Reproductive biology of the crocodile shark, Pseudocarcharias kamoharai, in the Ecuadorian Pacific Ocean

Abstract

The crocodile shark, Pseudocarcharias kamoharai, is frequently caught by the artisanal fleet of Ecuador. However, updated official records concerning its landings and knowledge regarding its reproductive biology and ecological traits are scarce in the Tropical Eastern Pacific Ocean. Therefore, this study aimed to describe the reproductive biology of P. kamoharai and determine the capture composition of immature and mature individuals in Santa Rosa, Ecuador. Samples were collected from June 2012–May 2013 and June 2017–May 2018. 408 sharks were collected including 202 females ranging from 50 to 117 cm in total length (TL), and 206 males ranging from 72.5 to 110 cm TL. The sex ratio in adults was 1F:1M, similar to the fetus’s ratio of 0.9F:1M. Histotrophy in the uteri of mature females was recorded for the first time. Size at maturity (L50) was estimated at 91.2 cm TL for females; hence, 88% (n = 177) were mature. While for males, L50=84.8 cm TL; thus, 84% (n = 174) were mature. Gravid females were observed from February to November, and fetuses had different sizes without a growing trend pattern. Thus, gestation and time of birth could not be defined. Size at birth was 45.5 cm TL and fecundity was four fetuses per litter, two for each uterus. In conclusion, this species is susceptible to overfishing due to its low biological productivity. The information generated in this study supports creating a fishery management plan for future conservation.