Reproductive adaptation: a description of claspers of the Spadenose shark and Milk shark from Gujarat

Abstract

To ensure reproductive success, sharks have adapted several strategies. It was observed that male sharks of <em>Scoliodon laticaudus</em> M&uuml;ller &amp; Henle, 1838 and <em>Rhizoprionodon acutus</em> (R&uuml;ppell, 1837) landed along a few centres of Gujarat coast, have highly calcified claspers which morphologically resembled ossified webbed foot. The morphological and anatomical study revealed that the terminal end of the clasper has been modified into an umbrella like organ called rhipidion which probably ensures that the clasper stays within the cloaca of the female until the sperm is delivered. The landed sharks were all mature. This recent observation of catch of many mature individuals near the coastal waters throws some light on the breeding season and breeding area of sharks along Gujarat coast. With episodes of extinction and threat to the existence of several species of sharks today, this reproductive adaptation of the sharks might helps them to survive and sustain adverse conditions.