Abundance and spatial distribution of the fish eggs and larvae of european sprat, Sprattus sprattus in the Sea of Marmara, Türkiye.

Abstract

European Sprat, Sprattus sprattus (Linnaeus, 1758), is recognized as one of the most representative small pelagic fish species in the Black Sea and the Sea of Marmara (SoM). Scientific data on the early life characteristics of Sprat stocks in the SoM have been insufficient. In the present study, we aimed to elucidate the mean abundance of fish eggs and larvae, as well as their spatial and temporal variations in the SoM. To achieve this, three ichthyoplankton surveys were conducted in December 2021, January 2022, and March 2022 across 32 equally distributed stations covering the entire Marmara Sea. Sprat eggs and larvae were collected using vertical plankton tows with a WP-2 type plankton net equipped with a 300 μm mesh. Among all winter spawners in this study, Sprat was the most abundant fish species for both eggs and larvae, comprising 90.1% and 61.9% of the total abundance, respectively. The mean Sprat abundance per unit area (n/10 m²) was determined to be 713.8 n/10 m², with mean prelarvae abundance at 43.5 n/10 m² and postlarvae at 16.9 n/10 m². A total of 80.3% of the fish eggs, with a mean of 1719.9 n/10 m², and 73.6% of the total larvae abundance, with 133.6 n/10 m², were observed in February. Three primary spawning grounds were identified: the Karacabey Floodplain area (S18), Büyükçekmece shores (S23-S26), and Tekirdağ shores (S8), with larval movement observed from the northern to the southwestern regions and possibly from S18 to the southwestern part.