Reproductive biology of the scalloped hammerhead shark Sphyrna lewini (Chondrichthyes: Sphyrnidae) off south-west Mexico
Marcela Bejarano-Álvarez, Felipe Galván-Magaña and Rosa Isabel Ochoa-Báez
aqua, International Journal of Ichthyology, pp. 11-22, Volume 17, Issue 1 – 15 January 2011
The scalloped hammerhead shark Sphyrna lewini is the most important species in the artisanal shark fishery in the Gulf of Tehuantepec, Mexico. Knowledge about the reproductive biology of this species in the area is nonexistent, despite its being listed worldwide as endangered by the IUCN. To determine the basic reproductive biology of this shark would give important data for management or conservation plans for this species in Mexico. Samples were collected of 991 hammerhead sharks (342 females and 649 males), including juveniles (45 to 160 cm TL) and adults (170 to 288 cm TL), from September 2004 to June 2006. The sex ratio was 1F: 2M. The scalloped hammerhead was present year round in the study area with the greatest catch from May to July, the season when pregnant females were present. The females reached sexual maturity at 220 cm TL based on characteristics and measurements of reproductive organs. A histological analysis showed that testes in males are a diametric type and have compound spermatozeugmata in the seminal vesicles, indicating sexual maturity in males at 180 cm TL. We recorded 40 pregnant females, with 14 to 40 embryos per female. The births occurred in July and August with an embryo size of between 41 and 51 cm TL. The presence of neonates, juveniles, and pregnant females with embryos in an advanced development condition suggest that the coastal waters off Oaxaca are an important nursery area for the scalloped hammerhead shark.
BASS, A. J., D’AUBREY, J. D. & KISTNASAMY, N. 1975. Sharks of the east coast of southern Africa. III. The families Carcharhinidae and Sphyrnidae. Oceanographic Research Institute, Durban. 100 pp.
BASS, A. J.1978. Problems in studies of sharks in the southwest Indian Ocean. In Sensory Biology of Sharks, Skates and Rays (Ed. E.S. Hodgson & R.F. Mathewson): 545-594. Office of Naval Research, Departament of the Navy. Arlington.
BRANSTETTER, S. 1981. Biological notes on the sharks of the North Central Gulf of Mexico. Contributions in Marine Science 24: 13-34.
BRANSTETTER, S. 1987. Age, growth and reproductive biology of the silky shark, Carcharhinus falciformis, and the scalloped hammerhead, Sphyrna lewini, from the northwestern Gulf of Mexico. Environmental Biology of Fishes 3 (19): 161-173.
BAUM, J., CLARKE, S., DOMINGO, A., DUCROCQ, M., LAMÓNACA, A. F., GAIBOR, N., GRAHAM, R., JORGENSEN, S., KOTAS, J. E., MEDINA, E., MARTINEZ-ORTIZ, J., MONZINI TACCONE DI SITIZANO, J., MORALES, M. R., NAVARRO, S. S., PÉREZ, J. C., RUIZ, C., SMITH, W., VALENTI, S. V. & VOOREN, C. M. 2007. Sphyrna lewini. In IUCN 2009. IUCN Red List of Threatened Species. Version 2009.2. <www.iucnredlist.org>.
CAMPUZANO, J. C. 2002. Biología y pesquería del tiburón martillo Sphyrna lewini (Griffith & Smith, 1834), en Puerto Madero, Chiapas, Mexico. Bachelor thesis dissertation. Universidad Nacional Autónoma de México. 210 pp.
CARLSON, J. K. 1999. Occurrence of neonate and juvenile of sandbar sharks (Carcharhinus plumbeus) in the northeastern Gulf of Mexico. Fishery Bulletin 97 (2): 387-391.
CASTRO, J. I. 1983. The Sharks of North American waters. A & M University Press. College Station, Texas.
CASTRO, J. I. 1993. The shark nursery of Bull 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.
CHEN, C. T., TZYH-CHANG, L. & SHOOU-JENG, J. 1988. Notes on reproduction in the scalloped hammerhead, Sphyrna lewini, in northeastern Taiwan waters. Fishery Bulletin 86 (2): 389-393.
CLARK, E. & VON SCHMIDT, K. 1965. Sharks of central Gulf coast of Florida. Bulletin of Marine Science 15(1): 13-83.
CLARKE, T. A. 1971. The ecology of the scalloped hammerhead, Sphyrna lewini, in Hawaii. Pacific Science 25 (2):133-144.
COMPAGNO, L. J. V., DANDO, M & FOWLER, S. 2005. Sharks of the World. Collins, London.
GALVÁN, F., NIENHUIS, H. & KLIMLEY, P. 1989. Seasonal abundance and feeding habits of sharks of the lower Gulf of California, Mexico. California Fish and Game 75: 74-84.
HAMLETT, W. C. 1999. Male reproductive system. In Sharks, Skates and Rays: the Biology of Elasmobranch Fishes. The Johns Hopkins University Press, Baltimore.
HAMLETT, W. C. & KOOB, T. J. 1999. Female reproductive system. In Sharks, Skates and Rays: the Biology of Elasmobranch Fishes. The Johns Hopkins University Press, Baltimore.
HAZIN, F., FISCHER, A. & BROADHURST, M. 2001. Aspects of reproductive biology of the scalloped hammerhead shark, Sphyrna lewini, off northeastern Brazil. Environmental Biology of Fishes 61:151-159.
KLIMLEY, A. P. & NELSON, R. 1984. Diel movement patterns of the scalloped hammerhead shark (Sphyrna lewini) in relation to El Bajo Espiritu Santo: a refuging central position social system. Behavioral Ecology and Sociobiology 15 (1): 45-54.
KLIMLEY, A. P. 1987. The determinants of sexual segregation in the scalloped hammerhead shark, Sphyrna lewini. Environmental Biology of Fishes 18 (1): 27-40.
KLIMLEY, A. P., CABRERA-MANCILLA, I. & CASTILLOGENIZ, L. 1993. Descripción de los movimientos horizontales y verticales del tiburón martillo Sphyrna lewini, del sur del Golfo de California, México. Ciencias Marinas 19 (1): 95-115.
PRATT, H. L. Jr. 1979. Reproduction of the blue shark, Prionace glauca. Fishery Bulletin 77 (2): 445-470.
PRATT,H. L. Jr. 1988. Elasmobranch gonad structure: a descriptive survey. Copeia 1988 (3): 719-729.
PRATT, H. L. Jr. 1993. The storage of spermatozoa in the oviducal glands of western North Atlantic sharks. In The Reproduction and Development of Sharks, Skates, Rays and Ratfishes. (Wourms, J. P. & Demski, L. S., eds). 38 (1-3): 139-149.
PRATT, H. L. & TANAKA, S. 1994. Sperm storage in male elasmobranchs: A description and survey. Journal of Morphology 219: 297-308.
SALOMON-AGUILAR, C. A., VILLAVICENCIO-GARAYZAR, C. J. & REYES-BONILLA, H. 2009. Shark breeding grounds and seasons in the Gulf of California: Fishery management and conservation strategy. Ciencias Marinas 35: 369-388.
SCHLERNITZAUER, D. A. & GILBERT, P. W. 1966. Placentation and associated aspects of gestation in the bonnethead shark, Sphyrna tiburo. Journal of Morphology 120 (3): 219-231.
SIERRA, P. 1995. Análisis preliminar de la pesquería del tiburón en Puerto Madero, Chiapas, Instituto Nacional de la Pesca, México.
TORRES, A. M. 1999. Observaciones sobre la biología reproductiva de la cornuda barrosa Sphyrna lewini (Griffith & Smith, 1834) (Pisces: Sphyrnidae) en aguas del noroeste de México. Bachelor thesis dissertation. Universidad Nacional Autónoma de México. 68 pp.