Date of Award

8-2005

Level of Access Assigned by Author

Campus-Only Thesis

Degree Name

Master of Science (MS)

Department

Marine Biology

Advisor

Philip Yund

Second Committee Member

Yong Chen

Third Committee Member

Gary Melvin

Abstract

Almost 40,000 Atlantic herring (Clupea harengus) were tagged in the Gulf of Maine and Southern New England between 2003 and 2004. This study was conducted in order to collect information on the current stock intermixing and migration patterns for Atlantic herring throughout their range. Management of the Atlantic herring US coastal stock complex depends on determining Total Allowable Catch allocations through an understanding of intermixing rates and migration patterns. The last tagging project in US waters ended in the early 1980's before the fishery shifted to using mobile gear offshore and the Georges Bank stock component recovered. Therefore, a new study was warranted so the assumptions of stock intermixing and migration patterns integrated into the management regime could be validated or redefined. Fish were tagged and released in the Gulf of Maine during the summer feeding/spawning period and in Southern New England during the winter feeding period. One hundred fifteen fish were recovered from the five defined spatial strata (Southern New England, Georges Bank, Gulf of Maine, Nova Scotia and New Brunswick) during the two years of this study. A significant portion of these recoveries represented long-distance migrations and extended times at large. Because recoveries were solely dependant on the commercial fishery, a major focus of the analyses for this study was developing an adjustment factor to weight tag returns by catch and effort. The adjusted returns were then used to describe proportional movements between spatial strata. Results from this study indicate that the majority of herring released in the Gulf of Maine either remained or returned to the same area. However, an appreciable percentage of herring (average, 13.5%) released in the Gulf of Maine were recovered in the Southern New England winter fishery and surprisingly in Nova Scotia (average 8%) during the summer fishery. Fish released in Southern New England were primarily recovered in the Gulf of Maine (66%), while approximately 14% were recovered in the same area of release (Southern New England) and in Nova Scotia. These results are important for two reasons, first they show that tagging herring in the context of an offshore fishery pursued by mobile gear is possible and second, that fish are moving in measurable numbers to and from Nova Scotia. Results from this study could have implications for the stock assessment and management of this species. A comprehensive tagging program should be initiated in order to mark hening in proportion to their abundance and distribution. Results from such a program could be used to quantify rather than just describe possible stock intermixing and define persistent migration patterns.

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