Myliobatis tenuicaudatus

Taxonomy

Assessment Information

Geographic Range

Population

Habitat and Ecology

Threats

Conservation Actions

Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
ANIMALIA	CHORDATA	CHONDRICHTHYES	RAJIFORMES	MYLIOBATIDAE

Scientific Name:

Myliobatis tenuicaudatus

Species Authority:

Hector, 1877

Common Name/s:

English

–

New Zealand Eagle Ray, Whiptail Ray

Taxonomic Notes:

May be conspecific with Myliobatis australis Macleay, 1881 from southern Australia. If so the name M. tenuicaudatus has precedence (Last and Stevens 1994).

Assessment Information [top]

Red List Category & Criteria:	Least Concern ver 3.1
Year Assessed:	2003
Assessor/s	Duffy, C. (SSG Australia & Oceania Regional Workshop, March 2003)
Evaluator/s:	Kyne, P.M. & Cavanagh, R.D. (Shark Red List Authority)
Justification: A common coastal species, Myliobatus tenuicaudatus is endemic to New Zealand. Little is known of its reproductive biology, but it may be relatively productive (one captive female gave birth to 20 pups). Although taken in a wide variety of fisheries this species is usually released or discarded, and appears to survive capture and release well. It is prohibited as a commercial target species in quota management areas encompassing the core of its distribution.

Geographic Range [top]

Range Description:	Kermadec Islands; Three Kings Islands; North and South Island to Foveaux Strait (including Fiordland); Chatham Rise (not recorded from Chatham Islands).
Countries:	Native: New Zealand (Kermadec Is., North Is., South Is.)
FAO Marine Fishing Areas:	Native: Pacific – southwest

Population [top]

Population:	Rare at the Kermadec Islands. Uncommon south of Cook Strait and the Marlborough Sounds. Rare on the Chatham Rise.
Population Trend:	Unknown

Habitat and Ecology [top]

Habitat and Ecology:	A common coastal species. Found mainly over soft bottoms, including tidal flats in estuaries and harbours, also commonly encountered on shallow rocky reefs. They are present in shallow water all year round but tend to concentrate in water less than about 10 m deep during summer and autumn, and move offshore into water deeper than 20 m during winter. Only adults and large juveniles are found in shallow water. Occur from low water to 422 m but is rare below about 50 m. Usually encountered on or near the bottom, eagle rays are occasionally seen swimming at the surface in open water. They are predators of hard-shelled benthic invertebrates. Those found on reefs feed mainly on gastropods, particularly Cook’s turban (Cookia sulcata) and hermit crabs. Those inhabiting soft bottoms feed on a variety of bivalves, small crustaceans (including crabs and shrimps) and polychaete worms. Eagle ray feeding pits are a common feature of tidal flats in many North Island harbours and they may play an important role in structuring intertidal sand flat communities. Reproduction is viviparous. Litter size and size at birth is poorly known. A captive female gave birth to a litter of 20 pups after six months in captivity. Disc length at birth was reported to be about eight centimeters. After 16 months two surviving juveniles were about 15 cm disc length (pers. obs). Size at maturity is unknown. Maximum total length is about 200 cm. Predators include killer whales and white shark (Carcharodon carcharias).
Systems:	Marine

Habitat and Ecology:

A common coastal species. Found mainly over soft bottoms, including tidal flats in estuaries and harbours, also commonly encountered on shallow rocky reefs. They are present in shallow water all year round but tend to concentrate in water less than about 10 m deep during summer and autumn, and move offshore into water deeper than 20 m during winter. Only adults and large juveniles are found in shallow water. Occur from low water to 422 m but is rare below about 50 m. Usually encountered on or near the bottom, eagle rays are occasionally seen swimming at the surface in open water. They are predators of hard-shelled benthic invertebrates. Those found on reefs feed mainly on gastropods, particularly Cook’s turban (Cookia sulcata) and hermit crabs. Those inhabiting soft bottoms feed on a variety of bivalves, small crustaceans (including crabs and shrimps) and polychaete worms. Eagle ray feeding pits are a common feature of tidal flats in many North Island harbours and they may play an important role in structuring intertidal sand flat communities. Reproduction is viviparous. Litter size and size at birth is poorly known. A captive female gave birth to a litter of 20 pups after six months in captivity. Disc length at birth was reported to be about eight centimeters. After 16 months two surviving juveniles were about 15 cm disc length (pers. obs). Size at maturity is unknown. Maximum total length is about 200 cm. Predators include killer whales and white shark (Carcharodon carcharias).

Systems:

Marine

Threats [top]

Major Threat(s):	Mainly taken as bycatch in inshore trawl fisheries around the upper North Island. Usually discarded. Also taken in Danish seine. Commonly taken by recreational line fishers, either by surfcasting or line fishing from boats. Also taken on set lines, and in drag and set nets. Sometimes speared, or harpooned for sport. Usually released but sometimes retained for their flesh, or for angling competitions. They probably survive capture and release well. A small number of eagle rays are caught for exhibition in public aquaria.

Major Threat(s):

Mainly taken as bycatch in inshore trawl fisheries around the upper North Island. Usually discarded. Also taken in Danish seine. Commonly taken by recreational line fishers, either by surfcasting or line fishing from boats. Also taken on set lines, and in drag and set nets. Sometimes speared, or harpooned for sport. Usually released but sometimes retained for their flesh, or for angling competitions. They probably survive capture and release well. A small number of eagle rays are caught for exhibition in public aquaria.

Conservation Actions [top]

Conservation Actions:	Prohibited as a commercial target species in quota management areas (QMA) 1, 4 and 9. QMAs 1 and 9 represent the core of the species distribution.

Conservation Actions:

Prohibited as a commercial target species in quota management areas (QMA) 1, 4 and 9. QMAs 1 and 9 represent the core of the species distribution.

Citation:	Duffy, C. 2003. Myliobatis tenuicaudatus. In: IUCN 2008. 2008 IUCN Red List of Threatened Species. <www.iucnredlist.org>. Downloaded on 09 January 2009.
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