The decline in shark populations around the world has been a hot topic of concern in recent years due to issues of overfishing and the abysmal treatment of sharks harvested for their fins and other body parts. Today we are going to talk about a very particular species of shark and its history as a harvested fish: the Tope Shark (Galeorhinus galeus), more commonly known as the Soupfin Shark.
The Soupfin Shark ranges worldwide in temperate waters. You can even find them off the coast of California. This shark is highly migratory and can be found in schools of up to 50 individuals. The Tope can reach a length of 6.5 feet, weighing up to 100 pounds. Not only are their fins considered to be a greatly desired commodity, but their skin is used for leather and their liver contains oil that is rich in vitamin A.
Between 1936 to 1944, there were over 24 million pounds of Soupfin Sharks fished in the US, caught mainly for harvesting of the livers. Before 1936, vitamin oils were extracted from cod liver and traded abroad. However, with the dawn of World War II, the exportation of cod liver oils declined and resulted in the rise in demand for oil derived from Soupfin Shark livers. The fishery for Soupfin oil eventually saw a decline, in part because of overfishing, but primarily due to the invention of synthetic vitamins. Due to the International Union for Conservation of Nature Red List, Soupfin Sharks are considered a vulnerable species, making them protected. In California, gillnets are prohibited for use by fishermen and this is a positive change; still, because there is not enough information on stock assessment for these sharks along the California Coast, it is difficult to know how this has affected the population of this at-risk shark.
You can do your part in protecting vulnerable and endangered shark species by learning about sustainability practices of companies whose products that you buy.
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Edited by KC O’Shea
Photography: D P Wilson and Doug Perrine courtesy of ARKIVE
http://www.montereybayaquarium.org/animal-guide/fishes/soupfin-shark
http://www.flmnh.ufl.edu/fish/Gallery/Descript/topeshark/topeshark.html
Cailliet, G.M., D.B. Holts, and D. Bedford. 1992. A review of the commercial fisheries for sharks on the west coast of the United States. In: Shark Conservation: Proceedings of an International Workshop on the Conservation of Elasmobranchs. Eds. J. Pepperell, J. West, and Peter Woon. Pp. 13-29.
Ebert, D.A. 1986. Observations on the elasmobranch assemblage of San Francisco Bay. Calif. Fish Game, 72 (4): 244-249.
Ripley, W.E. 1946. The biology of the soupfin, Galeorhinus zyopterus. Calif. Fish and Game, Fish Bull. no. 64, 96 pp. Roedel, P.M. and W.E. Ripley 1950. California sharks and rays. Calif. Fish and Game, Fish Bull. no. 75, 88 pp.
http://webcache.googleusercontent.com/search?q=cache:5knZ_QY5d9AJ:https://nrm.dfg.ca.gov/FileHandler.ashx%3FDocumentID%3D34352+&cd=9&hl=en&ct=clnk&gl=us
Walker, T.I., Cavanagh, R.D., Stevens, J.D., Carlisle, A.B., Chiaramonte, G.E., Domingo, A., Ebert, D.A., Mancusi, C.M., Massa, A., McCord, M., Morey, G., Paul, L.J., Serena, F. & Vooren, C.M. 2006. Galeorhinus galeus. The IUCN Red List of Threatened Species. Version 2015.2. <www.iucnredlist.org>. Downloaded on 03 August 2015.
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