Early larvae ontogeny of the Neotropical fishes: Prochilodus costatus and P. argenteus (Characiformes: Prochilodontidae)

• Published in: Revista de biología tropical Vol. 64; no. 2; pp. 537 - 545
• Main Authors: dos Santos, José Enemir, Sales, Naiara Guimarães, dos Santos, Marcella Lourenço, Arantes, Fábio Pereira, Godinho, Hugo Pereira
• Format: Journal Article
• Language: English
• Published: Costa Rica Universidad de Costa Rica 01-06-2016
• Subjects: Animals; Biodiversity Conservation; Biology; Characiformes - anatomy & histology; Characiformes - classification; Characiformes - embryology; Female; Larva - anatomy & histology; Larva - classification; Larva - growth & development; Male; larval ontogenic; swimming behaviour; larvae development; larval rearing; comportamiento de natación; cría de larvas; desarrollo de la larva; Prochilodontidae; ontogenia larval
• ISSN: 0034-7744
• DOI: 10.15517/rbt.v64i2.19052

Early development of fish larvae is a highly dynamic process and its study may provide important
information about ontogenetic development, bioenergetic growth, behaviour, taxonomic characteristics for identification
in natural environments, identification of spawning areas, and population monitoring. With the aim to
provide knowledge about their growth and behaviour, to support larval rearing, and also taxonomic purposes, we
studied the life history of the Prochilodus argenteus and P. costatus from hatching until the complete absorption
of the yolk. Larvae were obtained through artificial reproduction at the Hydrobiology and Aquaculture Station
of Três Marias, Minas Gerais, Brazil. Immediately after hatching, 100 larvae of each species were put in two
plastic incubators for conditioning. On a daily basis, larvae behavior was recorded and 14 larvae of each species
were collected to analyse body morphology. On the first day after hatching, larvae of P. costatus and P. argenteus
showed an elongated and transparent body; the yolk sac was filled with individualized yolk globules. In both
species, the embryonic fin rounded the caudal region of the body, the retina was non-pigmented and the gut was
obliterated. At the second day post-hatching, larvae of both species dendritic chromatophores had emerged, the
mouth was obliterated and the pectoral fin was observed. The larvae showed 38-43 myomeres in P. costatus and
42-43 in P. argenteus. For both species, the gas bladder was inflated and the lumen of the gut was already open.
On the third day post-hatching, the mouth of P. costatus and P. argenteus was already open in a sub-terminal
position; the retina was pigmented; the gill arches had lamellar protrusions and were partially covered by the
operculum. On the fourth day post-hatching, the pigmentation pattern was maintained with greater intensity; the
mouth occupied a terminal position, the yolk sac was almost completely reabsorbed, and the pectoral and caudal
fins showed mesenchymal rays in both species. The gut showed a broad lumen with folded mucosa and epithelium
with striated border. The larvae of both species showed similar swimming behaviour. Our study provided
understanding about the morphophysiological aspects, species identification, larval development and growth,
and the ontogenic characteristics of two Neotropical fishes with importance for commercial and sports fishing.