Larval development of the freshwater croaker Pachypops fourcroi (La Cépède 1802) (Perciformes: Sciaenidae)

Abstract

The larval development of Pachypops fourcroi from the lower Amazon River was described through morphological, meristic and morphometric features. Sixty‐five larvae were examined and present a moderate body, slightly elliptical eyes and head ranging from moderate to large. The mouth is initially terminal and becomes subterminal throughout development with three barbels in the mentonian region. The larvae of P. fourcroi can be differentiated from other Sciaenidae in the Amazon basin by the pigmentation pattern, the presence of barbels, head depth, body depth and diameter, and shape of the eye.

Early development ofProchilodus nigricansSpix & Agassiz 1829 (Characiformes: Prochilodontidae) in captivity

“…The opening and functioning of the mouth and anus, together with the pigmentation of the eyes are events that occur simultaneously during the preflexion stage and are linked to the beginning of exogenous feeding of larvae (boiled egg yolk, diluted in water; Cajado et al, 2021; Oliveira et al, 2021; Silva et al, 2021), therefore, P. nigricans larvae were able to receive exogenous feeding from 3 days posthatching and presented a feeding transition period between three and 4 days posthatching. This change from endogenous to exogenous feeding is considered critical for larval survival, being a crucial moment for larviculture success (Abdo et al, 2015), since feeding in the first days of life is one of the main obstacles in the production of fingerlings (Silva et al, 2013).…”

“…The myomeres correspond to the number of vertebrae (all segments of the spine, including the urostile and incorporated the Weber apparatus equivalent to the fusion of four vertebrae) plus one (Snyder, 1979). Thus, the total or partial number of myomeres is considered an important character for the identification of fish larvae (Cajado et al, 2021; Oliveira et al, 2021; Santos et al, 2020; Silva et al, 2021).…”

“…Thus, the total or partial number of myomeres is considered an important character for the identification of fish larvae (Cajado et al, 2021;Oliveira et al, 2021;Santos et al, 2020;Silva et al, 2021).…”

“…After hatching, the individuals were categorized according to the flexion of the final section of the notochord and the development sequence of the fins and their supporting elements, in (I) larval period comprising four stages: (a) yolk sac, (b) preflexion, (c) flexion and (d) postflexion; and (II) juvenile period (Ahlstrom et al, 1976; modified by Nakatani et al, 2001). These classifications are widely adopted in several morphological characterization studies of the early stages of life of freshwater fish (Cajado et al, 2021; Lima et al, 2021; Oliveira et al, 2020; Oliveira et al, 2021; Santos et al, 2020; Silva et al, 2021).…”

“…It is emphasized that although the Amazon region has the greatest fish biodiversity in the world, there are still few studies that address the description of the early ontogeny of fish species (Zacardi et al, 2020). However, knowledge of larval phases is pivotal to assist in the management and conservation of tropical fishery stocks (Cajado et al, 2021; Oliveira et al, 2021; Silva et al, 2021).…”