Metamorphosis of whitemouth croaker Micropogonias furnieri (Pisces, Sciaenidae).

BRAVERMAN, M.; BROWN D.; ACHA E.M.

Marine and Fishery Sciences

INIDEP

Lugar: Mar del Plata; Año: 2020 vol. 33 p. 163 - 182

2683-7595

Metamorphosis is an important ontogenetic process for fish with consequences on the survival of early stages and plays a key role into successful recruitment to adult populations. Metamorphosis was studied in the whitemouth croaker, Micropogonias furnieri, an important commercial resource for Argentina and Uruguay. Changes in morpho-meristic characters before and after metamorphosis were employed to determine the length interval of this transition by employing Principal Component Analysis. Individuals (n=120) from 4 to 34 mm standard length (SL) were collected in the Río de la Plata estuary (-35.45º S, -56.35º W) in March, 2006. Length ranges of individual´s developmental stages were associated with appearance/disappearance of key morphological characters. During early life stages, M. furnieri changes from a larval robust shape with a big head to a more elongated body shape. Most of the morphometric variables showed an inflexion point at 15.2 mm SL with a confidence interval of 14 ? 16.4 mm. The anterior part of the body grows faster during early stages, being probably related to feeding. The completion of pectoral fin rays and the onset of squamation determine the beginning of metamorphosis, at 11-12 mm SL. Squamation ends at around 18 mm SL, at the same time the first barbels develop and the otolith primordium is closed. The length-at-metamorphosis for M. furnieri was established in the interval 9 to 18 mm SL, since all developmental characters studied highly overlapped at that interval. Such process determines the beginning of the juvenile period being associated to settlement.