INVESTIGADORES
LUCIFORA Luis Omar
artículos
Título:
Reproductive ecology and abundance of the sand tiger shark, Carcharias taurus, from the southwestern Atlantic
Autor/es:
LUIS O. LUCIFORA; ROBERTO C. MENNI; ALICIA H. ESCALANTE
Revista:
ICES JOURNAL OF MARINE SCIENCE
Editorial:
Elsevier
Referencias:
Año: 2002 vol. 59 p. 553 - 561
ISSN:
1054-3139
Resumen:
This study analyses the sexual activity and segregation of sand tiger sharks, Carcharias
taurus, from Anegada Bay (Argentina). Reproduction-linked movements along the
South American Atlantic coast were inferred from data from several SW Atlantic
localities. Male sand tigers (n = 162) matured at 193 cm total length (LT). Females
(n = 77) matured between 218 and 235 cm LT. These figures are similar to those from
other populations, although size-at-maturity of males was slightly different from South
African and Australian populations. In females, the size of ovarian follicles was
positively correlated with gonadosomatic index and negatively correlated with hepa-
tosomatic index, while the liver was significantly larger than in males. Sand tiger sharks
were present in Anegada Bay from December to April. Males were significantly more
abundant than females (2:1). Significant differences in reproductive condition through
time were observed in males. During January and February males had seminal vesicles
full of spermatozeugmata but by March and April the vesicles were empty. As the
proportion of males with a lighter colouration peaked from January to March, it is
very likely that mating takes place during January and February. The skewed sex-ratio
during the mating season indicates a possible strong competition for mates among
males, as observed in captivity. Males, females and some juveniles occur in Argen-
tinean and Uruguayan waters, where mating takes place. Pregnant females occur in
subtropical waters of southern Brazil, where they give birth. Given that pregnant and
non-pregnant females occur at the same time in different zones, we suggest that the
female reproductive cycle is biennial. Striking differences among migratory patterns of
sand tiger sharks from the SW and NW Atlantic and South Africa were observed.