Featured Species Friday: Tope Shark (Galeorhinus galeus)

This week’s Featured Species, the Tope Shark (Galeorhinus galeus) has a sad and somewhat surprising story to tell. This relatively small shark is known to aggregate in large schools divided by size and sex (Tricas, et al., 1997). These large schools also earned the tope shark the name the schooling shark. They also made these sharks prime targets for fisheries industries around the world, and you may be shocked to learn in what products these sharks can turn up in.

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Sullivan, D. (Photographer). (2018). Soupfin sharks, also known as tope sharks, are fished for both their fins and liver oil [Digital Image]. Retrieved from https://www.nationalgeographic.com/

In California in the 1930’s, shark landings were relatively low, approximately 270 tons per year. Most of those landings were tope sharks, however tope shark landings were not reported separately from other elasmobranch landings until 1941 (Klimley, 2013).  In the mid 1930’s, a new market placed a high demand on shark fisheries: shark liver oil. Shark livers are highly potent in vitamin A and it can also be used to lubricate machinery, which would be critical before and during World War II. A third of an adult tope shark’s body mass is in its liver. It is a massive organ! These little sharks were harvested in rapid rates as the price rose from $50 per ton in 1937 to $2,000 per ton in 1941. Landings rose from 270 tons a year in the early 1930’s to peak at 4,185 tons in 1939 (Klimley, 2013).  In 1941, when tope shark landings were first reported independently, 2,172 tons were harvested that year.

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L’Elasmogrup, University of Valencia (Photographer). (2016 May). Galeorhinus galeus, immature female caught in Santa Pola [Digital Image]. Retrieved from https://www.shark-references.com/

Shortly after the initial boom of the shark liver industry came the bust. Just a few years following the peak harvest in 1941, landings dramatically declined in 1944 to just 287 tons of tope sharks (Klimley, 2013). This is likely due to the tope shark’s biology. These sharks are ovoviviparous, giving live birth to 6 to 52 pups after 12 months of gestation. Once the female shark gives birth, she won’t be ready to breed again for another one to two years (Tricas, et al., 1997; Walker, 2005). This low reproductive rate makes them vulnerable to overfishing.

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Squalene Good Health Shark Liver oil Extract [Digital Image]. Retrieved from https://www.allworldshops.com/

In 1947 the development of synthesized vitamin A, and the end of World War II in 1945,  dramatically decreased the demand for shark oil, however this industry still exists today. Squalene, another oil found in shark liver, has been widely used in cosmetic products such as foundation and lipsticks, sunscreens, lotions, and several other cosmetic items. Squalene contains tons of fatty acids and antioxidants, which makes it a fantastic moisturizing agent. However, squalene isn’t only found in shark liver. It can also be extracted from plants like wheat germ and olives, but of course it costs companies more money to ethically harvest from plants rather than get their squalene from sharks (Roth, 2018). Several companies in the last few decades have publicly pledged to only use plant based squalane, like Unilever and L’Oréal. As a consumer, if you want to avoid buying, using, and consuming shark squalene, look under the ingredients list. If you see squalene or undescribed squalane it has shark liver oil. If you see “vegetable” or “plant based squalane” it has plant based oils. 

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ScubaDiverGirls (Photographer). (2016 March 14). Tope Sharks in San Diego [Digital Image]. Retrieved from http://scubadivergirls.com/

So what is being done to conserve this species and other targeted by the shark liver oil fisheries? In 2010, the European Union took steps to ban deep-sea targeted fisheries in their waters. However, not many other countries have followed their lead and the industry still takes sharks globally. So it’s up to you as a consumer.

  • Be aware of the products you are buying. Look for the words “vegetable” or “plant based Squalane.” Avoid products that do not qualify their Squalane as plant based, or contain Squalene. 
  • Write to companies that still use shark oil (Squalene) and tell them you as a consumer are holding them accountable. You demand better, more ethical practices.
  • Write to your government Reps. I have links below for US citizens. Let them know that you care about tope sharks being in your products. It goes beyond shark fin soup.

 

David W Dodd (2014 July 25). Shark Diving – Tope Sharks – La Jolla, California [Video Clip]. Retrieved from https://www.youtube.com/

Shark Stats

Authority: Linnaeus, 1758

Family: Triakidae, 46 species

Length: 6 feet ( 2 m)

Weight: Approximately 54 lbs (24.5 kg)

Habitat: Continental shelves, shallow coastal waters, and bays

Depth: Varries greatly from 19 – 360 feet (6 – 110 m)

Reproduction: Ovoviviparous

Gestation: 12 months

Litter Range: 6 – 52 pups

Home Range: Worldwide in temperate waters

Diet: Bony fishes and invertebrates

IUCN Status: Vulnerable; taken by commercial fisheries; some populations considered depleted

(Cuevas, García, & Di Giacomo, 2014; Skomal, 2016)

Thank you for checking out this week’s featured species. If you missed last week’s Featured Species: the Dwarf Lanternshark, I highly recommend that you check out the smallest shark of all.

The new Ocean For Sharks Shop is open! There’s handmade ocean inspired plush animals, canvas paintings, and of course my children’s book, Winifred the Wondrous Whale Shark, available in print and PDF. Be sure to stop by. Remember proceeds benefit shark research and conservation with a donation to Project AWARE!

As always, remember you can make a difference for marine ecosystems by contacting your Congress man or woman and telling them that you care about the quality of our waters! Sharks, rays, and other marine organisms cannot speak or be represented in Congress. They need your voice. Get involved and stand up for sharks. Until next time finatics!

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Featured Image Source

Steve Parish Nature Connect (n.d.). Tope Sharks [Digital Image]. Retrieved from https://www.steveparish-natureconnect.com.au/

Literature Cited

Cuevas, J. M., García, M., & Di Giacomo, E. (2014). Diving behaviour of the critically endangered tope shark Galeorhinus galeus in the Natural Reserve of Bahia San Blas, northern Patagonia. Animal Biotelemetry2(1), 11.

Klimley, A. P. (2013). The biology of sharks and rays. University of Chicago Press.

Parker, S. (2008). The encyclopedia of sharks (2nd ed.). Buffalo, NY: Firefly Books Ltd.

Roth, A. (2018). There might be shark in your sunscreen. Retrieved August 2, 2018, from https://www.nationalgeographic.com/animals/2018/07/sharks-news-cosmetics-squalene-health/

Skomal, G. (2016). The Shark Handbook: The Essential Guide for Understanding the Sharks of the World. (2nd ed.). Kennebunkport, ME: Cider Mill Press.

Tricas, T. C., Deacon, K., Last, P., McCosker, J. E., Walker, T. I., & Taylor, L. (1997). The Nature Company Guides: Sharks and Rays. (L. Taylor, Ed.). Hong Kong: The Nature Company, Time Life Books.

Walker, T. I. (2005). Reproduction in fisheries science. In ‘Reproductive Biology and Phylogeny of Chondrichthyes: Sharks, Batoids and Chimaeras’.(Ed. WC Hamlett.) pp. 81–127.

Next Post

Featured Species Friday: Deepsea Skate (Bathyraja abyssicola)

Previous Post

Featured Species Friday: Dwarf Lanternshark (Etmopterus perryi)

 

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