Triakis semifasciata, Leopard Shark - IUCN Red List

The IUCN Red List of Threatened Species™ ISSN 2307-8235 (online) IUCN 2008: T39363A80672743

Triakis semifasciata, Leopard Shark Assessment by: Carlisle, A.B., Smith, S.E., Launer, A.L. & White, C.F.

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Citation: Carlisle, A.B., Smith, S.E., Launer, A.L. & White, C.F. 2015. Triakis semifasciata. The IUCN Red List of Threatened Species 2015: e.T39363A80672743. http://dx.doi.org/10.2305/IUCN.UK.2015-4.RLTS.T39363A80672743.en Copyright: © 2015 International Union for Conservation of Nature and Natural Resources Reproduction of this publication for educational or other non-commercial purposes is authorized without prior written permission from the copyright holder provided the source is fully acknowledged. Reproduction of this publication for resale, reposting or other commercial purposes is prohibited without prior written permission from the copyright holder. For further details see Terms of Use. The IUCN Red List of Threatened Species™ is produced and managed by the IUCN Global Species Programme, the IUCN Species Survival Commission (SSC) and The IUCN Red List Partnership. The IUCN Red List Partners are: BirdLife International; Botanic Gardens Conservation International; Conservation International; Microsoft; NatureServe; Royal Botanic Gardens, Kew; Sapienza University of Rome; Texas A&M University; Wildscreen; and Zoological Society of London. If you see any errors or have any questions or suggestions on what is shown in this document, please provide us with feedback so that we can correct or extend the information provided.

THE IUCN RED LIST OF THREATENED SPECIES™

Taxonomy Kingdom

Phylum

Class

Order

Family

Animalia

Chordata

Chondrichthyes

Carcharhiniformes

Triakidae

Taxon Name: Triakis semifasciata Girard, 1855 Synonym(s): • Triakis semifasciatum Girard, 1855

Common Name(s): • English:

Leopard Shark

Taxonomic Source(s): Eschmeyer, W.N. and Fricke, R. (eds). 2015. Catalog of Fishes: genera, species, references. Updated 1 October 2015. Available at: http://researcharchive.calacademy.org/research/ichthyology/catalog/fishcatmain.asp. (Accessed: 1 October 2015).

Assessment Information Red List Category & Criteria:

Least Concern ver 3.1

Year Published:

2015

Date Assessed:

December 18, 2014

Justification: Leopard Shark (Triakis semifasciata) is one of the most common nearshore sharks along the Pacific coast of North America, ranging from Washington to Mazatlan, Mexico, including the Gulf of California. They appear to exhibit limited long distance movement, and as a result it is thought that the population consists of three regional population clusters in northern California, southern California and Mexico with limited genetic exchange. In California, where nearly all of the U.S. harvest occurs, the Leopard Shark is taken primarily by recreational anglers, although it is also caught incidentally in commercial fisheries. The species has also been harvested for the cold-water aquarium trade and has been highly prized for its distinctive markings and hardiness. Due to its rather limited geographical range and limited exchange among regional stocks, resident stocks near large population centres may be particularly vulnerable to heavy localized fishing pressure. However, this species does not appear to be at risk judging by the combined landings in relation to previously calculated estimates of fishing mortality and exploitation rates. Additionally, current conservation and regulatory actions enacted by the California Department of Fish and Wildlife appear to have reduced these rates and have contributed significantly toward protecting this species from excessive harvesting in recent years and there is evidence that the leopard shark population has been increasing as a result of these management actions.

© The IUCN Red List of Threatened Species: Triakis semifasciata – published in 2015. http://dx.doi.org/10.2305/IUCN.UK.2015-4.RLTS.T39363A80672743.en

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Little is known of the biology, historical population abundance and full extent of harvest of this species in Mexican waters, but it is estimated to be less than one percent of the Pacific Ocean catch off Baja California and rarely caught in the Gulf of California. As a result of the success of the conservation measures taken in the U.S. and the lack of a significant fishery in Mexican waters, this species is assessed as Least Concern. However, due to the fact that this species is endemic to this region, is subjected to recreational fishing and bycatch pressures (albeit regulated in the U.S.), is susceptible to overfishing due to its life history characteristics (slow growing, long lived, late maturing, low productivity), and is impacted by habitat loss and degradation, it is important to continue managing and monitoring the species to ensure the health of the species.

Previously Published Red List Assessments 2009 – Least Concern (LC) – http://dx.doi.org/10.2305/IUCN.UK.2009-2.RLTS.T39363A10216614.en 2000 – Lower Risk/conservation dependent (LR/cd)

Geographic Range Range Description: This is one of the most common nearshore sharks along the west coast of North America (Ebert 2003). In U.S. waters, the leopard shark is most abundant along the coast of California. Leopard Shark is endemic to the Northeast Pacific Ocean, ranging from Samish Bay, Washington to Mazatlan, Mexico, including the Gulf of California. In Oregon waters, Emmett et al. (1991) record this species only from Coos Bay, where it is listed as ‘rare’. They are commonly found in bays and estuaries, and have been reported from Coos Bay, Willapa Bay, Humboldt Bay, Tomales Bay, Bodega Bay, Bolinas Lagoon, San Francisco Bay, Elkhorn Slough, Morro Bay, San Pedro Bay, Alamitos Bay, Anaheim Bay, Newport Bay, Mission Bay, Bolsa Chica Lagoon, and San Diego Bay (Bane and Bane 1971, Emmet et al. 1991, Ebert 2003, Farrer 2009, Farrugia et al. 2014). They are also found along the open coast (Nosal et al. 2013a, 2014) and around offshore islands, such as the Channel Islands in southern California (Manley 1995, Ebert, 2003, Hight and Lowe 2007).

Country Occurrence: Native: Mexico (Baja California, Baja California Sur, Sinaloa, Sonora); United States (California, Oregon)

FAO Marine Fishing Areas: Native: Pacific - northeast, Pacific - eastern central


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Distribution Map


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Population It is thought that the Leopard Shark population consists of regional stocks with limited connectivity (Smith and Abramson 1990, Lewallen et al. 2007). Lewallen et al. (2007) reported that there were seven subpopulations between Humboldt Bay and San Diego, with the Humboldt Bay population of leopard sharks being the most genetically distinct from the rest of the more southerly distributed populations. They also found some evidence of natal philopatry, which they suggest may be in part what drives the observed genetic structure. More recently, a genetic study of Leopard Shark from sample locations ranging from northern California to Mexico showed that distinct populations exist in northern California, southern California and Mexico (Barker et al. 2015). Within Mexican waters, the Pacific coast and Gulf of California stocks may be distinct populations (Smith 2001). Current Population Trend: Unknown

Habitat and Ecology (see Appendix for additional information) Leopard Shark is a temperate shark of both inshore and offshore continental littoral waters, generally found on or near the bottom in shallow water from the intertidal to 20 m depth, although they have been found as deep as 156 m (Ebert 2003, Love 2011). This species is generally found over soft bottom habitats and around rocky reefs and kelp forests (Ebert 2003). Leopard sharks are relatively eurythermal and euryhaline species, but their distribution is known to be influenced by temperature, salinity, and dissolved oxygen levels (Hopkins and Cech 2003, Hight and Lowe 2007, Carlisle and Starr 2009, Dowd et al. 2010, Nosal et al. 2014). In their survey of Pacific coast estuaries, Emmet et al. (1991) reported that Leopard Shark of all age classes are commonly found in bays and estuaries between San Pedro Bay in Southern California and Humboldt Bay in Northern California, although they are particularly abundant in Elkhorn Slough, San Francisco Bay, Tomales Bay and Humboldt Bay. In southern California, they are known to form large aggregations in San Diego and the Channel Islands (Manley 1995, Hight and Lowe 2007, Nosal et al. 2013a, 2014). Leopard Shark are seasonally abundant in bays and estuaries (such as Elkhorn Slough, Humboldt Bay, Tomales Bay, Bodega Bay, and San Francisco Bay) during the spring and summer, then during the winter they often move out of the bays to coastal waters as salinity and temperature decrease (Hopkins and Cech 2003, Carlisle and Starr 2009). In San Francisco Bay the population is mainly resident but about 10% move out of the bay in fall and winter (Smith and Abramson 1990). Leopard shark movements in bays and estuaries are strongly influenced by the tidal cycle. Leopard sharks will swim with tidal currents to reduce energetic costs associated with swimming as well as to facilitate foraging over a larger area (Ackerman et al. 2000, Carlisle et al. 2010). During incoming tides they move into shallow mudflats to forage and retreat to deeper water as the tide goes out (Ackerman et al. 2000, Carlisle and Starr 2009, Carlisle and Starr 2010). In exposed coastlines, tides have been shown to drive leopard shark movement between sand flats and rocky reefs (Nosal et al. 2013a). Leopard sharks have been reported to be more active at night (Manley 1995, Ackerman et al. 2000, Carlisle et al. 2010, Nosal et al. 2013a) as their rates of movement are generally higher at night. Manley (1995) reported that acoustically tagged leopard sharks at Santa Catalina Island, California, were more active at night, possibly related to foraging. Leopard Shark appear to exhibit limited long distance movements, although they are capable of moving relatively large distances rapidly. One shark acoustically tagged at Catalina Island was detected seven days later along the mainland coast, a movement of approximately 105 km through deep water, after


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which it returned to Catalina Island (Hight and Lowe 2007). There have been several instances of sharks travelling ~100 km distance between Monterey Bay and San Francisco Bay and one shark tagged in San Francisco Bay was recaptured ~600 km away in Santa Monica Bay in southern California 10 years later, but in general, large scale movements appear to be limited (Smith 2001). This is supported by studies that have demonstrated that there is limited genetic exchange between Leopard Shark along different parts of the coast (Lewallen et al. 2007, Barker et al. 2015) and studies that have shown a high degree of site fidelity and potential natal philopatry, with many individuals consistently returning to particular locations (Lewallen et al. 2007, Carlisle and Starr 2009, Nosal et al. 2014, Barker et al. 2015). Leopard sharks are viviparous, without a yolk sac placenta, and the female produces from 7 to 36 offspring in an annual reproductive cycle. Gestation time is 10-12 months, and size at birth is 17 to 25 cm total length (TL; Ackerman 1971, Kusher et al. 1992, Smith 2001). Age at maturity for females is between 10 and 15 years and 105 to 135 cm TL. Males mature between 7 and 13 years and at 100 to 105 cm TL. The maximum size is 198 cm TL with reports of sharks up to 213 cm TL (Miller and Lea 1972, Feder et al. 1974, Kusher et al. 1992, Smith et al. 2003). Maximum age is at least 25 years, but is estimated to be about 30 years with an estimated generation time of 18.5 years (Cortes 2002). Pregnant females are believed to exhibit behavioural thermoregulation and aggregate in shallow warm habitats, likely to accelerate embryonic development (Hight and Lowe 2007, Nosal et al. 2013a, 2014). Bays and estuaries appear to be important nursery areas, particularly in central and northern California. Reported nursery areas include Humboldt Bay, San Francisco Bay, Tomales Bay, Bodega Bay, Elkhorn Slough, San Diego Bay and Catalina Harbor (Eigenmann 1891, Bane and Bane 1971, Talent 1985, Smith 2001, Ebert 2003, Carlisle et al. 2007), although Emmet et al. (1991) also reported the presence of juveniles in Morro Bay, Santa Monica Bay, and San Pedro Bay. In central and northern California, parturition appears to occur from March through September, with a peak in April and May (Ackerman 1971, Talent 1985, Smith and Abramson 1990, Ebert and Ebert 2005). In southern California pupping is believed to occur around May and June, although it has been reported to occur as late as September in San Diego Bay (Eigenmann 1891, Smith 2005). Mating is believed to occur shortly after pupping (Ackerman 1971, Talent 1985, Ebert 2003) and has only been observed once in the wild, in the shallow surf zone in La Jolla (Smith 2005). Females may mate with multiple males with as many as 36% of litters having multiple paternity (Nosal et al. 2013b). Females generally give birth in shallow protected habitats, often over sand or mudflats (Love 2011). In central and northern California, neonates and juveniles are often found in more sheltered, shallow, inshore areas such as bays, mudflats, and tidal creeks (Barry and Cailliet 1983, Carlisle and Starr 2009). In Humboldt and San Francisco Bay, females have been observed releasing their young in beds of eel grass (Ebert 2003, Ebert and Ebert 2005). In southern California pupping and nursery areas are generally thought to be in the surf zone and sheltered coves of more open coast habitats (Smith 2001, Ebert 2003, Hight and Lowe 2007, Nosal et al. 2013). Leopard sharks have been observed giving birth in Catalina Harbor over sandy bottom in water as shallow as 1 m, with pups found in water only 0.3 m deep (Smith 2001).

Systems: Marine

Use and Trade This species is collected and traded for aquariums. © The IUCN Red List of Threatened Species: Triakis semifasciata – published in 2015. http://dx.doi.org/10.2305/IUCN.UK.2015-4.RLTS.T39363A80672743.en

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Threats (see Appendix for additional information) Leopard Sharks appear to be primarily caught in Californian waters. The commercial and recreational catch of leopard sharks in the extreme northerly part of its range in Oregon is thought to be negligible (Emmett et al. 1991, Pacific Fisheries Information Network (PacFIN), Recreational Fisheries Information Network (RecFIN)). In California, where nearly all of the U.S. harvest occurs, the leopard shark is taken primarily by recreational anglers. The recreational leopard shark catch is much more extensive than the commercial catch for this species. Leopard sharks have been recreationally harvested by angling with baited hooks from piers, jetties, beaches, banks and skiffs, bow fishing in shallow waters, and spearfishing by divers. Estimated recreational landings in California between 1980 and 1995, for years when data were collected, averaged over 138 metric tons (mt) annually. After a peak in 1987 of around 546 mt, recreational landings declined and from the mid 1990’s to 2006 remained relatively lower and stable at around 46 mt (PacFIN, Smith and Horeczko 2006). Since 2006, recreational catch has decreased from prior levels (RecFIN). Commercially, leopard sharks are taken incidentally in gillnet, longline and trawl fisheries although there is a small targeted hook-and-line fishery in San Francisco Bay (Smith and Horeczko 2006). A problem exists in accurately judging the extent of the commercial harvest because an unknown portion of the commercial catch may be landed under the general category ‘shark, unspecified’ and different species are often marketed under the generic name “shark.” California commercial landings specifically reported under the ‘Leopard Shark' category are relatively minor, and have ranged from 4.2 mt in 1958 to a high of 46 mt in 1983. Catches declined after 1983 and from the mid 1990’s to 2007 remained relatively low and stable, at around 11.4 mt. Landings dropped after 2008 and have remained low at around 2.3 mt per year since (http://pacfin.psmfc.org). Curtailment of inshore gillnetting probably contributed greatly to the decline in California landings. The species has also been harvested for the cold-water aquarium trade and is highly prized for its distinctive markings and hardiness (Smith and Horeczko 2006). Loss and alteration of habitat, especially in coastal bays and estuaries, is of great concern for this species, given the importance of these areas for foraging and as nursery sites (Carlisle and Starr 2009). Water quality in bays and estuaries is of potential concern as well. For example, Elkhorn Slough, an important foraging and nursery area for this species, has experienced severe nutrient loading from surrounding agricultural areas, resulting in eutrophication and hypoxic conditions, which impact habitat and prey availability (Hughes et al. 2013). This is a potential problem as there is evidence that dissolved oxygen levels may influence habitat availability of this species (Carlisle and Starr 2009). Leopard sharks have also been shown to have significant concentrations of contaminants in their tissues, but the impact of this on their fitness remains unknown (Schaffer et al. 2006, Carlisle et al. 2007). Resident stocks near large population centres may be particularly vulnerable to heavy localized fishing pressure due to the limited exchange among regional stocks (Smith and Abramson 1990, Lewallen et al. 2007, Barker et al. 2015). Even though the commercial catch may be under-estimated because of reporting problems, this species does not appear to be at risk judging by the combined landings in relation to previously calculated estimates of fishing mortality (mean F=0.084) and exploitation rates (mean E=0.075; Smith and Abramson 1990). Additionally, current fisheries management measures appear to have reduced these rates.


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Poaching of pups for the aquarium trade has been a significant problem. In 2006, several individuals were arrested for illegally harvesting Leopard Shark pups for the aquarium trade. Investigators estimated that between 20,000 to 25,000 pups were poached from San Francisco Bay and 30,000 to 33,000 pups were poached from southern California between 1992 and 2003. This level of harvest is quite large when compared to recreational and commercial fishery Leopard Shark landings, with potentially important ramifications to Leopard Shark populations (Smith and Horeczko 2006). Little is known of the biology and full extent of harvest of this species in Mexican waters, but it is estimated that less than one percent of the catch off the Pacific coast of Baja California is comprised of this species (Cartamil et al. 2011) and most of the shark catch in the central Gulf of California fishery is comprised of other, larger species (e.g., Alopias and Carcharhinus spp.; Bizzarro et al. 2009). However, the historical abundance of Leopard Sharks in this region is also unknown.

Conservation Actions In 1990, tagging and other life history data were used to estimate fishing mortality, yield, and stock replenishment rates to determine the degree of vulnerability to fishing pressure for Leopard Shark (Smith and Abramson 1990). Researchers indicated that, given the amount of fishing pressure exerted in the 1980s and that leopard sharks are more susceptible to overexploitation than previously thought, some measure of protection was necessary to assure replenishment of the population (Cailliet 1992, Au and Smith 1997), especially considering that they are caught in both commercial and recreational fisheries and considered to be a desirable food fish. The leopard shark is one of the many species that has been considered, but is not now actively regulated, under the Pacific Fishery Management Council’s Groundfish Management Plan. Regulatory actions enacted by the California Department of Fish and Wildlife (CDFW) have contributed significantly toward protecting this species. In 1991, efforts increased to protect the leopard shark in California, and late that year California established new sport fishing regulations which took effect on 1 January 1992, establishing a 36 inch (91 cm) minimum size and a daily bag limit of three fish. The recreational fishing sector not only strongly supported the move, but also did much to promote it. Effective 1 January 1993, an 18 inch (45.7 cm) minimum size limit was extended to the commercial fishery for Leopard Shark and all sharks and rays, to prevent over-harvesting for the aquarium trade. Additionally, California has general restrictions on usage of certain types of commercial gear (in particular gillnets) in the near shore zone, which offers a good degree of protection for the Leopard Shark. CDFW’s imposition of recreational and commercial fishing regulations appears to have halted the increase, if not reduced, total fishing mortality over the past decade (Smith et al. 1998). Indeed there is evidence that Leopard Shark have rebounded since regulations were implemented (Pondella and Allen 2008).

Credits Assessor(s):

Carlisle, A.B., Smith, S.E., Launer, A.L. & White, C.F.

Reviewer(s):

Nosal, A.P. & Chabot, C.L.


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Contributor(s):

Machura, B.

Facilitators(s) and Compiler(s):

Lawson, J., Walls, R.H.L., Ebert, D.A. & Dulvy, N.K.


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Bibliography Ackerman, L.T. 1971. Contributions to the biology of the leopard shark, Triakis semifasciata (Girard) in Elkhorn Slough, Monterey Bay, California. M.A. thesis. Sacramento State College. Ackerman, L.T., Kondraieff, M.C. Matern, S.A. and Cech, J.J. 2000. Tidal influence on spatial dynamics of leopard sharks, Triakis semifasciata, in Tomales Bay California. Environmental Biology of Fishes 58: 3343. Au, D.W. and Smith, S.E. 1997. A demographic method with population density compensation for estimating productivity and yield per recruit of the leopard shark (Triakis semifasciata). Canadian Journal of Fisheries and Aquatic Science 54: 415-420. Bane, G.W. and Bane, A.W. 1971. Bay fishes of northern California. Mariscos Publications, Hampton Bays, New York. Barker, A.M., Nosal, A.P., Lewallen, E.A. and Burton, R.S. 2015. Genetic structure of leopard shark (Triakis semifasciata) populations along the Pacific coast of North America. Journal of Experimental Marine Biology and Ecology 472: 151-157. Barry, J.P. and Cailliet, G.M. 1983. The utilization of shallow marsh habitats by commercially important fishes in Elkhorn Slough, California. Cal-Neva Wildlife Transactions 1981: 38-47. Barry, J.P., Yoklavich, M.M., Cailliet, G.M., Ambrose, D.A., and Antrim, B.S. 1996. Trophic ecology of the dominant fishes in Elkhorn Slough, California, 1974-1980. Estuaries 19: 115-138. Bizzarro, J.J., Smith, W.D., Hueter, R.E., and Villavicencio-Garayzar, C.J. 2009. Activities and catch composition of artisanal elasmobranch fishing sites on the eastern coast of Baja California Sur, Mexico. Bulletin of the Southern California Academy of Sciences 108: 137-151. Cailliet, G.M. 1992. Demography of the central California population of the leopard shark (Triakis semifasciata). Australian Journal of Marine and Freshwater Research 43: 183-193. Carlisle, A.B. and Starr, R.M. 2009. Habitat use, residency, and seasonal distribution of female leopard sharks Triakis semifasciata in Elkhorn Slough, California. Marine Ecology Progress Series 380(213-228). Carlisle, A.B. and Starr, R.M. 2010. Tidal movements of female leopard sharks (Triakis semifasciata) in Elkhorn Slough, California. Environmental Biology of Fishes 89: 31-45. Carlisle, A.B., King, A., Cailliet, G.M., and Brennan, J.S. 2007. Long-term trends in catch composition from elasmobranch derbies in Elkhorn Slough, California. Marine Fisheries Review 69: 25-45. Cortes, E. 2002. Incorporating uncertainty into demographic modeling: application to shark populations and their conservation. Conservation Biology 16: 1048-1062. DeWitt, S.W. 1955. A record of an attack by a leopard shark (Triakis semifasciata Girard). California Department of Fish and Game 41(4): 348. Dowd, W.W., Harris, B.N., Cech, J.J., Jr., and Kultz, D. 2010. Proteomic and physiological responses of leopard sharks (Triakis semifasciata) to salinity change. . Journal of Experimental Biology 213: 210-224. Ebert, D.A. 2003. Sharks, Rays and Chimaeras of California. University of California Press, Berkley. Ebert, D.A. and Ebert, T.B. 2005. Reproduction, diet and habitat use of leopard sharks, Triakis semifasciata (Girard), in Humboldt Bay, California, USA. Marine and Freshwater Research 56: 10891098.


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Eigenmann, C.H. 1891. The spawning season of San Diego fishes. Emmett, R.L., Hinton, S.A. Stone, S.L. and Monaco, M.E. 1991. Distribution and abundance of fishes and invertebrates in west coast estuaries, Volume II: Species life history summaries. NOAA/NOS Strategic Environmental Assessments Division, Rockville, Maryland. Farrer, D.A. 2009. Northern range extension of the leopard shark, Triakis semifasciata. California Fish and Game 95: 62-64. Farrugia, T.J.,. Espinoza, M., and Lowe, C.G. 2014. The fish community of a newly restored southern California estuary: ecological perspective 3 years after restoration. Environmental Biology of Fishes 97: 1129-1147. Feder, H.M., Turner, C.H. and Limbaugh, C. 1974. Observations on fishes associated with kelp beds in southern California. California Fish and Game Fish Bulletin 160(160): 1-44. Girard, C.F. 1854. Characteristics of some cartilaginous fishes of the Pacific coast of North America. Proceedings of the Academy of Natural Science of Philadelphia 7(6): 196-197. Hight, B.V. and Lowe, C.G. 2007. Elevated body temperatures of adult female l eopard sharks, Triakis semifasciata, while aggregating in shallow nearshore embayments: Evidence for behavioral thermoregulation? Journal of Experimental Marine Biology and Ecology 352: 114-128. Hopkins, T.E. 1993. The physiological ecology of bat rays, Myliobatis californica, in Tomales Bay, California. Ph.D. Thesis, University of California. Hopkins, T.E. and Cech,J.J., Jr. 2003. The influence of environmental variables on the distribution and abundance of three elasmobranchs in Tomales Bay, California. . Environmental Biology of Fishes 66: 279-291. Hughes, B.B., Eby, R., Van Dyke, E., Tinker, M.T., Marks, C.I., Johnson, K.S., and Wasson, K. 2013. Recovery of a top predator mediates negative eutrophic effects on seagrass. Proceedings of the National Academy of Sciences 110(38): 15313-15318. Hughes B.B., Haskins J.C., Wasson K., and Watson E. 2011. Identifying factors that influence the expression of eutrophication in a central California estuary. Marine Ecology Progress Series 439: 31-43. IUCN. 2015. The IUCN Red List of Threatened Species. Version 2015-4. Available at: www.iucnredlist.org. (Accessed: 19 November 2015). Kao, J.S. 2000. Diet, daily ration and gastric evacuation of the leopard shark (Triakis semifasciata). M.S. thesis. California State University, Hayward. Kusher, D.I., Smith, S.E. and Cailliet, G.M. 1992. Validated age and growth of the leopard shark, Triakis semifasciata, with comments on reproduction. Environmental Biology of Fishes 35: 187-203. Lewallen, E.A., Anderson, T.W., and Bohonak, A.J. 2007. Genetic structure of leopard shark (Triakis semifasciata) populations in California waters. Marine Biology 152(599-609). Manley, J.F. 1995. Diel movement patterns of leopard sharks, Triakis semifasciata, at Santa Catalina Island, California. M.S. thesis. California State University Long Beach. Miller, D.J. and Lea, R.N. 1972. Guide to the coastal marine fishes of California. California Department of Fish and Game, California. Nosal, A.P., Caillat, A., Kisfaludy, E.K., Royer, M.A., and Wegner, N.C. 2014. Aggregation behavior and seasonal philopatry in male and female leopard sharks Triakis semifasciata along the open coast of


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southern California, USA. Marine Ecology Progress Series 449: 157-175. Nosal, A.P., Cartamil, D.P., Long, J.W., Luhrmann, M., Wegner, N.C., and Graham, J.B. 2013. Demography and movement patterns of leopard sharks (Triakis semifasciata) aggregating near the head of a submarine canyon along the open coast of southern California, USA. Environmental Biology of Fishes 96: 865-878. Nosal, A.P., Lewallen, E.A., and Burton, R.S. 2013. Multiple paternity in leopard shark (Triakis semifasciata) litters sampled from a predominantly female aggregation in La Jolla, California, USA. Journal of Experimental Marine Biology and Ecology 446: 110-114. Pondella, D.J. and Allen, L.G. 2008. The decline and recovery of four predatory fishes from the Southern California Bight. Marine Biology 154: 307-313. Russo, R.A. 1975. Observations on the food habits of leopard sharks (Triakis semifasciata) and brown smoothhounds (Mustelus henlei). California Department of Fish Game, California. Smith, S.E. 1992. Leopard shark. In: W.S. Leet, C.M. Dewees, and C.W. Haugen (eds), California's living marine resources and their utilization., pp. 48–49. California Sea Grant Extension Publication UCSGEP92-12, Davis, CA, USA. Smith, S.E. 2005. Leopard shark mating observed off La Jolla, California. California Fish and Game 91: 128-135. Smith, S.E. and Abramson, N. 1990. Leopard shark Triakis semifasciata distribution, mortality rate, yield, and stock replenishment estimates based on a tagging study in San Fracisco Bay. Fishery Bulletin 88(2): 371-381. Smith, S.E. and Horeczko, M. 2006. Leopard sharks. California’s Living Marine Resources: A Status Report through 2006. California Department of Fish and Game Marine Region. Smith, S.E., Au, D.W. and Show, C. 1998. Intrinsic rebound potentials of 26 species of Pacific sharks. Marine and Freshwater Research 49(7): 663-678. Smith, S.E., Mitchell, R.A. and Fuller, D. 2003. Age-validation of a leopard shark (Triakis semifasciata) recaptured after 20 years. Fish Bulletin 101: 194-198. Talent, L.G. 1976. Food habits of the leopard shark, Triakis semifasciata in Elkhorn Slough, Monterey Bay, California. California Department of Fish Game Fish Bulletin 62(4): 286-298. Talent, L.G. 1985. The occurrence, seasonal distribution, and reproductive condition of elasmoranch fishes in Elkhorn Slough, California. California Fish and Game 71(4): 210-219. Webber, J.D. and Cech, J.J. 1998. Nondestructive diet analysis of the leopard shark from two sites in Tomales Bay, California. California Fish and Game 84: 18-24.

Citation Carlisle, A.B., Smith, S.E., Launer, A.L. & White, C.F. 2015. Triakis semifasciata. The IUCN Red List of Threatened Species 2015: e.T39363A80672743. http://dx.doi.org/10.2305/IUCN.UK.20154.RLTS.T39363A80672743.en

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Appendix Habitats (http://www.iucnredlist.org/technical-documents/classification-schemes) Habitat

Season

Suitability

Major Importance?

9. Marine Neritic -> 9.2. Marine Neritic - Subtidal Rock and Rocky Reefs

-

Suitable

-

9. Marine Neritic -> 9.3. Marine Neritic - Subtidal Loose Rock/pebble/gravel

-

Suitable

-

9. Marine Neritic -> 9.4. Marine Neritic - Subtidal Sandy

-

Suitable

-

9. Marine Neritic -> 9.5. Marine Neritic - Subtidal Sandy-Mud

-

Suitable

-

9. Marine Neritic -> 9.6. Marine Neritic - Subtidal Muddy

-

Suitable

-

9. Marine Neritic -> 9.7. Marine Neritic - Macroalgal/Kelp

-

Suitable

-

Threats (http://www.iucnredlist.org/technical-documents/classification-schemes) Threat

Timing

Scope

Severity

Impact Score

5. Biological resource use -> 5.4. Fishing & harvesting aquatic resources -> 5.4.1. Intentional use: (subsistence/small scale)

Ongoing

Unknown

Unknown

Unknown

Stresses:

2. Species Stresses -> 2.1. Species mortality 2. Species Stresses -> 2.2. Species disturbance

Ongoing

Unknown

Stresses:


Ongoing

Whole (>90%)

Stresses:


Ongoing

Whole (>90%)

Stresses:


5. Biological resource use -> 5.4. Fishing & harvesting aquatic resources -> 5.4.2. Intentional use: (large scale)

5. Biological resource use -> 5.4. Fishing & harvesting aquatic resources -> 5.4.3. Unintentional effects: (subsistence/small scale)

5. Biological resource use -> 5.4. Fishing & harvesting aquatic resources -> 5.4.4. Unintentional effects: (large scale)

Unknown

Unknown

Unknown

Unknown

Unknown

Unknown

Research Needed (http://www.iucnredlist.org/technical-documents/classification-schemes)


13

Research Needed 1. Research -> 1.2. Population size, distribution & trends 1. Research -> 1.3. Life history & ecology 3. Monitoring -> 3.1. Population trends

Additional Data Fields Distribution Lower depth limit (m): 91 Upper depth limit (m): 1

Population Population severely fragmented: No

Habitats and Ecology Generation Length (years): 25


14

The IUCN Red List Partnership

The IUCN Red List of Threatened Species™ is produced and managed by the IUCN Global Species Programme, the IUCN Species Survival Commission (SSC) and The IUCN Red List Partnership. The IUCN Red List Partners are: BirdLife International; Botanic Gardens Conservation International; Conservation International; Microsoft; NatureServe; Royal Botanic Gardens, Kew; Sapienza University of Rome; Texas A&M University; Wildscreen; and Zoological Society of London.

THE IUCN RED LIST OF THREATENED SPECIES™