Register      Login
Marine and Freshwater Research Marine and Freshwater Research Society
Advances in the aquatic sciences
Shopping Cart: ( empty )
You are here: Home > Journals > MF > MF05069
RESEARCH ARTICLE
Contents Vol 56(8)

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
+ Author Affiliations
- Author Affiliations

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: debert@mlml.calstate.edu

Marine and Freshwater Research 56(8) 1089-1098 https://doi.org/10.1071/MF05069
Submitted: 8 April 2005  Accepted: 10 October 2005   Published: 22 November 2005

Abstract

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.


Acknowledgments

We would like to thank the following people for advice, assistance and discussions at various stages of this project that originally stem from the senior author’s Masters degree thesis research; K. Bates (commercial fisher), G. Cailliet, J. Bizzarro, A. Carlisle, C. Rinewalt (Pacific Shark Research Center, Moss Landing Marine Laboratories), E. Ebert (retired, California Department Fish and Game) and M. Hoberg (University of Alaska Fairbanks). Support during the terminal phase of this project was provided by NOAA/NMFS to the National Shark Research Consortium and Pacific Shark Research Center.


References

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. (1978). Sharks. 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 Africa 2, 176–177.
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. (1993). The 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 Fishes 38, 37–48.
| Crossref | GoogleScholarGoogle Scholar | Ebert D. A. (2003). ‘The Sharks, Rays and Chimaeras of California.’ (University California Press: Berkeley, CA.)

Ebert, D. A. (2005). Reproductive biology of skates, Bathyraja (Ishiyama), along the eastern Bering Sea Continental Slope. Journal of Fish Biology 66, 618–649.
| Crossref | GoogleScholarGoogle Scholar | 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. (1989). Exploitation rates of rig (Mustelus lenticulatus) around the South Island of New Zealand. New Zealand Journal of Marine and Freshwater Research 23, 239–245.
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. , and Barnhart, R. A. (1980). An annotated checklist of fishes from Humboldt Bay, California. California Fish and Game 66, 220–232.
Krebs C. J. (1999). ‘Ecological Methodology.’ 2nd edn. (Benjamin/Cummings Publishers: Menlo Park, CA.)

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.
| Crossref | GoogleScholarGoogle Scholar | 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. (1954). The biology, migration, and growth rate of the school shark, Galeorhinus australis (Macleay) (Carcharhinidae) in south-eastern Australian waters. Australian Journal of Marine and Freshwater Research 5, 353–410.
| Crossref | GoogleScholarGoogle Scholar | 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. (1979). Reproduction in the blue shark, Prionace glauca. Fishery Bulletin 77, 445–470.
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. (1975). Observations on the food habits of leopard sharks (Triakis semifasciata) and brown smoothhounds (Mustelus henlei). California Fish and Game 61, 95–103.
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. (2005). Leopard shark (Triakis semifasciata) mating activity observed off La Jolla, California. California Fish and Game 91, 128–135.
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. (1976). Food habits of the leopard shark, Triakis semifasciata, in Elkhorn Slough, Monterey Bay, California. California Fish and Game 62, 286–298.
Zar J. H. (1996). ‘Biostatistical Analysis.’ 3rd edn. (Prentice Hall: Englewood Cliffs, NJ.)