|Scientific Name:||Haploblepharus edwardsii|
|Species Authority:||(Schinz, 1822)|
Squalus edwardsii Schinz, 1822
|Taxonomic Notes:||A recent taxonomic revision of this genus highlighted that H. edwardsii is commonly misidentified for other Haploblepharus species, resulting in a reduction in H. edwardsii's known range and the possibility that the abundance of this species has been overestimated (Human 2003, 2007).|
|Red List Category & Criteria:||Near Threatened ver 3.1|
|Reviewer(s):||Valenti, S.V. & Fowler, S.L. (Shark Red List Authority)|
Haploblepharus edwardsii was previously considered to range along most of the South African coastline, however, a recent taxonomic revision of the genus has shown that this distribution included those of other Haploblepharus species due to species misidentification. Its current verified range is much smaller than previously thought, with its range lying wholly within heavily fished and potentially degraded inshore waters. That other Haploblepharus species are commonly misidentified for this species, may result in a possible overestimation of abundance for this species. Additionally, there may be population sub-structuring in this species as specimens in the west of its range grow to a smaller maximum size and have different habitat preferences to those in the east of its range. The main threat is recreational fishing where this shark is taken as discarded bycatch, generally regarded as a nuisance by the fishermen, and persecuted as such. The extent of occurrence of this species is estimated to be close to 20,000 km². A continuing decline in the number of individuals and/or quality of habitat is suspected as a result of heavy fishing pressure and pollution and disturbance of inshore waters. Anecdotal observations suggest that these catsharks are highly site specific, suggesting severely fragmented populations. Thus, the species is assessed as Near Threatened, narrowly missing the criteria for Vulnerable B1ab(v,iii).
|Previously published Red List assessments:||
|Range Description:||H. edwardsii is endemic to South Africa, and a recent taxonomic revision has shown that this species occurs from Langebaan Lagoon, Western Cape, to Algoa Bay, Eastern Cape. In the west of its range it prefers shallow rocky reef and kelp forest, however, in the east of its range it prefers deeper water on sandy bottom. This species has been recorded as being abundant, but this may be incorrect due to species misidentification. The extent of occurrence of this species is estimated to be close to 20,000 km².|
|FAO Marine Fishing Areas:||
Atlantic – southeast; Indian Ocean – western
|Lower depth limit (metres):||130|
|Upper depth limit (metres):||1|
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||Previously recorded as abundant, H. edwardii's population size may be overestimated due to misidentification of other species for this species. Different maximum sizes and habitat preferences for this species within its range suggest multiple populations. Anecdotal observations also suggest that these catsharks are highly site specific, suggesting severely fragmented populations. It is likely that at least two populations exist, given that this species grows to a larger size in the east of its range, and the population size and population sub-structuring needs quantifying (Human 2003, 2007).|
|Current Population Trend:||Unknown|
|Habitat and Ecology:||Depth range of this species varies within its range. In the west of its range, it occurs from the intertidal to 30m (pers. obs.) in kelp forests and rocky reefs, whereas in the east of its range it has been recorded from the intertidal, on rocky reef and kelp forest, but is found predominantly on sandy bottom where it has been recorded as deep as 130m (Bass et al. 1975, Human 2003, 2007).
H. edwardsii has an extended single oviparous reproductive strategy and lays two egg cases without an obvious breeding season (Bertolini 1993, Dainty 2002). Size at 50% maturity was given by Bertolini (1993) as about 325 mm TL, for sexes combined, for the False Bay population, and 450 mm TL, for sexes combined, for the Eastern Cape population. Dainty (2002), using an annual vertebral band deposition rate, determined that H. edwardsii is seven years old at 50% maturity for sexes combined, and lives to at least 22 years of age. Bertolini (1993) reported that two egg cases collected by him hatched after three months in an aquarium, and hatching size was 93 mm TL. Egg cases collected by Dainty (2002) had not hatched after seven months. Smith and Griffiths (1997) found that Haploblepharus sharks have a high rate of hatching success (60-75%).
|Major Threat(s):||The main threat is recreational fishing, where this shark is commonly taken as discarded bycatch, generally regarded as a nuisance by the fishermen, and persecuted as such. Survival rates from recreational angling are unknown, although are presumed to be low (Human 2003, 2007). H. edwardsii is used in aquaria, however, there is no directed fishery for this species for the aquarium trade at present (Human 2003, 2007). As with any endemic with a restricted range, it is vulnerable to habitat degradation and loss. It occurs on a heavily utilized and narrow strip of habitat with heavy and increasing human utilization including extensive and intensive recreational diving and sport and commercial fishing, coastal housing development, boating, commercial shipping, and extensive pollution and habitat degradation of inshore environments.|
|Conservation Actions:||No conservation measures are in place for this species at present. The population size needs to be reassessed given its reduced range and previous misidentification of other species for this one. The recent taxonomic revision of this genus should make species identification easier for the genus.|
|Citation:||Human, B. 2009. Haploblepharus edwardsii. The IUCN Red List of Threatened Species 2009: e.T39345A10211065. http://dx.doi.org/10.2305/IUCN.UK.2009-2.RLTS.T39345A10211065.en . Downloaded on 06 October 2015.|
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