Males and females of many species voluntarily segregate themselves into different habitats. A team led by David Sims of the Marine Biological Association of the United Kingdom in Plymouth has discovered an apparent 'sex line' dividing the South Pacific population of shortfin mako sharks (Isurus oxyrinchus) rather as the dance floor at a school disco segregates teenagers.
Of 396 mako caught by commercial fishing boats in this region, those pulled up east of 120°W were nearly all female, whereas those west of this longitude were almost all male (pictured on map: black shows capture locations of female sharks; white indicates males). The western area has traditionally been much more heavily fished, so it is possible that a disproportionately large number of males have been removed from the population.
Rights and permissions
About this article
Cite this article
Ecology: Shark sex line. Nature 458, 10 (2009). https://doi.org/10.1038/458010a
Published:
Issue Date:
DOI: https://doi.org/10.1038/458010a
