Reproductive biology of the Chilean eagle ray, Myliobatis chilensis (Myliobatiformes: Myliobatidae), disembarked in the port of Salaverry, Peru

Valderrama-Herrera M.; Culquichicón Z.; Kanagusuku K. · Scientia Marina (2026) · DOI: 10.3989/scimar.05627.119

Resumen

Myliobatis chilensis, commonly known as the Chilean eagle ray, is a benthopelagic species found along the Humboldt Current. Peruvian fisheries target it, but little is known about its life history. This study aimed to gather information on the reproductive biology of M. chilensis from Salaverry. A total of 160 individuals from monthly landings between October 2017 and November 2018 were analysed, with data collected on sex, disc width (DW), clasper calcification, weight, liver and gonads. Sexual maturity was determined by comparing clasper length and clasper calcification in males and by gonadal structure in females. Eighty male individuals (41–153 cm DW) and 80 female individuals (42–221.6 cm DW) were obtained, yielding a sex ratio of 1F:1M. The average ovarian fertility was 32 oocytes, and the median size at sexual maturity was estimated to be 163 cm DW for females and 122 cm DW for males. Histological samples were processed by inclusion in paraplast and stained with haematoxylin and eosin for corroboration. Five stages of ovum development and 11 stages of spermatozoan development were observed. Based on these microstructural observations, a maturity scale with easily distinguishable stages was constructed. The study found that gonads are the sole indicators of maturity in females, while claspers serve as excellent indicators in males. Only mature ovaries were sampled from the second half of each year, and no embryos were found. These reproductive insights are expected to assist in decision-making for sustainable management.

Instituciones: Universidad Nacional de Trujillo; Universidad Científica del Sur