|Scientific Name:||Holohalaelurus punctatus (Gilchrist, 1914)|
Holohalaelurus polystigma (Regan 1921)
Scylliorhinus punctatus Gilchrist, 1914
|Taxonomic Notes:||The genus Holohalaelurus was recently revised (Human 2006). H. polystigma is a junior synonym of H. punctatus (Human 2006). Holohalaelurus polystigma was included in the checklist of chondrichthyans for the subequatorial Africa region (Compagno and Human 2003) because the revision was in progress at the time the list was compiled.|
|Red List Category & Criteria:||Endangered A2abcd+3bcd+4abcd ver 3.1|
|Reviewer(s):||Cavanagh, R.D., Kyne, P.M., Stevens, J.D., Dudley, S., Pollard, D., Fowler, S.L. & Valenti, S.V. (Shark Red List Authority)|
The Whitespotted Izak (Holohalaelurus punctatus) is an endemic species of the southwestern Indian Ocean. Historically it was common in commercial and research bottom trawls made at depths of about 220–420 m in its range, off the KwaZulu-Natal (South Africa) and southern Mozambique coasts. Examination of species-specific data collected for this species by the Oceanographic Research Institute (ORI), Durban, indicates that this shark was common to abundant in the late 1960s and early 1970s, and yet only a single specimen has been collected from this area since 1972 despite recent biodiversity trawl surveys in that region as part of the Coelacanth (Latimeria chalumnae) project. This species was not recorded from more recent FRS Algoa surveys conducted off Mozambique. A single specimen was collected during a Fridtjof Nansen survey cruise off Mozambique during 2007, but other deep demersal sharks were more common. An intensive deep water crustacean fishery operates throughout this species’ bathymetric range (at depths of 100–600 m) off Durban, and extends northwards into southern Mozambique waters. Holohalaelurus sharks from the KwaZulu-Natal and southern Mozambique region are still present in commercial fisheries landings, but apparently only rarely and species identification is not being recorded. Although the reason for the decline in this species is unknown, the available evidence suggests that it appears to have been severely reduced from its former range off South Africa and Mozambique, where it is now assessed as Endangered. Recently an offshore observer program has been launched in South Africa, and observers should be placed on demersal trawlers in the KwaZulu-Natal region, and trained to identify and record all catches of this species. Future surveys should also attempt to locate this shark.
The Whitespotted Izak also occurs off Madagascar where its population status is unknown although its depth range possibly places it beyond the capabilities of local fisheries, thus providing a possible refuge for this species. It is not known if the Madagascar population is separate from the population off southern Mozambique and northeastern South Africa, but it is likely that the deep waters of the Mozambique channel present a migration barrier. Due to complete lack of information from this part of its range, the The Whitespotted Izak cannot be assessed beyond Data Deficient in Madagascar.
|Range Description:||Western Indian Ocean: from northeastern South Africa, southern Mozambique and Madagascar (Human 2003, 2006, Séret 1987). It is highly unlikely that this species occurs off Cape Point, Western Cape Province, South Africa as stated in the literature (Bass 1986, Bass et al. 1975, Compagno 1984).|
Native:Madagascar; Mozambique; South Africa (KwaZulu-Natal)
|FAO Marine Fishing Areas:|
Indian Ocean – western
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||There may be two populations of H. punctatus, one occurring off the coast of South Africa and Mozambique, and the other off Madagascar, however in the absence of data this is speculative.|
This species was historically common in commercial and research bottom trawls made at depths of about 220–420 m in its range, off the KwaZulu-Natal (South Africa) and southern Mozambique coasts (Bass et al. 1975, Bass 1986, Human 2006). Examination of species-specific data collected for this species by the Oceanographic Research Institute (ORI), Durban, indicates this shark was common to abundant in the late 1960s and early 1970s, and yet, only a single specimen has been collected from this area since 1972, despite recent biodiversity trawl surveys in that region as part of the coelacanth (Latimeria chalumnae) project in progress in the region (P. Heemstra, pers. comm., Human, 2006). This species was not recorded from more recent FRS Algoa surveys conducted off Mozambique. A single specimen was collected during a Fridtjof Nansen survey cruise off Mozambique during 2007, but other deep demersal sharks were more common (P. Heemstra pers. comm. 2008). The Oceanographic Research Institute (ORI), Durban data is species-specific and included morphometric data, as well as sketches and notes on the sharks appearance, therefore there is little doubt that these data sheets are referring to H. punctatus.
|Current Population Trend:||Decreasing|
|Habitat and Ecology:||Its known depth range is 220–420 m. Life history is unknown. Males appear to obtain a greater maximum length compared to females, a trait common to Holohalaelurus sharks. Maximum record size for H. punctatus is 34.0 cm TL. Males are immature at 17.6 cm TL, adolescent at 23.5 cm TL, and mature at 29.8–32.6 cm TL. Females are immature at 17.6–22.7 cm TL and adolescent at 23.6 cm TL (Human 2003, 2006). Bass et al. (1975) report a gravid female with a single egg-case in each uterus. Juveniles are unknown for this species and Bass et al. (1975) speculate that they may occur in deeper waters.|
An intensive crustacean trawl fishery exists off of Durban, and extends northwards into southern Mozambique. This deep water (100–600 m) crustacean fishery fishes towards the edge of the continental shelf in the area (Fennessy and Groenveld 1997).
Holohalaelurus sharks from the KwaZulu-Natal and southern Mozambique region are still present in commercial fisheries landings, but apparently only rarely (N. Kistnasamy, pers. comm.), and species identification is not being recorded. It is not known whether the reduced catch is due to fisheries pressure, habitat loss, pollution, or an as yet unidentified threat (Human 2006).
None currently in place. Recently an offshore observer program has been launched in South Africa, and observers should be placed on demersal trawlers in the KwaZulu-Natal region, and should be trained to identify and record all catches of this species (W. Sawer pers. comm. 2008).
Recommend that a habitat assessment for KwaZulu-Natal and southern Mozambique be conducted below 200 m, and the population in Madagascar needs to be assessed and monitored. Madagascar may provide a much needed refuge for this species. Possible bycatch information on this species needs to be sought. Under the FAO International Plan of Action for the conservation and management of sharks (IPOA-Sharks), development of a shark management plan for all chondrichthyans is currently being considered in South Africa (finalisation and implementation of this plan should be considered a matter of priority and great urgency) (Anon 2004).
Bass A.J. 1986. Scyliorhinidae. In: M.M. Smith and P.C. Heemstra (eds), Smiths' Sea Fishes. First Edition., pp. 88-95. Macmillan South Africa (Publishers) (Pty) Ltd., Johannesburg.
Bass, A.J., D’Aubery, J.D. and Kistnasamy, N. 1975. Sharks of the east coast of southern Africa. II. The families Scyliorhinidae and Pseudotriakidae. Investigational Report No. 37. South African Association for Marine Biological Research, Oceanographic Research Institute.
Compagno, L.J.V. 1984. Sharks of the World: an annotated and illustrated catalogue of the shark species known to date. Part 2. Carcharhiniformes. FAO, Rome.
Compagno, L.J.V and Human, B.A. 2003. Checklist of chondrichthyans for the subequatorial African region, Atlantic, Indian, and Antarctic oceans. SRC Technical Report SRC20030718.
Human, B.A. 2006.. A taxonomic revision of the catshark genus Holohalaelurus Fowler 1934 (Chondrichthyes: Carcharhiniformes: Scyliorhinidae), with descriptions of two new species. Zootaxa 1315: 1-56p.
IUCN. 2009. IUCN Red List of Threatened Species (ver. 2009.2). Available at: www.iucnredlist.org. (Accessed: 3 November 2009).
Séret, B. 1987. Halaelurus clevai, sp. n., a new species of catshark (Scyliorhinidae) from off Madagascar, with remarks on the taxonomic status of the genera Halaelurus Gill and Galeus Rafinesque. Special Publication of the JLB Smith Institute of Ichthyology 44: 1-28.
|Citation:||Human, B. 2009. Holohalaelurus punctatus. The IUCN Red List of Threatened Species 2009: e.T161675A5478093.Downloaded on 18 February 2018.|
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