Centrophorus acus

Taxonomy

Assessment Information

Geographic Range

Population

Habitat and Ecology

Threats

Conservation Actions

Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
ANIMALIA	CHORDATA	CHONDRICHTHYES	SQUALIFORMES	CENTROPHORIDAE

Scientific Name:

Centrophorus acus

Species Authority:

Garman, 1906

Infra-specific Taxa Assessed:

See Centrophorus acus (Western Central Atlantic subpopulation)

Common Name/s:

English	–	Needle Dogfish, Steindachner's Dogfish
French	–	Squale-chagrin Aiguille
Spanish	–	Quelvacho Agujón

Assessment Information [top]

Red List Category & Criteria:	Near Threatened ver 3.1
Year Assessed:	2006
Assessor/s	Horodysky, A.Z. & Burgess, G.H.
Evaluator/s:	Kyne, P.M., Heupel, M.R., Simpfendorfer, C.A. & Cavanagh, R.D. (Shark Red List Authority)
Justification: Centrophorus acus is a poorly known deepwater shark with a limited known distribution in the Western Pacific around parts of Japan, Taiwan and the Philippines. It is also nominally recorded from the Western Central Atlantic and the relationship between these forms needs taxonomic resolution when more specimens are available. Few adult specimens of this large (to at least 161 cm total length) Centrophorus species have been collected. This shark has a potentially low fecundity (based on examination of mature females) and a lengthy maturation (females possibly mature >20 years based on dorsal spine examination). Around Japan and Taiwan this species is taken both in targeted deepwater fisheries for squalene (liver) oil and as bycatch in demersal trawl, longline, dropline and gillnet fisheries. Specific information on catches is not available. The species’ biological attributes, together with its limited distribution, make it highly susceptible to population depletion as with other deepwater dogfish with similar life-history strategies. The vulnerability of Centrophorus species to population depletion from localized fishing has been well documented off the east coast of Australia where trawl fishing has depleted the stocks of several species. As such, C. acus is assessed as Near Threatened globally and there is an urgent need for appraisal of catches of this species where it is landed in Japan and Taiwan, and for the development of appropriate management given the apparent limited life-history characteristics of the species. The (nominal) Western Central Atlantic subpopulation is assessed as Data Deficient due to complete lack of information at this time.

Geographic Range [top]

Range Description:	Known from the Northwest and Western Central Pacific. Nominal from the Western Central Atlantic.
Countries:	Native: French Guiana; Japan; Philippines; Taiwan, Province of China; United States
FAO Marine Fishing Areas:	Native: Atlantic – western central; Pacific – northwest; Pacific – western central

Population [top]

Population:	Locally common in several locations in the western Pacific, including in Suruga Bay, southeastern Honshu, Japan.
Population Trend:	Unknown

Habitat and Ecology [top]

Habitat and Ecology:	Inhabits the outer continental shelves and upper slopes at depths of 150 to 950 m, mostly below 200 m and possibly found as deep as 1,786 m in the Philippines. Nominal C. acus in the Western Central Atlantic have been recorded at 630 to 915 m (Compagno in prep a). Little known of this species biology as few adults have been collected. This is a large species of Centrophorus reaching at least 161 cm TL. Yano and Tanaka (1986) described a 161 cm TL mature specimen with five enlarged (5.5 cm diameter) (ovarian) eggs and enlarged uteri. While exact litter sizes are unknown, the small number of eggs in this specimen suggests a small litter size (Compagno in prep a). This species appears to mature late with females maturing at possibly >20 years (Tanaka 1990). Estimated sizes and ages at maturity are given in the life history parameters (below). Based on stomach fullness, C. acus appears to feed more actively at night (Compagno in prep a). A tracking study in Suruga Bay, Japan showed that tagged sharks exhibited little horizontal movements in the short term and remained mostly at 10 to 50 m above the seabed with peaks in swimming depths at 300 to 400 m and 580 to 620 m (Yano and Tanaka 1986). Life history parameters Age at maturity: Female: possibly >20 yrs. Females still immature at 17 to 18 yrs (Tanaka 1990); Male: ~10 yrs (Tanaka 1990) Size at maturity (total length): Female: Females immature to 154 cm TL, mature at 161 cm TL (Yano and Tanaka 1986); Male: 50% maturity: 100 to 105 cm TL (Yano and Tanaka 1986). Longevity: Females: >20 yrs; Male: Males: 17 yrs (dorsal spine rings), possibly up to 20 yrs (extrapolated from growth curve) (Tanaka 1990). Maximum size (total length): At least 161 cm TL (Yano and Tanaka 1986). Size at birth (cm): Unknown. 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

Habitat and Ecology:

Inhabits the outer continental shelves and upper slopes at depths of 150 to 950 m, mostly below 200 m and possibly found as deep as 1,786 m in the Philippines. Nominal C. acus in the Western Central Atlantic have been recorded at 630 to 915 m (Compagno in prep a).

Little known of this species biology as few adults have been collected. This is a large species of Centrophorus reaching at least 161 cm TL. Yano and Tanaka (1986) described a 161 cm TL mature specimen with five enlarged (5.5 cm diameter) (ovarian) eggs and enlarged uteri. While exact litter sizes are unknown, the small number of eggs in this specimen suggests a small litter size (Compagno in prep a). This species appears to mature late with females maturing at possibly >20 years (Tanaka 1990). Estimated sizes and ages at maturity are given in the life history parameters (below).

Based on stomach fullness, C. acus appears to feed more actively at night (Compagno in prep a). A tracking study in Suruga Bay, Japan showed that tagged sharks exhibited little horizontal movements in the short term and remained mostly at 10 to 50 m above the seabed with peaks in swimming depths at 300 to 400 m and 580 to 620 m (Yano and Tanaka 1986).

Life history parameters
Age at maturity: Female: possibly >20 yrs. Females still immature at 17 to 18 yrs (Tanaka 1990); Male: ~10 yrs (Tanaka 1990)
Size at maturity (total length): Female: Females immature to 154 cm TL, mature at 161 cm TL (Yano and Tanaka 1986); Male: 50% maturity: 100 to 105 cm TL (Yano and Tanaka 1986).
Longevity: Females: >20 yrs; Male: Males: 17 yrs (dorsal spine rings), possibly up to 20 yrs (extrapolated from growth curve) (Tanaka 1990).
Maximum size (total length): At least 161 cm TL (Yano and Tanaka 1986).
Size at birth (cm): Unknown.
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 vulnerability of Centrophorus species to population depletion from localized fishing has been well documented off the east coast of Australia where trawl fishing has depleted the stocks of several species (Graham et al. 2001). Centrophorus acus may be highly susceptible to overfishing as with other deepwater dogfish with similar life-history strategies. In the waters off Honshu, Japan, C. acus is caught in localized bottom longline, dropline, and gillnet fisheries and trawls that target deepwater sharks for squalene (liver) oil. This species is also caught off Taiwan, as bycatch of demersal trawl fisheries, and probably in targeted fisheries for deepwater squaloids (Yano and Tanaka 1983, Compagno, in prep a). Part of the species' known depth range is beyond that of present fisheries. Presently unexploited depths may serve as a refuge for the species, although the extent of this is unknown given the lack of information on any difference in movement patterns, habitat use and depth segregation between sexes/maturity stages, etc. Threats in the Western Central Atlantic are unknown, but may include bycatch in demersal longline fisheries.

Major Threat(s):

The vulnerability of Centrophorus species to population depletion from localized fishing has been well documented off the east coast of Australia where trawl fishing has depleted the stocks of several species (Graham et al. 2001).

Centrophorus acus may be highly susceptible to overfishing as with other deepwater dogfish with similar life-history strategies. In the waters off Honshu, Japan, C. acus is caught in localized bottom longline, dropline, and gillnet fisheries and trawls that target deepwater sharks for squalene (liver) oil. This species is also caught off Taiwan, as bycatch of demersal trawl fisheries, and probably in targeted fisheries for deepwater squaloids (Yano and Tanaka 1983, Compagno, in prep a).

Part of the species' known depth range is beyond that of present fisheries. Presently unexploited depths may serve as a refuge for the species, although the extent of this is unknown given the lack of information on any difference in movement patterns, habitat use and depth segregation between sexes/maturity stages, etc.

Threats in the Western Central Atlantic are unknown, but may include bycatch in demersal longline fisheries.

Conservation Actions [top]

Conservation Actions:	No conservation actions are currently in place. Deepwater squaloids are highly susceptible to population depletion from localized fishing activities. This situation has been well documented with Centrophorus species off the east coast of Australia (Graham et al. 1997). There is thus an urgent need for appraisal of catches of this species where it is landed in Japan and Taiwan, and the development of appropriate management given the apparent limited life-history characteristics of the species.

Conservation Actions:

No conservation actions are currently in place.

Deepwater squaloids are highly susceptible to population depletion from localized fishing activities. This situation has been well documented with Centrophorus species off the east coast of Australia (Graham et al. 1997). There is thus an urgent need for appraisal of catches of this species where it is landed in Japan and Taiwan, and the development of appropriate management given the apparent limited life-history characteristics of the species.

Citation:	Horodysky, A.Z. & Burgess, G.H. 2006. Centrophorus acus. In: IUCN 2008. 2008 IUCN Red List of Threatened Species. <www.iucnredlist.org>. Downloaded on 04 December 2008.
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