APPEARANCE Anterior margin of head nearly straight. Deep median indentation. Indentations on each side of the head before eye.

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1 Lateral View ( ) Ventral View ( ) APPEARANCE Anterior margin of head nearly straight. Deep median indentation. Indentations on each side of the head before eye. SYNONYMS First dorsal fin extremely large and strongly falcate. Zygaena mokarran (Rüppell, 1837), Zygaena dissimilis (Murray, 1887), Spyrna ligo (Fraser-Brunner, 1950). High second dorsal fin with a strongly concave rear margin. Falcate pelvic fins. Deeply notched posterior anal margin. Dark brown to light grey or olive dorsally. Fades to white ventrally. No fin markings in adults. Juveniles may have dusky second dorsal fin tips. Maximum total length cm. Most adults not above 366cm. The Great Hammerhead Shark is a virtually circumglobal species in tropical and warm temperate coastal waters. In the east Atlantic it is found in Morocco and Senegal, possibly to Guinea and throughout the Mediterranean Sea No Records (Compagno, 1984). Occasional Range Map base conforms with ICES grid squares. The is a large shark with an unmistakeable head shape and first dorsal fin. The leading edge of the cephalophoil has a median indentation and an indentation on each side of the head before the eye. The first dorsal fin is extremely high and strongly falcate, the second dorsal fin is also relatively high with a strongly concave rear margin. The pelvic fins are falcate and the posterior anal margin is deeply notched (Compagno, 1984). Dorsally it is dark brown to light grey or olive. This fades to white ventrally. There are no fin markings in adults but juveniles may have a dusky second dorsal fin tip (Bester, Unknown). The maximum total length is cm, although the majority of adults of both sexes do not exceed 366cm (Compagno, 1984). EN DISTRIBUTION SPK, Squat-headed Hammerhead, Grand Requin-Marteau (Fr), Cornuda Gigante (Es). NE ATL MED COMMON NAMES

2 Supported by: SIMILAR SPECIES Sphyrna lewini, Scalloped Hammerhead Shark Sphyrna zygaena, Smooth Hammerhead Shark (Not to scale)

3 TEETH The teeth are triangular and strongly serrated in both jaws. There are 2 3 symphysial teeth in upper jaw with 17 teeth each side. There are 1 3 symphysial teeth in lower jaw with teeth each side (Bester, Unknown). ECOLOGY AND BIOLOGY HABITAT Predominantly a coastal shark over continental shelves and lagoons, the can be found far offshore to depths of at least 300m. It migrates seasonally, moving towards the poles and cooler waters during the summer months and returning towards the equator during the winter (Bester, Unknown). EGGCASE N/A DIET An opportunistic predator, the seems to prefer stingrays and other batoids, groupers and sea catfishes. Tarpons, sardines, toadfish, porgies, grunts, jacks, croakers, serranids, tongue-soles, boxfishes, porcupine fishes, smooth-hounds (Mustelus spp.) and other sharks, guitarfish, skates, stingrays, cownosed rays, crabs and squid have also been recorded. It appears not to be fazed by the stings of stingrays and catfish and they are often found embedded in its buccal cavity. One individual had around 50 spines in its mouth, throat and tongue (Compagno, 1984). REPRODUCTION Female s mature at a total length of around 210cm, males larger at around 225cm. During the 11 month gestation period the embryos are nourished through a yolk-sac placenta. Parturition occurs during the spring or summer months with litters of 6 42 pups produced, each of which measures 60 70cm total length. The head of these pups is more rounded than that of the adults. Reproduction is biennial. Unlike most shark species, the may routinely mate in the water column. Pairs have been observed ascending during courtship before mating at the surface (Bester, Unknown).

4 Supported by: COMMERCIAL IMPORTANCE The is taken as bycatch and as a target species in longline, fixed bottom net, hook-and-line and pelagic and bottom trawl fisheries. Its fins are highly prized for sharkfin soup, its flesh can be used fresh of preserved for human consumption, its hide can be used for leather, its liver for vitamin rich oil and its carcass can be processed for fishmeal (Denham et al., 2007). THREATS, CONSERVATION, LEGISLATION The is a large, low fecundity coastal species with highly prized fins and high bycatch mortality. As such it is extremely vulnerable to fisheries pressure. In the east Atlantic, population declines of 80% may have occurred in 25 years. In the Gulf of Mexico and northwest Atlantic, declines of at least 90% have occurred and discard mortality is thought to be as high as 90%. In the southwest Indian Ocean, declines in catches of 79% were reported between 1978 and Its status elsewhere is difficult to quantify due to problems in species identification and illegal, unregulated and unreported fishing, but significant declines are likely to have occurred (Denham et al., 2007). IUCN RED LIST ASSESSMENT Endangered (2007). HANDLING AND THORN ARRANGEMENT Handle with care. Powerful jaws and sharp teeth. Abrasive skin.

5 REFERENCES BESTER, C. Unknown. Great Hammerhead. Florida Museum of Natural History. COMPAGNO, L. J. V FAO Species Catalogue, Vol. 4, Part 1: Sharks of the World. An Annotated and Illustrated Catalogue of Shark Species Known to Date. FAO. Rome, Italy. DENHAM, J., STEVENS, J., SIMPFENDORFER, C. A., HEUPEL, M. R., CLIFF, G., MORGAN, A., GRAHAM, R., DUCROCQ, M., DULVY, N. D., SEISAY, M., ASBER, M., VALENTI, S. V., LITVINOV, F., MARTINS, P., LEMINE OULD SIDI, M., TOUS, P., BUCAL, D Sphyrna mokarran. In: IUCN IUCN Red List of Threatened Species. Version Text: Richard Hurst. Illustrations: Marc Dando. Citation Shark Trust; An Illustrated Compendium of Sharks, Skates, Rays and Chimaera. Chapter 1: The British Isles and Northeast Atlantic. Part 2: Sharks. Any ammendments or corrections, please contact: The Shark Trust 4 Creykes Court, The Millfields Plymouth, Devon PL1 3JB Tel: / enquiries@sharktrust.org For more ID materials visit Registered Company No Registered Charity No