Using carapace measurements to determine the sex of Antarctic krill, Euphausia superba

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Goebel, M. E., Lipsky, J. D., Reiss, C. S., & Loeb, V. J. (2007). Using carapace measurements to determine the sex of Antarctic krill, Euphausia superba. Polar Biology, 30(3), 307-315. doi:10.1007/s00300-006-0184-8
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TitleUsing carapace measurements to determine the sex of Antarctic krill, Euphausia superba
AuthorsE. Goebel, D. Lipsky, S. Reiss, J. Loeb
AbstractKrill (Euphausia superba) carapace measurements (length and width; mm) collected from plankton tows in the South Shetland Islands (SSI), Antarctica are used to test the generality of a common discriminant function developed to reconstruct krill length frequencies in Antarctic fur seal diets for the area surrounding South Georgia (SG). Total length and sex ratio of krill in the SSI were overestimated by 5.6 and 154%, respectively, when the SG allometric equations were applied to 3 years (2003-2005) of data. These errors arise and increase as a result of krill population dynamics, specifically recruitment that contributes large proportions of immature krill, misclassified as males by the SG discriminant function. We develop sex-specific regression models based on separate discriminant functions that provide significantly better discriminatory power. However, our analysis indicates that reconstructions of krill sex ratio and length composition in the ocean environment are less reliable in years when the ratio of immature to mature krill is high. For the SSI area, five out of 14 years (35.7%) surveyed (1992-2005) had proportions of immature to mature adult krill ≥ 0.50. © 2006 Springer-Verlag.
JournalPolar Biology
Date2007
Volume30
Issue3
Start page307
End page315
ISSN07224060
Subjectsallometry, crustacean, diet, discriminant analysis, measurement method, numerical model, pinniped, population dynamics, sex ratio, Antarctica, South Georgia, South Shetland Islands, Arctocephalus gazella, Decapoda (Crustacea), Euphausia superba, Euphausiacea
NoteCited By (since 1996):2, CODEN: POBID

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