Blacktip reef shark

Marine sharks and rays ‘use’ urea to delay reproduction

Blacktip reef shark

Blacktip reef shark. Photo by Ray in Manila, Flickr.

Urea – the main component of human urine – plays an important role in the timing of maturation of sharks, rays and other cartilaginous fish.

A new study by researchers with the Sea Around Us initiative at the University of British Columbia’s Institute for the Oceans and Fisheries found that high urea concentrations common in cartilaginous fish, particularly oviparous marine species, allow them to mature and begin to reproduce at a larger fraction of their maximal size.

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