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Squaliolus laticaudus

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA CHONDRICHTHYES SQUALIFORMES DALATIIDAE

Scientific Name: Squaliolus laticaudus
Species Authority: Smith & Radcliffe, 1912
Common Name(s):
English Big-eye Dwarf Shark, Spined Pygmy Shark
French Squale Nain
Spanish Tollo Pigmeo Espinudo
Synonym(s):
Squaliolus sarmenti di Noronha, 1926
Taxonomic Notes: Seigel et al. (1977) considered Squaliolus sarmenti and S. aliae as synonyms of S. laticaudus. Sasaki and Uyeno (1987) subsequently removed S. aliae from the synonymy as distinct and the genus now contains these two widely recognised species. Squaliolus laticaudus is sympatric with S. aliae in some regions.

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2006
Date Assessed: 2006-01-31
Assessor(s): Kyne, P.M. & Burgess, G.H.
Reviewer(s): Heupel, M.R., Simpfendorfer, C.A. & Cavanagh, R.D. (Shark Red List Authority)
Justification:
Squaliolus laticaudus is one of the world’s smallest sharks reaching a maximum size of 27.5 cm total length. Oceanic, with a widespread warm-temperate and tropical distribution, occurring near land masses generally over continental slopes and avoiding central ocean basins. Little is known of its biology but it is known to undertake diel vertical migrations from depth (~500 m) to ~200 m probably related to prey movements. An absence of identifiable threats (irregularly taken by fisheries due to its small size) and its widespread distribution justifies an assessment of Least Concern.

Geographic Range [top]

Range Description: A widespread oceanic species recorded from many warm-temperate and tropical regions. Range will likely increase as further specimens are recognized. Not recorded from Australian waters, but given its nearly circumtropical distribution, may be recorded there in the future (Kyne et al. 2005).
Countries:
Native:
Argentina; Bermuda; Brazil; France; Japan; Philippines; Portugal (Azores, Madeira); Somalia; Suriname; Taiwan, Province of China; United States
FAO Marine Fishing Areas:
Native:
Atlantic – eastern central; Atlantic – northeast; Atlantic – southwest; Atlantic – western central; Indian Ocean – western; Pacific – northwest; Pacific – western central
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: No knowledge of stock structure or population size. Compagno (in prep. a) reports that Squaliolus species may occur in aggregations as well as single individuals.
Population Trend: Unknown

Habitat and Ecology [top]

Habitat and Ecology: An oceanic species, occurring near landmasses and apparently avoiding central ocean basins. Primarily found over the continental slope at 200–500 m, but can also occur over continental shelves. Avoids the surface. Vertically migrates on a diel cycle from depth during the day to about 200 m at night, probably related to prey movement (Compagno in prep. a).

Little known of its biology, although it is suspected to be yolksac viviparous. Litter size unknown but 12 well-developed eggs have been found in the ovary of a mature female (ovarian fecundity does not always accurately represent actual fecundity and Squaliolus spp. probably have a small litter size) (Compagno in prep. a).

This is one of the world’s smallest shark species, reaching a maximum size of 27.5 cm TL (Compagno in prep. a).

Life history parameters
Age at maturity (years): Unknown.
Size at maturity (total length): Female: 17–20 cm TL; Male: 15 cm TL.
Longevity (years): Unknown.
Maximum size (total length): 27.5 cm TL.
Size at birth: <9 cm TL (smallest specimen reported by Sasaki and Uyeno 1987)..
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): This species is generally too small to be captured in fisheries and there are no identifiable threats to the species. Specimens have been irregularly taken as bycatch in commercial trawl fisheries, i.e., deepwater shrimp in Suruga Bay, Japan (Abe 1962).

Conservation Actions [top]

Conservation Actions: No specific conservation requirements, although distribution needs to be better defined with the collection and documentation of further specimens during oceanic survey work. Research into life history is also required.

Citation: Kyne, P.M. & Burgess, G.H. 2006. Squaliolus laticaudus. The IUCN Red List of Threatened Species. Version 2014.3. <www.iucnredlist.org>. Downloaded on 20 December 2014.
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