Sharks and Fishing
Sharks are found worldwide from the equator to the polar oceans, from the deep ocean depths to shallow nearshore waters, and even some coastal rivers. Sharks vary greatly in their size and form depending upon the habitats in which they live. Most species of sharks are active swimmers and are sleek, streamlined animals. But some lead a more sedentary lifestyle (like nurse sharks, Australia's Wobbegong shark, and others) and do not need to swim actively to pass water over their gills as do most other sharks. With a few specialized exceptions, sharks are opportunistic feeders and predators on fish, invertebrates (squid, octopus, crabs, and others), and sometimes on marine mammals (like seals and sea lions). Whale sharks and basking sharks, which can grow to lengths of over 40 feet and weigh over a ton, feed primarily on microscopic plankton!
Because most species of sharks are predators and occur where people fish, sharks are often caught incidentally by recreational and commercial fishermen. A number of species are known to form aggregations or schools based on age, sex or reproductive status, which almost certainly contributes to their vulnerability to exploitation by fishing. Most sharks are particularly susceptible to overfishing because they grow and mature slowly, are relatively long-lived, and produce small litters. Although many of the larger inshore and pelagic sharks may live for more than 20 years, they may not attain reproductive maturity until their teens or later. Depending on the species, litters typically contain fewer than ten pups and a number of species produce no more than two young in any given litter. Moreover, mature sharks may not reproduce each year. This combination of low reproductive potential, behavioral characteristics which have served sharks well for their survival over millions of years, and the potential for exploitation and overfishing, has caused major concerns among conservation biologists and fishery managers. In past years there have been fisheries directly targeting some sharks, either for food (i.e., meat, sharkfin soup), as sources of vitamin A (before it was synthesized chemically), or for industrial purposes. These directed fisheries in past years were largely unregulated, and some shark populations were overfished to the point where local shark fisheries were no longer economical or collapsed completely. The collapse of former fisheries for shark clearly demonstrated the need for management of this resource. Currently, shark fishing (commercial and recreational) in the United States is highly regulated to help conserve shark populations and maintain the health of our marine ecosystems.
Brown, S.T. (1999). Trends in the Commercial and Recreational Shark Fisheries in Florida, 1980-1992, with Implications for Management. North American Journal of Fisheries Management 19:28-41.
Camhi, M., Fowler, S.L., Musick, J.A., Bräutigam, A., and S.V. Fordham (1998). Sharks and their relatives-Ecology and Conservation. IUCN/SSC Shark Specialist Group. IUCN, Gland, Switzerland and Cambridge, U.K.
Castro, J.I. 2011. Sharks of North American Waters. Oxford University Press, New York, NY. 613 p.
Hart, T.J., and P.J. Hart (1983). Fisheries Ecology. AVI Publishing Company. Westport. CT.
Gallagher, A.J., Hammerschlag, N., Danylchuk, A.J., and S.J. Cooke (2016). Shark recreational fisheries: Status, challenges, and research needs. Ambio 2017, 46:385-398. Springer.
Klein, N.S., and E.J. Techera (2014). Sharks: conservation, governance and mangagement. Routledge, New York.
Weber, M.L., and S.V. Fordham (1997). Managing shark fisheries: Opportunities for international conservation. TRAFFIC International and Center for Marine Conservation. Washington, DC.
Florida Museum of Natural History, Florida Program for Shark Research
National Marine Fisheries Service Recreational Fisheries Statistics Queries
NOAA Fisheries: Shark Conservation
NOAA Fisheries: Shark Identification Placard
NOAA Fisheries: Northeast Fisheries Science Center: Apex Predators Program