Gonadal development and reproductive traits of pacific flat sleeper Dormitator latifrons (Gobiiformes: Eleotridae): insights for sustainable management in Ecuador

Abstract

The Pacific sleeper, Dormitator latifrons, is a fish native to the eastern central Pacific that is under increasing human pressure. The harvesting of adults for consumption and juveniles for aquaculture highlights the urgent need to understand its biology for management purposes. This study developed a macroscopic and histological gonadal development scale, described genital papilla morphology, and evaluated sex ratio, size at maturity, and oocyte development. Between December 2017 and August 2018, 295 specimens were collected from the Carrizal-Chone River, Ecuador. Total length, weight, and sex were recorded, and reproductive organs were analyzed. The male-to-female sex ratio was 1.05:1. The genital papilla varied in size and appearance with gonadal development. A universal five-phase histological scale accurately identified reproductive phases: immature, developing, spawning capable, regressing, and regenerating. The ovarian development was group-synchronous, suggesting a total spawning strategy. Unfertilized oocytes were spherical, with a thin capsule, 4 to 8 oil droplets, and longitudinal striations. Oocyte size distribution revealed mature and immature populations. The length at 50% maturity (L50) was 13.26 cm for females and 12.09 cm for males. These findings allow a more precise understanding of the life history of D. latifrons, and may contribute to the definition of conservation and sustainable resource management.