water temperatures within the bay during the same period. The diet of the smooth dogfish consisted mostly of crustaceans, with lobster, rock crab Cancer irroratus, and mantis shrimp Squilla empusa, being some of the most common prey items. Preliminary analysis suggests that smooth dogfish may be an under estimated predator of the American lobster, but the extent to which they impact the lobster population in Buzzards Bay remains to be determined. |
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