Early development of pearlside Maurolicus stehmanni off south‐eastern Brazil

Abstract

The pearlside Maurolicus stehmanni is one of the most abundant mesopelagic fishes off south‐eastern Brazil and plays a key role in the regional ecosystem. However, its early life history remains poorly understood. This study examined the M. stehmanni early life stages, from eggs to juveniles, including all developmental changes in external morphology. Larvae are simple in morphology and lack specialized larval structures. Notochord flexion begins at ~5.15 mm body length (BL) and larvae ≥5.95 mm BL are flexed. The relative growth of seven measured larval characters (head length, body depth, snout length, eye diameter, pre‐dorsal length, pre‐ventral length and pre‐anal length) have transition points (allometric inflexion points), indicating biphasic growth patterns which are likely related to shifts in habitat use, feeding and behaviour. Larval development is similar to that of other Maurolicus species. The relatively fast development of the fins, photophores, swimbladder and pigmentation suggests a precocious adoption of a micronektonic lifestyle in the mesopelagic environment.

Early ontogeny of the commercially valuable fish red‐bellied pacu Piaractus brachypomus (Characiformes, Serrasalmidae) from the Amazon, Brazil

“…This enables the larvae to react to visual stimuli and maximize their motor and sensory abilities, facilitating the detection of prey (Blaxter, 1988; Gisbert et al ., 2002). The changes recorded in BD, SnA and SnV may reflect an improvement in swimming performance (Rodrigues‐Ribeiro et al ., 2022), enabling a greater interaction between species and the environment, consequently maximizing the chances of survival.…”