Understanding the basis of shortnose sturgeon (Acipenser brevirostrum) partial migration in the Gulf of Maine

Movement of shortnose sturgeon among major river systems in the Gulf of Maine is common and has implications for the management of this endangered species. Directed movements of sixty-one telemetered individuals monitored between 2010 and 2013 were associated with the river of tagging and individual characteristics. While a small proportion of fish tagged in the Kennebec River moved to the Penobscot River (5%), a much higher proportion of fish tagged in the Penobscot River moved to the Kennebec River (66%), during probable spawning windows. This suggests that Penobscot River fish derive from a migratory contingent within a larger Kennebec River population. Despite this connectivity, fish captured in the Penobscot River were larger (~100mm fork length) and had higher condition factors (median Fultonâ s K: 0.76) than those captured in the Kennebec River (median Fultonâ s K: 0.61). Increased abundance and resource limitation in the Kennebec River may be constraining growth and promoting migration to the Penobscot River by individuals with sufficient initial size and condition. Migrants could experience an adaptive reproductive advantage relative to non-migratory individuals.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author