Shark Spotlight Human’s Whaler Shark

Human’s Whaler Shark (Carcharhinus humani

Written by Alexandra Morata

IUCN SSC Shark Specialist Group | Programme Officer

Taxonomy The order Carcharhiniformes includes 300 species from 52 genera and 10 families: Carcharhinidae (Requiem sharks), Galeocerdidae (Tiger Shark), Hemigaleidae (Weasel sharks), Leptochariidae (Barbeled Houndshark), Proscylliidae (Finback catsharks), Pseudotriakidae (False catsharks), Pentanchidae (Deepsea catsharks) and Scyliorhinidae (Catsharks), Sphyrnidae (Hammerhead sharks) and Triakidae (Houndsharks).

Carcharhinus humani (White & Weigmann 2014), commonly known as Human’s Whaler Shark, belongs to the family Carcharhinidae and is one of 35 species in the species-rich Carcharhinus genus. The species was named after the late Dr Brett Human, who contributed to shark research and taxonomy in South Africa and Oman.

Morphology The Human’s Whaler Shark is a relatively small-bodied shark, reaching a maximum of 94.6 cm in total length (TL). It is characterised by its narrow and rounded snout, tall first dorsal fin, and a black blotch on its second dorsal fin. Carcharhinus humani is commonly misidentified for its congener the Whitecheek Shark (C. dussumieri), Indonesian Whaler Shark (C. tjutjot), and Blackspot Shark (C. sealei). However, it can visually be distinguished from C. dussumieri and C. tjutjot when compared with their smoother basal cusplets on their teeth and their narrower and falcate first dorsal fin. Carcharhinus humani is also distinct from C. sealei by the colouration of their second dorsal fins; C. humani has a black blotch on the tip, while C. sealei has most of its fin coloured in black.

Distribution and Range Human’s Whaler Shark has a patchy distribution across the western Indian Ocean. It has been recorded from Bahrain, Kuwait, Mozambique, Seychelles, South Africa, and Yemen (off the Socotra Islands). It is reported from depths between 0 – 43 meters in inshore and offshore waters. However, a Madagascar specimen was found on the surface of a deepwater area (to 1,260 m depth).

Human’s Whaler Shark Carcharhinus humani)

Artwork by Marc Dando | @marc.dando.92

Conservation and IUCN Red List of Threatened Species status Human’s Whaler Shark was assessed as Data Deficient (DD) on the IUCN Red List of Threatened Species due to the lack of information regarding its population, the small number of specimens recorded, and the difficulty in identifying the species in the areas it occurs. This species is likely threatened, considering fishing pressure across its distribution. In the southwestern Indian Ocean, small sharks that occupy the continental shelf, including C. humani, are more susceptible to fishing pressure than other shark species in the region. Furthermore, the Whitecheek Shark (C. dussumieri) is known to be caught in the Arabian/Persian Gulf waters. Since both species have overlapping ranges and are easily confused, it is likely that C. humani is also caught but remains unreported.

There are currently no species-specific management measures directed towards the conservation of C. humani. However, some existing fisheries management measures might benefit the species. For example, shark fishing is banned in Kuwait, and seasonal trawl bans are in place in Kuwait and Bahrain.

References Ebert, D. A., Dando, M., and Fowler, S. (2021) Sharks of the World: A Complete Guide. Princeton University Press. doi.org/10.2307/j.ctv1574pqp Fricke, R., Eschmeyer, W. N. & Van der Laan, R. (eds) (2022) Eschmeyer’s Catalog of Fishes: Genera, Species, References. calacademy.org/scientists/projects/eschmeyers-catalog-of-fishes Electronic version accessed 29 August 2022. Jabado, R.W., Kyne, P. M., Pollom, R. A., Ebert, D. A., Simpfendorfer, C. A., Ralph, G.M., and Dulvy, N.K. (eds.) (2017) The Conservation Status of Sharks, Rays, and Chimaeras in the Arabian Sea and Adjacent Waters. Environment Agency – Abu Dhabi, UAE and IUCN Species Survival Commission Shark Specialist Group, Vancouver, Canada 236 pp Pollom, R., Gledhill, K., Simpfendorfer, C., Jabado, R.W., Moore, A., Elhassan, I. (2019) Carcharhinus humani. The IUCN Red List of Threatened Species 2019: e.T110834677A139929300. dx.doi. org/10.2305/IUCN.UK.2019-3.RLTS.T110834677A139929300.en. Temple, A.J., Wambiji, N., Poonian, C.N.S., Jiddawi, N., Stead, S.M., Kiszka, J.J., Berggren, P. (2019) Marine megafauna catch in southwestern Indian Ocean small-scale fisheries from landings data. Biological Conservation, 230, 113–121 DOI: 10.1016/j.biocon.2018.12.024 White, W.T. & Weigmann, S. (2014) Carcharhinus humani sp. nov., a new whaler shark (Carcharhiniformes: Carcharhinidae) from the western Indian Ocean. Zootaxa, 3821(1), 71–87 DOI: 10.11646/zootaxa.3821.1.5