Marine and Freshwater Research Marine and Freshwater Research Society
Advances in the aquatic sciences

Reproduction, diet and habitat use of leopard sharks, Triakis semifasciata (Girard), in Humboldt Bay, California, USA

David A. Ebert A C and Thomas B. Ebert B

A Pacific Shark Research Center, Moss Landing Marine Laboratories, 8272 Moss Landing Road, Moss Landing, CA 95039, USA.

B US Abalone, PO Box 254, Davenport, CA 95017, USA.

C Corresponding author. Email:

Marine and Freshwater Research 56(8) 1089-1098
Submitted: 8 April 2005  Accepted: 10 October 2005   Published: 22 November 2005


A total of 312 female leopard sharks (Triakis semifasciata) was sampled in Humboldt Bay, California, USA, an important nursery ground for this species, during the spring month of May from 1983 to 1984 and 1985. Sexual segregation is strong as only three males were observed in the study area. Females ranged in size from 120 to 154 cm total length, and all examined were determined to be mature. Overall, 130 out of 153 females examined in early May contained term embryos. The number of embryos per female ranged from 1 to 37 with larger females tending to possess more embryos. Of the 159 individuals examined in late May, no females were found carrying embryos and most were ovulating. Diet analyses revealed that, overall, fish eggs (Atherinopsis californiensis) at 48.0%, had the highest percentage Index of Relative Importance (%IRI), followed by the cancrid crabs, Cancer antennarius (29.8%) and C. magister (11.6%). All other prey were of relatively minor importance, cumulatively representing 10.6% of the overall diet. Adults shift their diet after parturition: early May sharks fed almost exclusively on fish eggs, while crabs were more important in those examined in late May.

Extra keywords: feeding behaviour, litter size, neonates, nursery ground, sexual segregation.


Ackerman L. T. (1971). Contributions to the biology of the leopard shark, Triakis semifasciata (Girard) in Elkhorn Slough, Monterey Bay, California. Masters thesis, Sacramento State College, Sacramento, CA.

Barnhart R. A., Boyd M. J., and Pequegnat J. E. (1992). The ecology of Humboldt Bay, California: an estuarine profile. U.S. Fish and Wildlife Service Biological Report 1.

Bass A. J.1978Sharks. Ecology of the Agulhas Current region: an assessment of biological responses to environmental parameters in the South-west Indian Ocean.Transactions of the Royal Society of South Africa2176177

Berkeley S. A.Chapman C.Sogard S. M.2004Maternal age as a determinant of larval growth and survival in a marine fish, Sebastes melanops.Ecology8512581264

Branstetter S. (1990). Early life-history implications of selected carcharhinoid and lamnoid sharks of the Northwest Atlantic. In ‘Elasmobranchs as Living Resources: Advances in the Biology, Ecology, Systematics, and the Status of the Fisheries’. (Eds H. L. Pratt, Jr, S. H. Gruber and T. Taniuchi.) NOAA Technical Report 90. pp. 17–28. (National Oceanic and Atmospheric Administration: Washington, DC.)

Castro J. I.1993The shark nursery of Bulls Bay, South Carolina, with a review of the shark nurseries of the southeastern coast of the United States.Environmental Biology of Fishes383748

Cortes E.1997A critical review of methods of studying fish feeding based on analysis of stomach contents: application to elasmobrach fishes.Canadian Journal of Fisheries and Aquatic Sciences54726738doi:10.1139/CJFAS-54-3-726

Ebert D. A.1986Observations on the elasmobranch assemblage of San Francisco Bay.California Fish and Game72244249

Ebert D. A.1989Life history of the sevengill shark, Notorynchus cepedianus Peron, in two northern California Bays.California Fish and Game75102112

Ebert D. A.1991Observations on the predatory behaviour of the sevengill shark Notorynchus cepedianus.South African Journal of Marine Science11455465

Ebert D. A.2002Ontogenetic changes in the diet of the sevengill shark (Notorynchus cepedianus).Marine and Freshwater Research53517523

Ebert D. A. (2003). ‘The Sharks, Rays and Chimaeras of California.’ (University California Press: Berkeley, CA.)

Ebert D. A.2005Reproductive biology of skates, Bathyraja (Ishiyama), along the eastern Bering Sea Continental Slope.Journal of Fish Biology66618649doi:10.1111/J.0022-1112.2005.00628.X

Feder H. M., Turner C. H., and Limbaugh C. (1974). Observations on kelp fishes associated with kelp beds in southern California. California Fish and Game Fish Bulletin No. 160. (The Resources Agency Department of Fish and Game: Sacramento, CA.)

Francis M. P.1989Exploitation rates of rig (Mustelus lenticulatus) around the South Island of New Zealand.New Zealand Journal of Marine and Freshwater Research23239245

Francis M. P.Mace J. T.1980Reproductive biology of Mustelus lenticulatus from Kaikoura and Nelson.New Zealand Journal of Marine and Freshwater Research14303311

Goosen A. J. J. (1997). The reproduction, age and growth of the spotted gully shark, Triakis megalopterus, off the Eastern Cape coast. Masters thesis, University of Port Elizabeth, Port Elizabeth, South Africa.

Gotshall D. W.Allen G. N.Barnhart R. A.1980An annotated checklist of fishes from Humboldt Bay, California.California Fish and Game66220232

Gray A. E.Mulligan T. J.Hannah R. W.1997Food habits, occurrence, and population structure of the bat ray, Myliobatis californica, in Humboldt Bay, California.Environmental Biology of Fishes49227238

Gruber S. H.Nelson D. R.Morrissey J. F.1988Patterns of activity and space utilization of lemon sharks, Negaprion brevirostris, in a shallow Bahamian lagoon.Bulletin of Marine Science436176

Herald E. S.Ripley W. E.1951The relative abundance of sharks and bat stingrays in San Francisco Bay.California Fish and Game37315329

Herald E. S.Schneebeli W.Green N.Innes K.1960Catch records for seventeen shark derbies held at Elkhorn Slough, Monterey Bay, California.California Fish and Game465967

Heupel M. R.Hueter R. E.2002Importance of prey density in relation to the movement patterns of juvenile blacktip sharks (Carcharhinus limbatus) within a coastal nursery area.Marine and Freshwater Research53543550

Krebs C. J. (1999). ‘Ecological Methodology.’ 2nd edn. (Benjamin/Cummings Publishers: Menlo Park, CA.)

Kusher D. I.Smith S. E.Cailliet G. M.1992Validated age and growth of the leopard shark, Triakis semifasciata, with comments on reproduction.Environmental Biology of Fishes35187203doi:10.1007/BF00002193

Langton R. W.1982Diet overlap between Atlantic cod, Gadus morhua, silver hake, Merluccius bilinearis, and fifteen other northwest Atlantic finfish.Fishery Bulletin80745759

Miller D. J., and Lea R. N. (1972). Guide to the coastal marine fishes of California. California Fish and Game Fish Bulletin No. 157. (The Resources Agency, Department of Fish and Game: Sacramento, CA.)

Olsen A. M.1954The biology, migration, and growth rate of the school shark, Galeorhinus australis (Macleay) (Carcharhinidae) in south-eastern Australian waters.Australian Journal of Marine and Freshwater Research5353410

Palumbi S. R.2004Why mothers matter.Nature430621622doi:10.1038/430621A

Peres M. B.Vooren C. M.1991Sexual development, reproductive cycle, and fecundity of the school shark Galeorhinus galeus off southern Brazil.Fishery Bulletin89655667

Pinkas L., Oliphant M. S., and Iverson I. L. K. (1971). Food habits of the albacore, bluefin tuna, and bonito in California waters. California Fish and Game Fish Bulletin No. 152. (The Resources Agency, Department of Fish and Game: Sacramento, CA.)

Pratt H. L.1979Reproduction in the blue shark, Prionace glauca.Fishery Bulletin77445470

Ripley W. E. (1946). The biology of the soupfin Galeorhinus zyopterus and biochemical studies of the liver. California Fish and Game Fish Bulletin No. 64. (The Resources Agency, Department of Fish and Game: Sacramento, CA.)

Russo R. A.1975Observations on the food habits of leopard sharks (Triakis semifasciata) and brown smoothhounds (Mustelus henlei).California Fish and Game6195103

Simpfendorfer C. A.Milward N. E.1993Utilisation of a tropical bay as a nursery area by sharks of the families Carcharhinidae and Sphyrnidae.Environmental Biology of Fishes37337345

Smale M. J.Compagno L. J. V.1997Life history and diet of two southern African smoothhound sharks, Mustelus mustelus (Linnaeus, 1758) and Mustelus palumbes Smith, 1957 (Pisces: Triakidae).South African Journal of Marine Science18229248

Smale M. J.Goosen A. J. J.1999Reproduction and feeding of spotted gully shark, Triakis megalopterus, off the Eastern Cape, South Africa.Fishery Bulletin97987998

Smith S. E. (2001). Leopard shark. In ‘California’s Living Marine Resources: A Status Report’. (Eds W. S. Leet, C. M. Dewees, R. Klingbiel and E. J. Larson.) pp. 252–254. (The Resources Agency, California Department Fish and Game: Sacramento, CA.)

Smith S. E.2005Leopard shark (Triakis semifasciata) mating activity observed off La Jolla, California.California Fish and Game91128135

Smith S. E.Abramson N. J.1990Leopard shark Triakis semifasciata distribution, mortality rate, yield, and stock replenishment estimates based on a tagging study in San Francisco Bay.Fishery Bulletin88371381

Snelson F. F.Mulligan T. J.Williams S. E.1984Food habits, occurrence, and population structure of the bull shark, Carcharhinus leucas, in Florida coastal lagoons.Bulletin of Marine Science347180

Springer S.1960Natural history of the sandbar shark, Eulamia milberti.Fishery Bulletin of the U.S. Fish and Wildlife Service61138

Springer S. (1967). Social organization of shark populations. In ‘Sharks, Skates, and Rays’. (Eds P. W. Gilbert, R. F. Mathewson and D. P. Rall.) pp. 149–174. (Johns Hopkins Press: Baltimore, MD.)

Talent L. G.1976Food habits of the leopard shark, Triakis semifasciata, in Elkhorn Slough, Monterey Bay, California.California Fish and Game62286298

Talent L. G.1985The occurrence, seasonal distribution, and reproductive condition of elasmobranch fishes in Elkhorn Slough, California.California Fish and Game71210219

Wourms J. P.Demski L. S.1993The reproduction and development of sharks, skates, rays and ratfishes: introduction, history, overview, and future prospects.Environmental Biology of Fishes38721

Zar J. H. (1996). ‘Biostatistical Analysis.’ 3rd edn. (Prentice Hall: Englewood Cliffs, NJ.)

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