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Family Hemigaleidae The Weasel Sharks

Family Hemigaleidae The Weasel Sharks. Sara McCutcheon. General Characteristics. Small to medium sized sharks Horizontal, oval eyes w nictitating eyelids Long labial furrows Spiral intestinal valve Strong ventral lobe of caudal fin Wavy dorsal edge of caudal

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Family Hemigaleidae The Weasel Sharks

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  1. Family HemigaleidaeThe Weasel Sharks Sara McCutcheon

  2. General Characteristics • Small to medium sized sharks • Horizontal, oval eyes w nictitating eyelids • Long labial furrows • Spiral intestinal valve • Strong ventral lobe of caudal fin • Wavy dorsal edge of caudal • Upper teeth large and saw-edged • Lower hooked teeth protrude from mouth

  3. Chaenogaleus (1 sp.) Hemipristis (1 sp.) Hemigaleus (2 spp.) Paragaleus (4 spp.) Taxonomy8 species in 4 Genera

  4. Taxonomy 1 Chaenogaleus macrostoma – Hooktooth shark 2 Hemigaleus microstoma – Sicklefin weaselshark 3 Hemigaleus australiensis – Australian weasel shark 4 Hemipristis elongatus – Snaggletooth shark 5 Paragaleus leucolomatus – Whitetip weasel shark 6 Paragaleus pectoralis – Atlantic weasel shark 7 Paragaleus randalli – Slender weasel shark 8 Paragaleus tengi – Straighttooth weasel shark

  5. Habitat • Continental and insular shelves • Tropical and subtropical waters • Depths range from shallow to 170 m • Demersal • Benthopelagic • Coastal

  6. Distribution • Indo-West Pacific for 7 species • East Atlantic for Paragaleus pectoralis

  7. Reproductive Biology • Viviparous with yolk-sac placenta • Minimum population doubling time more than 14 years • Fecundity ranging from 1-19 • Gestation time of 6 months to one year • Biennial or triennial reproductive cycles Mate in March-May and parturition in May-June

  8. Diet • Varied diet • Feed on cephalopods, crustaceans, and small fish • Some are specialist feeders of cephalopods, especially octopus • Hemipristis elongatus also feeds on sharks and rays • Some live in reefs and weedy areas for prey

  9. Fisheries • Common and important in fisheries • Taken regularly in inshore artisanal fisheries • Intensive and largely unmanaged net and trawl fisheries occur throughout most of the sharks range (except for Australia) • Hemigaleus microstoma is fished in high numbers in SE Asia

  10. Status • Used for human consumption, the liver is processed fro vitamins, fins for oriental shark fin trade, and by-products for fishmeal • Thought to have a very low resilience to fishing, with a maximum population doubling time of more than 14 years • Most are considered harmless to humans • Hemipristis elongatus is considered potentially dangerous because of large teeth and shallow habitat

  11. IUCN Red List • Hemigaleus microstoma listed as least concern • Hemipristis elongatus is listed as vulnerable except in Australia (Least Concern) • Chaenogaleus macrostoma, Paragaleus leucolomatus, Paragaleus pectoralis, Paragaleus randalli, and Paragaleus tengi are not in IUCN Red List

  12. Bibliography Bass, A.J., Heemstra, P.C., and Compagno, L.J.V. 1986. Carcharhinidae. P. 67-87. In M.M. Smith and P.C. Heemstra (ed.s) Smith's sea fishes. Springer-Verlag, Berlin. Carrier, J.C., Musick, J.A., and Heithaus, M.R.. 2004. Biology of Sharks and their Relatives. CRC Press, Boca Raton, FL. pp. 51, 73. Compagno, LJV. 1984. FAO Species Catalogue, Vol 4. Sharks of the World. An annotated and illustrated catalogue of shark species known to date. Part 2 – Carcharhiniformes. FAO Fish. Synop. 125 (4/2):251-655. Compagno, L, M. Dando, and S. Fowler. 2005. Sharks of the World. Princeton University Press, Princeton, NJ. pp. 283-287. Nelson, J.S. 2006. Fishes of the World, 4th ed. John Wiley and Sons, Inc, NJ. p. 62. Simpendorfer, CA, 2003. Hemigaleus microstoma. In: IUCN 2007. 2007 IUCN Red list of Threatened Species. www.iucnredlist.org. Downloaded on 24 October 2007. White, W.T. 2003. Hemipristis elongatus. In: IUCN 2007. 2007 IUCN Red List of Threatened Species. www.iucnredlist.org. Downloaded on 24 October 2007. White, W.T., Last, P.R., and Compagno, L.J.V. 2005. Description of a new species of weasel shark, Hemigaleus australiensis n.sp. (Carcharhiniformes: Hemigaleidae) from Australian waters. Zootaxa 1077:27-49. Capape C, Diatta Y, Diop M, Reynaud C, Guelorget O. New data on the reproductive biology of the Atlantic weasel shark, Paragaleus pectoralis (Chondrichthyes : Hemigaleidae) from the coast of Senegal (eastern tropical Atlantic). CYBIUM 29 (4): 363-371.

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