This week’s featured species was once rather common in the Indian and West Pacific Oceans, but is now considered an Endangered species. The Broadfin Shark (Lamiopsis temminckii) is a medium sized shark in the Carcharhinidae family (Skomal, 2016). The broadfin shark is a relatively stout shark with a moderately long snout, wide mouth, and small eyes (Ebert, Fowler, & Dando, 2015). The broadfin shark is named such for their very broad, triangular pectoral fins (Ebert, Fowler, & Dando, 2015).
Within the genus Lamiopsis there are only two species, the broadfin shark (Lamiopsis temminckii) and the broadfin shark’s closest living relative, the Borneo Broadfin Shark (Lamiopsis tephrodes) (Akhilesh, Purushottama, & Kizhakudan, 2017). These two species are typically geographically separated, with the Borneo broadfin shark residing in southeast Asia, and the broadfin shark residing throughout the northern Indian Ocean and the western Pacific Ocean (White, Fahmi, & Dharmadi, 2009; White, Last, Naylor, & Harris, 2010). Beside geographic distribution, there are several physiological differences between these two species. The most obvious differences between the broadfin sharks are the size and positioning of the dorsal fins, and the size of the upper lobe of the caudal fin (White, Last, Naylor, & Harris, 2010). There are also several variations in their dentition, or their teeth morphology. Below, you can see the variations between the two species with the Borneo Broadfin (L.tephrodes) on the left and the Broadfin (L.temminckii) on the right.
The broadfin shark is known to eat a variety of prey items, including crustaceans, mollusks, teleost fishes, and other species (Akhilesh, Purushottama, & Kizhakudan, 2017). To accommodate their wide ranging diet, they have fairly generalized teeth. In the upper jaw, their teeth have broad, triangular teeth with fine serrations in adult individuals. The teeth in the lower jaw are narrower and smoother than the teeth in the upper jaw (Akhilesh, Purushottama, & Kizhakudan, 2017).
The broadfin shark is currently listed as an Endangered species by the International Union for the Conservation of Nature (IUCN) (White, Fahmi, & Dharmadi, 2009). Throughout the Indian Ocean, their habitats are under threat from the removal and destruction of coastal mangrove habitats that are used as nursery habitats for juveniles (Valiela, Bowen, & York, 2001; White, Fahmi, & Dharmadi, 2009). Pollution from terrestrial runoff is another potential issue for all inshore sharks, including the broadfin shark (Knip, Heupel, & Simpfendorfer, 2010). Besides the threats to their habitat, the broadfin shark is taken regularly, though in low numbers, by local fishermen in India, Pakistan, and Indonesia in gillnet and linegear fisheries (White, Fahmi, & Dharmadi, 2009). When the broadfin shark is landed, the meat is utilized for human consumption, the oils from the liver is used for vitamin oils, and the fins are dried for the fin trade (White, Fahmi, & Dharmadi, 2009). Due to their low productivity potential, the broadfin shark is highly vulnerable to overfishing and their rebound potential is rather limited. In recent studies of the species in the Indian Ocean, decreases in average total lengths of the species is suggesting that the the larger, more mature sharks have been targeted and fished (White, Fahmi, & Dharmadi, 2009). It is important to monitor these large predators for the health of the ecosystem because the complete removal of top predators can lead to a trophic cascade of the ecosystem (Estes et al., 2011).
Authority: Müller & Henle, 1839
Family: Carcharhinidae; 59+ species
Length: Up to 5.5 feet (1.68 m)
Weight: Maximum weight unknown
Habitat: Inshore continental shelves
Depth: Maximum depth of 164 feet (50 m)
Reproduction: Placental Viviparous
Gestation: 8 months
Litter Range: 4 – 8 pups
Home Range: Northern Indian Ocean
Diet: Crustaceans, molluscas, and teleost fishes
IUCN Status: Endangered
(White, Fahmi, & Dharmadi, 2009; Ebert, Fowler, & Dando, 2015; Akhilesh, Purushottama, & Kizhakudan, 2017)
Thanks so much for checking out the endangered Broadfin Shark! If you missed last week’s featured species, please be sure to check out the striking Japanese bullhead shark! If there is a species of elasmobranch you’d love to know more about, leave me a comment or send me a message! I would love to do a feature on your favorite species. So connect with me on Instagram and Facebook for even more elasmo fun!
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Conservation legislation needs public support in order to become law and help protect the environment and wildlife. Tell your representatives that you care about environmental and wildlife conservation. It only takes a moment to make a change that will last a lifetime. Until next time finactics!
Featured Image Source
Müller & Henle (Authors). (1838). Broadfin Shark (Lamiopsis temminckii) [Digital Image]. Retrieved from https://commons.wikimedia.org/wiki/File:Carcharias_temminckii_by_muller_and_henle.png
Akhilesh, K. V., Purushottama, G. B., & Kizhakudan, S. J. (2017). Biological observations on the broadfin shark Lamiopsis temminckii (Carcharhiniformes: Carcharhinidae). Journal of fish biology, 91(6), 1721-1729.
Estes, J. a, Terborgh, J., Brashares, J. S., Power, M. E., Berger, J., Bond, W. J., … Wardle, D. a. (2011). Trophic downgrading of planet Earth. Science (New York, N.Y.), 333, 301–306.
Knip, D. M., Heupel, M. R., & Simpfendorfer, C. A. (2010). Sharks in nearshore environments: models, importance, and consequences. Marine Ecology Progress Series, 402, 1–11.
Valiela, I., Bowen, J. L., & York, J. K. (2001). Mangrove forests: One of the world’s threatened major tropical environments. BioScience, 51(10), 807.
White, W.T., Fahmi & Dharmadi (2009). Lamiopsis temminckii. The IUCN Red List of Threatened Species. Retrieved from https://www.iucnredlist.org/species/161570/5454551
White, W. T., Last, P. R., Naylor, G. J. P., & Harris, M. (2010). Resurrection and redescription of the Borneo Broadfin Shark Lamiopsis tephrodes (Fowler, 1905) (Carcharhiniformes: Carcharhinidae). In Descriptions of New Sharks and Rays from Borneo (pp. 45–69). Retrieved from http://prosper.cofc.edu/~sharkevolution/pdfs/Resurrection and redescription.pdf