Benthobatis kreffti

Taxonomy

Assessment Information

Geographic Range

Population

Habitat and Ecology

Threats

Conservation Actions

Bibliography

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Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
ANIMALIA	CHORDATA	CHONDRICHTHYES	RAJIFORMES	NARCINIDAE

Scientific Name:

Benthobatis kreffti

Species Authority:

Rincon, Stehmann & Vooren, 2001

Common Name/s:

English	–	Brazilian Blind Electric Ray
Spanish	–	Arraia Cega

Taxonomic Notes:

Synonym = Benthobatis marcida (Krefft reports on the FRV ?Walther Herwig? captures).

Assessment Information [top]

Red List Category & Criteria:	Vulnerable B1ab(v) ver 3.1
Year Published:	2004
Assessor/s:	Rincon, G.
Reviewer/s:	Musick, J.A., Kyne, P.M., Cavanagh, R.D. & Fowler, S.L. (Shark Red List Authority)
Contributor/s:
Justification: Benthobatis kreffti has an extremely localised and restricted distribution at 400 to 600 m, known only off Santa Catarina State, Brazil with a further single specimen recorded off São Paulo State. Estimated extent of occurrence is about 16,000 km², but is probably less. Often captured in large numbers by the bottom otter trawl fleet for squid in the area. It is likely to have a low intrinsic rate of increase, and poor resilience to depletion as a deepwater species with only one or two embryos per litter. Increased deepwater fishing effort for squid in its very limited range is likely to affect the population in the near future, inferring a potential and probable decline in the number of mature individuals.

Geographic Range [top]

Range Description:	Extremely localised and restricted distribution off southern Brazil. Estimated extent of occurrence about 16,000 km², but probably less.
Countries:	Native: Brazil (Santa Catarina, São Paulo)
FAO Marine Fishing Areas:	Native: Atlantic – southwest
Range Map:	Click here to open the map viewer and explore range.

Population [top]

Population:	It seems to aggregate over polychaete-rich sediments to feed where large numbers are often captured in a single trawl.
Population Trend:	Unknown

Habitat and Ecology [top]

Habitat and Ecology:	This is a deepwater electric ray with a known bathymetrical distribution of 400 to 600 m depth at bottom water temperatures from 8 to 9°C. It feeds mainly on polychaetes and isopod crustaceans, which it unearths from the sediment. Maximum size is around 26 cm total length (TL). Matures at 14 to 15 cm TL (males) and 20 to 21 cm TL (females). Ovoviviparous; number of young one or two per litter; size at birth 0.96 cm TL. May breed year-round since different gestation stages were found in a single capture, but gestation time and reproductive periodicity unknown.
Systems:	Marine

Habitat and Ecology:

This is a deepwater electric ray with a known bathymetrical distribution of 400 to 600 m depth at bottom water temperatures from 8 to 9°C. It feeds mainly on polychaetes and isopod crustaceans, which it unearths from the sediment. Maximum size is around 26 cm total length (TL). Matures at 14 to 15 cm TL (males) and 20 to 21 cm TL (females). Ovoviviparous; number of young one or two per litter; size at birth 0.96 cm TL. May breed year-round since different gestation stages were found in a single capture, but gestation time and reproductive periodicity unknown.

Systems:

Marine

Threats [top]

Major Threat(s):	Captured in large numbers as bycatch by the otter trawl fishery targeting squid Illex argentinus off Santa Catarina. Large catches and stomach contents (with large numbers of polychaetes) are evidence of aggregation over special worm rich sediments in order to feed, making it more vulnerable to the bottom trawl fishery. Increasing bottom trawl effort for squids in the only known area of its distribution is a matter of concern, inferring future declines in the number of mature individuals as fishing effort increases.

Major Threat(s):

Captured in large numbers as bycatch by the otter trawl fishery targeting squid Illex argentinus off Santa Catarina. Large catches and stomach contents (with large numbers of polychaetes) are evidence of aggregation over special worm rich sediments in order to feed, making it more vulnerable to the bottom trawl fishery.

Increasing bottom trawl effort for squids in the only known area of its distribution is a matter of concern, inferring future declines in the number of mature individuals as fishing effort increases.

Conservation Actions [top]

Conservation Actions:	No conservation measures are in effect. Since it seems to aggregate in certain areas to feed, closed areas may be effective to protect these aggregations. The use of bycatch reduction devices seems to be ineffective since the animal is sensitive to any injury due to its thin skin.

Conservation Actions:

No conservation measures are in effect. Since it seems to aggregate in certain areas to feed, closed areas may be effective to protect these aggregations. The use of bycatch reduction devices seems to be ineffective since the animal is sensitive to any injury due to its thin skin.

Bibliography [top]

	IUCN. 2004. 2004 IUCN Red List of Threatened Species. www.iucnredlist.org. Downloaded on 23 November 2004. IUCN SSC Shark Specialist Group. Specialist Group website. Available at: http://www.iucnssg.org/. Rincon, G. 1997. Taxonomia, alimentação e reprodução da raia elétrica cega Benthobatis sp. (Torpediniformes:Narcinidae) no sul do Brasil. M.Sc. thesis. Fundação Universidade de Rio Grande-FURG. 95. Rincon, G., Stehmann, M.F.W. and Vooren, C.M. 2001. Results of the research cruises of FRV 'Walther Herwig' to South America. LXXIV. Benthobatis kreffti n. sp. (Chondrichthyes, Torpediniformes, Narcinidae), a new deep-water electric ray from off South Brazil and the third species of the genus. Archive of Fishery and Marine Research. 49(1):45-60.

IUCN. 2004. 2004 IUCN Red List of Threatened Species. www.iucnredlist.org. Downloaded on 23 November 2004.

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

Rincon, G. 1997. Taxonomia, alimentação e reprodução da raia elétrica cega Benthobatis sp. (Torpediniformes:Narcinidae) no sul do Brasil. M.Sc. thesis. Fundação Universidade de Rio Grande-FURG. 95.

Rincon, G., Stehmann, M.F.W. and Vooren, C.M. 2001. Results of the research cruises of FRV 'Walther Herwig' to South America. LXXIV. Benthobatis kreffti n. sp. (Chondrichthyes, Torpediniformes, Narcinidae), a new deep-water electric ray from off South Brazil and the third species of the genus. Archive of Fishery and Marine Research. 49(1):45-60.

Citation:	Rincon, G. 2004. Benthobatis kreffti. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 22 May 2013.
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