Density Dependant Sex Change in Northern Shrimp, Pandalus borealis, on the Scotian Shelf

P. Koeller, R. Mohn and M. Etter

Department of Fisheries and Oceans, Bedford Institute of Oceanography
P. O. Box 1006, Dartmouth, Nova Scotia, Canada B2Y 4A2

 

Source - Journal of Northwest Atlantic Fishery Science, Volume 27:107-118
ISSN-0250-6408

P. Koeller, R. Mohn and M. Etter. 2000. Density Dependant Sex Change in Northern Shrimp, Pandalus borealis, on the Scotian Shelf. J. Northw. Atl. Fish. Sci. 27: 107-118. https://doi.org/10.2960/J.v27.a10

We investigated factors affecting sex change in the Pandalid shrimp Pandalus borealis on the Scotian Shelf. Transition from male to female occurred at different sizes and ages, and could not be related to a minimum size or age. Our data did not show a positive relationship between abundance of older females and shrimp size at sex transition, nor a negative relationship between male:female sex ratio and shrimp size at transition, that would be expected if the population was compensating for decreases in reproductive capacity as predicted by sex allocation theory. Size at transition was inversely related to female density, which was attributable to density dependent growth affecting all stages. Density dependant growth also appeared to explain previously reported results which had been used to support sex allocation theory. Density was the most important factor determining individual growth at high densities while at low densities other factors, including temperature, were also an important determinant of growth. We conclude that a decrease in the size at transition can be indicative of a healthy, as well as a declining stock, and must be fully understood before it can be used as an indicator of stock status. Possible alternative mechanisms for regulating sex change in Pandalids are discussed.

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Language - English
Publisher - Northwest Atlantic Fisheries Organization (NAFO), Dartmouth, N.S., Canada
Publication Date - December 2000
Publication Type - Journal Article

Citation: P. Koeller, R. Mohn and M. Etter. 2000. Density Dependant Sex Change in Northern Shrimp, Pandalus borealis, on the Scotian Shelf. J. Northw. Atl. Fish. Sci. 27: 107-118. https://doi.org/10.2960/J.v27.a10