Rhynchobatus sp. nov. A

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA CHONDRICHTHYES RAJIFORMES RHYNCHOBATIDAE

Scientific Name: Rhynchobatus sp. nov. A
Common Name(s):
English Roughnose Wedgefish
Taxonomic Notes: An undescribed but distinct species. Rhynchobatus sp. A is not part of the Indo-West Pacific Rhynchobatus djiddensis species complex (which includes R. djiddensis sensu stricto, R. australiae, Rhynchobatus sp. nov. B, and possibly R. laevis), but may be more closely related to the eastern Atlantic R. luebberti (Compagno and Last 1999).

Assessment Information [top]

Red List Category & Criteria: Vulnerable A2ad+3d+4ad ver 3.1
Year Published: 2006
Date Assessed: 2006-01-31
Assessor(s): Compagno, L.J.V. & Marshall, A.D.
Reviewer(s): Kyne, P.M., Heupel, M.R. & Simpfendorfer, C.A. (Shark Red List Authority)
Justification:
The undescribed roughnose wedgefish Rhynchobatus sp. nov. A has a restricted and fragmented distribution in coastal waters off northwestern Java (Indonesia) and Singapore. This is a dwarf species of Rhynchobatus reaching 82 cm total length (TL) (whereas other members of the genus can reach 300 cm TL), but little is known of its biology. This species is irregularly caught as bycatch in local fisheries throughout its range but there are also reportedly directed fisheries for this species in both Indonesia and Singapore. Coastal rhynchobatid species, including Rhynchobatus sp. nov. A are highly susceptible to capture in a variety of fishing gear including inshore trawl nets, gill nets and line gear. Its flesh is highly sought after as are its fins, which are sold into the international fin trade. Fishing is intense and generally unregulated throughout the species range and direct observations of bycatch numbers have indicated population declines of this naturally uncommon species. In particular, Indonesia has an extremely high level of exploitation on its marine resources, and this is only likely to increase into the future. Furthermore, there are heavy impacts through habitat degradation/pollution on the species' area of occurrence off Java.

While exact data are unavailable, declines are known to have occurred throughout this species' range, indicated by observed bycatch levels. Actual exploitation levels of the marine environment are intense throughout its distribution, and there is the real potential for increased exploitation as the human population continues to rise in the region, and as demand for the international fin trade only increases. The restricted inshore habitat, susceptibility to capture in various gear types, and ever growing demand place coastal rhynchobatids amongst the most vulnerable chondrichthyan fishes. The situation is heightened with respect to Rhynchobatus sp. nov. A, which has a restricted and fragmented distribution. As such a Vulnerable assessment for Rhynchobatus sp. nov. A is warranted given direct observations of declines, and actual and potential levels of exploitation in the region. Continuing high levels of pressure in the region may result in a higher threat assessment in the future.

Geographic Range [top]

Range Description:Narrow geographic range with a fragmented distribution off northwestern Java (Indonesia) and Singapore in the Western Central Pacific.
Countries:
Native:
Indonesia (Jawa); Singapore
FAO Marine Fishing Areas:
Native:
Pacific – western central
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population: An uncommon species (Compagno and Last 1999). Observations of bycatch numbers have indicated population declines. Additional catch data and observations need to be made.
Population Trend: Decreasing

Habitat and Ecology [top]

Habitat and Ecology: An inshore species, benthic in coastal waters. This is a "dwarf" species of Rhynchobatus, reaching 82 cm TL (whereas other members of the genus reach 300 cm TL). Aplacental viviparous, but little is known of the species' biology.

Life history parameters
Age at maturity (years): Unknown.
Size at maturity (total length): Female: >69 cm TL (Compagno and Last 1999); Male: Adolescent 65 cm TL, adult 71 cm TL (Compagno and Last 1999).
Longevity (years): Unknown.
Maximum size (total length): 82 cm TL (Compagno and Last 1999).
Size at birth: 21 to 24cm TL (Compagno and Last 1999).
Average reproductive age (years): Unknown.
Gestation time (months): Unknown.
Reproductive periodicity: Unknown.
Average annual fecundity or litter size: Unknown.
Annual rate of population increase: Unknown.
Natural mortality: Unknown.
Systems: Marine

Threats [top]

Major Threat(s): The restricted inshore habitat, limited life history characteristics, susceptibility to capture in various gear types, and ever growing demand place coastal rhynchobatids amongst the most vulnerable chondrichthyan fishes. The situation is heightened with respect to Rhynchobatus sp. nov. A which has a restricted and fragmented distribution.

This species is irregularly caught as bycatch in local fisheries throughout its range but there are also reportedly directed fisheries for this species in both Indonesia and Singapore. Coastal rhynchobatid species, including Rhynchobatus sp. nov. A are highly susceptible to capture in a variety of fishing gear including inshore trawl nets, gill nets and line gear. Its flesh is highly sought after as are its fins, which are sold into the international fin trade. Fishing is intense and generally unregulated throughout the species' range and direct observations of bycatch numbers have indicated population declines of this naturally uncommon species. In particular, Indonesia has an extremely high level of exploitation on its marine resources, and this is only likely to increase into the future.

Habitat modification/degradation, including to inshore nursery areas, from human activities (fisheries, pollution, coastal impacts) are likely affecting this species given its inshore range, particularly off Java, where human pressure on the coastal and marine environment is high.

Conservation Actions [top]

Conservation Actions: No direct conservation actions in place, although the banning of trawling around the island and territorial waters of Singapore is affording this species a limited amount of protection within this immediate area from this type of fishing. It is still, however heavily fished with other methods in that region.

Needs better understanding of habitat requirements and critical area/habitats to establish best amelioration processes.

Harvest and trade management is needed, including control of fin trading activities. Livelihood alternatives may need to be sought for fishing communities.

The development and implementation of management plans (national and/or regional e.g., under the FAO International Plan of Action for the Conservation and Management of Sharks: IPOA-Sharks) are required to facilitate the conservation and management of all elasmobranch species in the region. See Anon. (2004) for progress made by Indonesia towards a National Plan of Action and towards a regional plan of action involving both Indonesia and Singapore.

Bibliography [top]

Anonymous. 2004. Report on the implementation of the UN FAO International Plan of Action for Sharks (IPOA?Sharks). AC20 Inf. 5. Twentieth meeting of the CITES Animals Committee, Johannesburg (South Africa), 29 March?2 April 2004.

Compagno, L.J.V. and Last, P.R. 1999. Rhinidae. In: K.E. Carpenter and V.H.Niem (eds) FAO species identification guide for fishery purposes. The living marine resources of the Western Central Pacific. Volume 3. Batoid fishes, chimaeras and bony fishes part 1 (Elopidae to Linophyrnidae), pp. 1418-1422. FAO, Rome.

IUCN. 2006. 2006 IUCN Red List of Threatened Species. www.iucnredlist.org. Downloaded on 04 May 2006.

IUCN SSC Shark Specialist Group. Specialist Group website. Available at: http://www.iucnssg.org/.


Citation: Compagno, L.J.V. & Marshall, A.D. 2006. Rhynchobatus sp. nov. A. In: The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 23 August 2014.
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