Sexual segregation of pelagic sharks and the potential threat from fisheries
- 1Instituto de Investigaciones Marinas CSIC, Eduardo Cabello 6, 36208 Vigo, Spain
- 2CIBIO—Universidade de Porto Campus Agrário de Vairão, Rua Padre Armando Quintas, 4485-668 Vairão, Portugal
- 3Marine Biological Association of the United Kingdom, The Laboratory Citadel Hill, Plymouth PL1 2PB, UK
- 4School of Biological Sciences, University of Plymouth Drake Circus, Plymouth PL4 8AA, UK
- Author for correspondence (dws{at}mba.ac.uk)
Abstract
Large pelagic sharks are declining in abundance in many oceans owing to fisheries exploitation. What is not known however is whether within-species geographical segregation of the sexes exacerbates this as a consequence of differential exploitation by spatially focused fisheries. Here we show striking sexual segregation in the fastest swimming shark, the shortfin mako Isurus oxyrinchus, across the South Pacific Ocean. The novel finding of a sexual ‘line in the sea’ spans a historical longline-fishing intensity gradient, suggesting that differential exploitation of the sexes is possible, a phenomenon which may underlie changes in the shark populations observed elsewhere.
Footnotes
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- Received December 11, 2008.
- Accepted January 12, 2009.
- © 2009 The Royal Society
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