Biological parameters of grey wrasse Symphodus cinereus (Bonnaterre, 1788) (Pisces: Labridae) along the coasts of Rize in the south-eastern Black Sea

Abstract

The present study was designed to investigate the age distribution and growth properties of Symphodus cinereus in the south-eastern Black Sea. Data on the growth and age of S. cinereus were obtained by investigating sagittal otoliths. A total of 384 specimens (220 female, 164 male) were collected between June 2015 and May 2016 in the south-eastern Black Sea. Total lengths of male specimens ranged from 10-16.4 cm, whereas they ranged from 8.2-15.8 cm for females. The von Bertalanffy growth curve was used to describe length at age and considerable differences were seen between females (t(0) = -2.85, k = 0.296 and L-infinity = 16.46 cm) and males (t(0) = -2.84, k = 0.272 and L-infinity = 17.23 cm). The maximum age was 5 years. The relationship for males was W = 0.009L(3.2596) (r(2) = 0.9174, P < 0.005) and that for females was W = 0.0011L(3.1821) (r(2) = 0.9012, P < 0.005). While the highest condition (K) value was calculated in spring, the lowest value was determined in winter for both sexes. The obtained data also revealed monthly changes in the gonadosomatic index and maturity stages of male and female specimens, and the annual spawning season of this population began in March and ended in June. Fecundity ranged between 1375 and 5493 eggs/individual (mean: 2868.11 +/- 36-59.69 eggs), and the relationship between total length and egg production was highly statistically significant (P < 0.0001). This study provides the first data on the growth and reproduction of S. cinereus along the south-eastern Black Sea coast of Turkey.