Reproductive parameters of the Pacific angel shark Squatina californica (Selachii: Squatinidae).

Reproductive characteristics of the Pacific angel shark, Squatina californica, were evaluated from 420 specimens obtained from the artisanal fishery in La Paz Bay, Gulf of California, Mexico. Females (99 cm, 6000 g) were larger than males (95 cm, 5000 g) in terms of both total length (L(T)) and body mass (M(T)). The overall sex ratio was significantly different from the expected 1:1, suggesting sexual segregation of mature individuals in La Paz Bay. Males had developed reproductive organs and calcified claspers from 72 cm L(T); the median size at maturity (LT50 ) was 75.6 cm. In females, only the left ovary was functional and mature ovarian follicles were present from 77 cm L(T); the estimated LT50 was 77.7 cm. For the 10 gravid females sampled, uterine fecundity was between two and 10 embryos. Mature, non-gravid females with small and large ovarian follicles appeared simultaneously with gravid females with follicles that did not exceed 1.9 cm diameter.

Reproduction of the whitesnout guitarfish Rhinobatos leucorhynchus in the Ecuadorian Pacific Ocean.

Biological sampling of whitesnout guitarfish Rhinobatos leucorhynchus, caught as by-catch in the commercial fisheries on the Pacific coast of Ecuador, was conducted from specimens caught between April 2013 and January 2015, in order to provide further information on the reproductive biology of this species, for which data are limited. Samples comprised 1024 specimens (458 males and 566 females), with the sex ratio (1:1·23) significantly in favour of females. The total length (LT) ranged from 20·5 to 106·0 cm and showed sexual dimorphism, with females attaining a larger size. The relationship between body mass (MT) and LT was not significantly different between sexes. The length at 50% maturity for males based on internal reproductive organs was 60·9 cm LT , which was slightly larger than when based on clasper condition alone (58·5 cm LT). The LT at 50% maturity for females was 57·8 cm, and the LT at maternity was 65·1 cm. Fecundity ranged from one to seven embryos and LT at birth was 20-26 cm. According to oocyte development, two peaks of ovulation were observed (May to June and November to December). The ovarian cycle was estimated at 6 months and gestation between 5 and 6 months. Embryos showed different sizes all year-round, indicating an asynchronous cycle.