Catch rates declined during the height of the drift net fishery, suggesting that blue shark populations were dropping. Depending on how much allowance is given to improving longline fishing techniques, statistical reviews of the 1990s data indicates that shark populations have now risen, Kleiber said. Even if researchers assume the effectiveness of longline fishing has increased dramatically, the figures show shark populations rising. If fishing efficiency is presumed to be roughly level over time, shark populations appear to have returned to pre-drift net levels, he said. Kleiber said blue sharks are among the most resilient of shark species.
Many shark species mature late in life, and produce comparatively few young.
But blues mature early and can produce 30 to 35 pups at a time, with some births generating more than 100 at a time. Much of the outcry over the overfishing of sharks is the result of the decline in populations of coastal shark species, and from public outcry over stories about fishing crews chopping the fins off sharks and tossing them back into the sea to die. Dried shark fins are popular food items in Asian cuisine. The U.S. House of Representatives earlier this month voted 390 to 1 to ban shark finning in U.S waters and to ban the importing of shark fins. The Senate has not taken up the issue yet.