Pelagic larval duration and early growth of striped seabream, Lithognathus mormyrus inhabiting the Gokceada shallow waters, Turkey

Abstract

Otolith microstrure analysis was used to determine the pelagic larval duration (PLD), daily age, growth rates, hatching periods, and the mortality rates of the young of the year (YOY) striped seabream from Gokceada, Turkey. This study was carried out in shallow waters (0-20 m) off the Gokceada Island, Turkey, from June 2013 through June 2014. A total of 632 YOY striped seabream, Lithognathus mormyrus were measured and daily ages determined. Estimated ages from otolith daily growth increments (DGI) were found 28-218 days old. The indices for determining variability in daily age estimates (APE and CV) were 4.1 and 5.8%, respectively. The mean daily growth rate of YOY striped seabream was calculated as 0.317 mm/day. Individuals with YOY sea stingrays have been found to remain in the pelagic larval duration for an average of 26 days and settled in the demersal environment after the 26th days. The hatching times of striped seabream were backcalculated to occur between April and January, with relatively higher hatching frequencies in July and December. The instantaneous mortality coefficient was found as 0.0461, which represented around 4.61% of daily mortality. Sagittal otolith length (OL), width (OW), and radius (OR) were observed in the ranges of 0.741-3.283 mm, 0.586-1.921 mm, and 0.259-1.626 mm, respectively. Relationships between total length and otolith morphometric measurements (OL, OW, and OR) were described by linear equations.