|Scientific Name:||Mustelus henlei|
|Species Authority:||(Gill, 1863)|
Rhinotriacis henlei Gill, 1863
Triakis henlei (Gill, 1863)
|Taxonomic Source(s):||Eschmeyer, W.N., Fricke, R. and Van der Laan, R. (eds). 2016. Catalog of Fishes: genera, species, references. Updated 1 July 2016. Available at: http://researcharchive.calacademy.org/research/ichthyology/catalog/fishcatmain.asp. (Accessed: 1 July 2016).|
|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., Carlisle, A.B., Chabot, C.L., Vásquez, V.E. & Ebert, D.A.|
|Reviewer(s):||Nosal, A.P. & Cordova, J.|
|Facilitator/Compiler(s):||Kyne, P.M., Lawson, J., Walls, R.H.L. & Dulvy, N.K.|
The Brown Smoothhound (Mustelus henlei) is a small, common to abundant shark species, distributed throughout the eastern Pacific (from Washington, USA to Peru). It is found at depths ranging from the intertidal to 278 m, and is very common in enclosed, shallow, muddy bays. Although the species is heavily fished in areas of the Gulf of California, there is no evidence to indicate that the population has undergone significant decline. The species is not commercially fished off California, but is taken in low volumes as bycatch and by recreational anglers. This is a fast growing species, with low longevity, early age at first maturity and with relatively high fecundity, giving it a high capacity for recovery from fishing pressure. The life history characteristics of this species, combined with the fact that there have been no suspected, observed, or inferred declines in catches or populations in any region justify an assessment of Least Concern.
|Previously published Red List assessments:|
The Brown Smoothhound is distributed throughout the eastern Pacific from Washington, USA to Peru (Ebert 2013), meaning that it has the largest distribution of any Mustelus species in the eastern Pacific (Chabot et al. 2015). This is one of the most commonly encountered sharks in bays and estuaries within United States waters, particularly in San Francisco Bay, Tomales Bay, and Humboldt Bay, California (Ebert 2003, Love 2011). 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), Humboldt Bay (Yudin 1987), and possibly Santa Catalina Island (Chabot and Haggin 2014).
Native:Costa Rica; Ecuador; Mexico (Baja California, Baja California Sur, Sonora); Peru; United States (California, Oregon, Washington)
|FAO Marine Fishing Areas:|
Pacific – eastern central; Pacific – southeast
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||No decline in catches or subpopulations has been observed in any region for this shark. This species is recorded in annual catch landing reports released by the California Department of Fish and Wildlife. Reported annual commercial landings ranged from 1.30 to 3.22 tonnes (t) from 2000-2006, and then dropped to <1 t from 2007-2013, and rose again to 1.80 t in 2014 (California Department of Fish and Wildlife 2000-2014).|
In the northern Gulf of California this shark is commonly caught (the highest catches being of 150 kilograms per hour) in demersal trawlers operating from January to June at depths >100 m, which are targeting Pacific Hake (Merluccius productus).
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.
|Current Population Trend:||Unknown|
|Habitat and Ecology:||The Brown Smoothhound is a common to abundant shark where present. In the northeastern Pacific, three subpulations of this species have been described based on genetic evidence: a northern subpopulation (San Francisco), a central subpopulation (Santa Barbara, California), Santa Catalina Island, Punta Lobos, Baja California Sur, Mexico, and San Felipe, Baja California, Mexico), and a southern subpopulation (Costa Rica; Chabot et al. 2015).|
This bottom-dwelling shark is found in cold-temperate to tropical inshore and offshore waters, distributed over continental shelves (from the intertidal region to at least 200 m depth). It can be very common in enclosed, shallow muddy bays when encountered (Ebert 2003, Clarke et al. 2014). Of the three species of smoothhounds off the west coast of the United States, this species appears to be the most cold tolerant and is consistently encountered within the cold-temperate waters of northern California and Washington State (Ebert 2003). 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 (Yudin 1987, Flemming 1999, Ebert 2003). Tagging data suggest that movement patterns are fairly localized. However, data from one individual demonstrated the ability of the species to travel a distance of 155 km (96 miles) in three months (Ebert 2003). Genetic data indicates considerable gene flow throughout the central subpopulation with this subpopulation demonstrating a lack of genetic connectivity with northern and southern subpopulations (San Francisco and Costa Rica, respectively; Chabot et al. 2015). Members of the species have been observed travelling in discrete groups of similar size, sex, and age (Ebert 2003). Sex ratios have been observed to change over time in San Francisco Bay with females dominating the ratio at times (4.5:1) and males at other times (1:4; Ebert 2003).
Reproduction in this smoothhound is annual, with a gestation period of 10-12 months (Pérez-Jiménez 2006, Yudin 1987). The species is viviparous with yolk sac placenta and litter sizes range between 1-10 pups off central California and 1-21 pups within the Gulf of California (Ebert 2003, Pérez-Jiménez 2006). Size at birth is 19-30 cm total length (TL; De Wit 1975, Pérez-Jiménez 2006, Yudin and Cailliet 1990). Off San Francisco, parturition 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). Age at maturity occurs between 2 and 3 years for females and three years for males (Yudin and Cailliet 1990, Pérez-Jiménez 2006). Size at maturity is 51-66 cm total length (TL) for females and 52-66 cm TL 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). The generation length of M. henlei is 7-7.5 years (Yudin and Cailliet 1990, Chen and Yuan 2006), and the average reproductive age is estimated to be 4.7 years (Cortés 2002) with an annual rate of population increase of 1.163 (Cortés 2002) and an annual rate of natural mortality of 0.295 (Smith et al. 1998). Given that this species is a fast growing with low longevity, an early age at first maturity (Yudin and Cailliet 1990), and produces a relatively large number of pups per each year (Pérez-Jiménez 2006), it likely has a relatively high resilience to exploitation (Smith et al. 1998).
|Generation Length (years):||7-7.5|
|Use and Trade:||This species is used for its meat.|
Interest to commercial United States fisheries is likely negligible, and there is no directed fishery for this smoothhound at this time.
In the United States the majority of annual landings are a result of bycatch from fisheries targeting other species within the region, such as California halibut (Ebert 2003). Recreational anglers are the primary source of landings for the species 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. 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. 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).
Marquez-Farias (2000) stated that in the Sonora state (northeastern Gulf of California) the Brown Smoothhound was the most abundant shark species caught with gill-nets by the artisanal fishery at depths >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.
There are no species-specific conservation measures in place.
In Mexico there is a closed season for shark fishing from May to July that has been in place since 2012. This is an attempt to reduce the fishing pressure for all sharks in Mexican coastal waters.
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 (Fowler 2005). 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., Carlisle, A.B., Chabot, C.L., Vásquez, V.E. & Ebert, D.A. 2016. Mustelus henlei. The IUCN Red List of Threatened Species 2016: e.T161648A80672263.Downloaded on 22 October 2016.|
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