The Biology and Ecology of the Silky Shark, Carcharhinus falciformis

Abstract

The silky shark (Carcharhinus falciformis), an inhabitant of coastal and oceanic waters in tropical regions, is among the world’s most abundant and cosmopolitan shark species. It is caught in signi cant numbers in directed shark sheries throughout its range and is an important bycatch in tropical tuna sheries. On the basis of differences in life-history parameters, it is possible to identify at least three distinct populations inhabiting the Northwest Atlantic, the western-central Paci c, and the eastern Paci c. Data from the Indian Ocean are too sketchy to derive conclusions about a distinct population in this area. Silky sharks grow larger and mature at larger sizes in the Northwest Atlantic than in the western-central and eastern Paci c. Many populations mate and give birth during late spring and summer, but others do not have a well-de ned reproductive season. Silky sharks are born after a 9- to 12-month gestation period and are thought to have 1 year of rest between pregnancies. Litter sizes range from 1 to 16 young, but are more commonly of 6–12 young. Estimates of age at maturity range from 4 to 10 years for males and from 7 to 12! years for females; maximum estimated age is 22! years. Given their importance for shing communities worldwide and the increasing trend in shark catches, silky shark populations should be constantly monitored to assure their conservation and wise management