Turkish Journal of Fisheries and Aquatic Sciences
2023, Vol 23, Num, 3 (Pages: TRJFAS21901)
Length Based Assessments for European Pilchard Sardina pilchardus and European Anchovy Engraulis encrasicolus, in the İzmir Bay, Aegean Sea
2 Tokyo University of Marine Science and Technology, Department of Marine Biosciences, Tokyo 108-8477, Japan
3 Istanbul University, Institute of Marine Sciences and Management, İstanbul 34134, Turkiye DOI : 10.4194/TRJFAS21901 Viewed : 4342 - Downloaded : 1421 In the Mediterranean Sea, European pilchard Sardina pilchardus and European anchovy Engraulis encrasicolus are the most important small pelagic fish regarding their ecological role, and revenue. Here, we perform a comprehensive assessment of length-based methods for those small pelagics from İzmir Bay, Aegean Sea. Therefore, the Length-based Bayesian Estimator and Length-based Spawning Potential Ratio were used to evaluate the stock structure and status of two important small pelagic fish. The length range for Sardina pilchardus was from 7.1 cm to 17.3 cm in TL. The ratios Lmean/Lopt and Lc/Lc_opt were over 1, suggesting truncated length structure and fishing of not too small individuals. The proportion of mature individuals in the catch was far less than half (36%) suggesting that in these fisheries catch consists mostly of immature individuals. The length range for Engraulis encrasicolus was from 5 cm to 15 cm in TL. The ratios Lmean/Lopt and Lc/Lc_opt were over 1 (1.2 and 1.3, respectively), suggesting truncated length structure and fishing of large individuals. The proportion of mature individuals in the catch was over half (52%) suggesting that in these fisheries catch consists of adults. The estimated sizes at median 50% selectivity (SL50) for S. pilchardus (11.1 cm) was ∼0.6 cm shorter than its lengths at 50% maturity (L50) of 11.7 cm, which indicates that a large proportion of the catch was immature. The median estimate of the spawning potential ratio was ∼0.19 for S. pilchardus and ∼0.48 for E. encrasicolus. Keywords : Length-frequency Spawning potential ratio Data-limited fisheries Sardine Anchovy Fisheries management