Reproduction of European Pilchard, Sardina pilchardus (Walbaum, 1792) in the Aegean Sea

Authors: Bülent CİNAHGİR

Abstract: In order to understand the repdoductive biology of the European sardine Sardina pilchardus (Walbaum, 1792) which shows a wide distribution in the Aegean Sea, monthly fish samplings were made in the Edremit Bay (Area I), the İzmir Bay (Area II), and Büyük Menderes Delta (Area III) during the period of 1988 to 1990. It is determined that the reproduction process takes place between the months of September to May along the Turkish coast of the Aegean Sea. The following statistical values were obtained, respectively, for the areas mentioned above: Lengths at first sexual maturation are 12.0, 12.4, 12.2 cm for males and 11.3, 12.2, 12.2 cm for females; sex ratios (female: male) are 1: 0.28, 1: 0.83, 1: 0.82; according to the gonadasomatik index (GSI), the maximum repdoduction period is in the months of December, January, and February, which have the lowest sea water temperatures. As a multiple spawning indicator, it is possible to find various sizes of eggs all together in the ovary during the reproduction period, observed from the morphological and histological investigations. Batch fecundity is given below for the respective areas: Y=0.0072666 X5.0668, Y=0.00029413 X6.2422, Y=0.00030273 X6.1990, according to the total length; and, Y=48.080 X1.5061, Y=61.123 X1.3772, Y=10.853 X1.8838 according to the gonad free weight. Relative fecundity is 279.2 (SD 75.2), 224.8 (SD 81.0), and 233.6 (SD 69.0) eggs/g for females; spawning frequencies are 9.8, 8.0, and 8.6 days, respectively for the areas. The condition factor shows an increase beginning at the end of spring and extending into Autumn. The lowest and highest condition factors were determined to be in the months of January (0.70-0.80), and October (1.12), respectively.

Keywords: European Sardine, Repdoduction.