Age, growth, length–weight relation, and reproduction of sand steenbras, Lithognathus mormyrus (Actinopterygii: Perciformes: Sparidae), in the Köyceğiz Lagoon, Mediterranean

Abstract

Background. Sand steenbras, Lithognathus mormyrus (Linnaeus, 1758), has high commercial value and constitute an important catch for the coastal and lagoon fisheries in the Mediterranean. The information about the biology of this species in the lagoons of Turkey is very limited. This study provides updated data about age, growth, length–weight relation, and reproduction period for sand steenbras. Materials and methods. A total of 319 samples were caught from the Köyceğiz Lagoon, Turkey, in monthly intervals, from January to December 2017, using a fish barrier, trammel net, beach seine, and cast-net. The fish age was determined from sagittal otoliths. Growth parameters were investigated by applying the von Bertalanffy growth function. Results. The total length of females ranged from 12.5 to 24.1 cm, total length of males ranged from 11.7 to 23.4 cm, total length of intersexuals ranged from 15.5 to 22.3 cm, total length of immature ranged from 2.5 to 12.4 cm, and total length of all individuals ranged from 2.5 to 24.1 cm. The female ÷ male ratio was estimated at 1 ÷ 0.79. The age of the sand steenbras individuals ranged from 0 to 5 years for all individuals. The growth parameters of the von Bertalanffy equation were: L∞ = 30.2 cm, K = 0.234 year–1, and t0 = –1.30 year for females, L∞ = 29.7 cm, K = 0.238 year–1, and t0 = –1.28 year for males and L∞ = 28.6 cm, K = 0.284 year–1, and t0 = –0.86 year for all individuals. The length–weight relations of females and males were W = 0.0132L3.024 (r2 = 0.947) and W = 0.0169L2.941 (r2 = 0.960), respectively. Reproduction period continued from late April (19.1℃) to early June (25.9℃) with the greatest intensity occurring in May (GSI = 5.879, 24.0 ℃). Conclusion. This study provides first information related to age, growth, reproduction period and length–weight relations of the sand steenbras from the Köyceğiz Lagoon. These results may be used in future studies on this fish and may contribute to a more effective fisheries management in the Köyceğiz Lagoon.

Keywords

• Köyceğiz Lagoon
• Lithognathus mormyrus