|Scientific Name:||Mustelus henlei|
|Species Authority:||(Gill, 1863)|
Rhinotriacis henlei Gill, 1863
|Taxonomic Notes:||The Brown Smooth-hound was originally described as Rhinotriacis henlei by Gill in 1863. This name was changed to Triakis henlei and then to the currently valid name Mustelus henlei (Gill 1863).
In the past, misidentification has lead to a lack of information about the basic biology of the Mustelus species in the Gulf of California. A recent taxonomic revision of this group in the Northern Gulf of California and off southwest peninsula of Baja California has identified a fourth smooth-hound species (Castro-Aguirre et al. 2005, Pérez-Jiménez et al. 2005)).
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor(s):||Pérez-Jiménez, J.C. & Carlisle, A.B.|
|Reviewer(s):||Stevens, J.D., Pollard, D., Dudley, S. & Valenti, S.V. (Shark Red List Authority)|
A small common to abundant shark, occurring from Coos Bay, Oregon, USA to the Gulf of California, Mexico in the Eastern Central Pacific and from Ecuador to Peru in the Southeast Pacific. Found from the intertidal region to 278 m depth, and very common in enclosed, shallow muddy bays. Although the species is heavily fished in areas of the Gulf of California, there is apparently no evidence to indicate that the population has undergone significant decline. The species is not commercially fished off California, but is taken as bycatch and by recreational anglers (but not in significant numbers). It is not thought that the species is being over-fished off the USA. This is a fast growing species, with low longevity, early age at first maturity and with a relatively high fecundity, giving it a high capacity for recovery from fishing pressure. These life history characteristics combined with the fact that there have been no suspected, observed, or inferred declines in catches or populations in any region for M. henlei justify an assessment of Least Concern at present.
|Range Description:||Eastern central Pacific: Coos Bay, Oregon, USA to Gulf of California, Mexico (Eschmeyer et al. 1983). Southeast Pacific: Ecuador and Peru (Compagno in prep.).
This is one of the most commonly found sharks in bays and estuaries, particularly in San Francisco, Tomales, and Humboldt Bay (Compagno 1984, Love 1991). Nursery areas have been reported from central and northern California, specifically in Tomales Bay (Bane and Bane, 1971), San Francisco Bay (De Wit 1975, Yudin 1987) and Humboldt Bay (Yudin 1987). At the moment there are no known nursery areas for M. henlei in the Gulf of California.
Native:Ecuador; Mexico; Peru; United States (California, Oregon)
|FAO Marine Fishing Areas:||
Pacific – eastern central
|Lower depth limit (metres):||266|
|Upper depth limit (metres):||1|
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||A common to abundant shark where it occurs. The microdistribution and population structure of this species may be very localized and spotty (Compagno in prep.). It is locally abundant in bays north of Monterey, California, with extensive populations in San Francisco, Tomales, and Humbolt bays (Castro 1996). No decline in catches or population has been observed in any region for M. henlei.|
|Current Population Trend:||Unknown|
|Habitat and Ecology:||An abundant inshore to offshore, cold-temperate to warm-temperate or subtropical bottom-dwelling shark of continental shelves, found from the intertidal region to at least 200 m depth, and very common in enclosed, shallow muddy bays (Compagno 1984). In the northern Gulf of California has been caught from 30-266 m but it is mainly distributed at depths greater than 100 m (Pérez-Jiménez 2006). It is seasonally abundant in inshore estuarine waters during the spring and summer when it pups, but moves offshore during the winter months when salinity drops due to increased freshwater runoff (Compagno 1984, Yudin 1987, Flemming 1999, Ebert 2003). Of the three species of smooth hounds off the west coast of North America, it is the most cold-tolerant, being apparently resident in cold-temperate northern California (Compagno 1984, Compagno in preparation).
It is viviparous, with a yolk sac placenta, and litter sizes range from 1-10 (Compagno 1984, Ebert 2003). They grow quite rapidly during the first few years of life, but growth slows at maturity. Age at maturity is 2-3 years for females and three years for males (Pérez-Jiménez 2006, Yudin and Cailliet 1990). Size at maturity is 51-66 cm total length (TL) for females and 52-66 for males (Pérez-Jiménez 2006, Yudin and Cailliet 1990). Longevity is about 13 years and the species reaches a maximum size of 100 cm TL (Yudin and Cailliet 1990). Reproduction is annual, with a gestation period of 10-12 months (Pérez-Jiménez 2006, Yudin 1987) and litter size ranging from 1-10 off central California (Compagno 1984, Ebert 2003) and 1-21 (average 11) in the northern Gulf of California (Pérez-Jiménez 2006). Size at birth is 19-30 cm TL (De Wit 1975, Pérez-Jiménez 2006, Yudin and Cailliet 1990). Average reproductive age (generation period) is estimated at 4.7 years (Cortés 2000). Annual rate of population increase is 1.163 (95% C.I. 1.021-1.427) (Cortés 2000) and natural mortality is 0.295 (Smith et al. 1998).
The movement patterns appear to be fairly localized, although one individual traveled 96 miles in three months. In the Gulf of California, they exhibit seasonal migrations. They move about in discrete groups of sharks of similar age, size, and sex. In San Francisco Bay, the sex ratio changes over time and space, with females predominating at times (4.5:1) and males predominating at other times (1:4). These sharks are an important prey item for the sevengill shark in Humboldt and San Francisco Bays (Ebert 2003).
Off San Francisco, California parturition period reportedly occurs from March to May (Bane and Bane 1971) or from May to December (De Wit 1975), and between Santa Cruz and San Francisco, California from January to August (Yudin 1987).
Pregnant females with terminal embryos are abundant (sometimes 50% of sampled individuals) northeast and east of Angel de la Guarda Island (Northern Gulf of California) from late January-late April. So, parturition in the northern Gulf of California has been estimated to occur from late January to late April (Pérez-Jiménez 2006).
Because M. henlei is a fast growing species, with low longevity, early age at first maturity (Yudin and Cailliet 1990) and with a relatively high fecundity (1-21 pups every year and more in the largest females, in the northern Gulf of California according to Pérez-Jiménez 2006), it has a high capacity for recovery from fishing pressure (Smith 1998).
The diet of this species in California waters consist of crustaceans, cephalopods, echiuran and polychaete worms, bony fishes and their eggs, tunicates and bivalves (Herald and Ripley 1951, De Wit 1975, Talent 1982, Russo 1975, Haeseker and Czech 1993, Ebert 2003).
Interest to fisheries is considerable (Compagno in prep.). The species is fished commercially in the Gulf of California, Mexico (Compagno in prep.). Off California they are probably taken as bycatch, although there is no commercial fishery for this species (Ebert 2003). They are primarily caught by recreational anglers in San Francisco Bay and elsewhere along the coast, but not in significant numbers (Ebert 2003).
In the northern Gulf of California, Mexico, Mustelus species have been caught by the artisanal fleet since the 1980s (Cudney and Turk 1998) and by medium size trawler vessels since 1996, when 59 shrimp trawler vessels obtained fishing permits to catch finfish and elasmobranch species during the non-shrimp fishing season. This small shark species is also caught as bycatch, although it is believed that only small numbers are caught because the trawling operations for catching shrimp are shallower than the main distribution area of this small shark species (Sustentabilidad y Pesca Responsible en México: Evaluación y manejo 1997-1998).
In the northern Gulf of California it is commonly caught (the highest catches being of 150 kgh-1) in demersal trawlers operating from January to June at depths greater than 100 m, which are targeting Pacific Hake (Merluccius productus). The species is very commonly caught by the artisanal fishery in the upper Gulf of California, which targets "Baqueta" (Epinephelus acanthistius) using bottom set longlines. It is sometimes quite abundant in these catches from November to March (Cudney and Turk 1998). In this region it is less commonly caught in bottom gill-nets.
Marquez-Farias (2000) stated that in the Sonora state (northeastern Gulf of California) M. henlei was the most abundant shark species caught with gill-nets by the artisanal fishery at depths greater than 80 m. This mainly occurs during the autumn and winter months when this, and other small shark species (Rhizoprionodon longurio, M. lunulatus and M. californicus), make seasonal migrations. During this period, catch rates as high as 1,200-1,500 individuals per fishing trip have been reported. In the Pacific, off Santa Rosalillita, Baja California (approximately 400 km south of Ensenada) there are high catch rates of Mustelus species (possibly mainly M. californicus and M. henlei). During the period from May to September of 2001, 4,638 kg of Mustelus species were caught (Rodríguez-Medrano and Almeda-Jauregui 2002).
Various fisheries (mainly artisanal) along the coasts of Ecuador and Peru land sharks, including houndsharks, as bycatch. In some cases sharks have been specifically targeted, however target fisheries for sharks were prohibited in Ecuador in 2004 (see Conservation Measures section).
Catch statistics are generally limited, with inadequate monitoring of fishing activities and landings. Bostock and Herdson (1985) estimated that in the early 1980s small-scale fishers landed some 1,800-2,000 t of sharks per year off Ecuador. Later catch estimates from only a subset of landing ports amounted to ~4,000 t/year for 1993-1995. Martínez (1999) noticed a reduction in shark landings in small-scale coastal fisheries in Ecuador in more recent years when compared with those of the early 1980s.
No specific measures in place.
There is little effective management of inshore fishing activities in Ecuador and Peru. Specific management regulations have been lacking, but the recent development of a shark plan for Ecuador and recently introduced measures should lead to improvements. In Ecuador, Decree 2130 banned target fisheries and fin trade in 2004, but implementation and enforcement was insufficient and fins continued to be exported illegally. The export of fins is not banned in Peru. Subsequently, Decree 486 permitted trade in fins from bycatch, mandated the full utilisation of all shark meat, and required monitoring of all bycatch and a licensing system for the trade of fins. This decree provided an important means of monitoring shark catches.
|Citation:||Pérez-Jiménez, J.C. & Carlisle, A.B. 2009. Mustelus henlei. The IUCN Red List of Threatened Species 2009: e.T161648A5472414. http://dx.doi.org/10.2305/IUCN.UK.2009-2.RLTS.T161648A5472414.en . Downloaded on 13 October 2015.|
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