Growth and reproduction of the wedge clam (Donax trunculus) in the Sea of Marmara, Turkey

Abstract

Summary Reproduction, growth and mortality of the wedge clam Donax trunculus were studied in an unexploited population in the northern part of the Sea of Marmara. Age determination was based from counting shell increments by inspection of both the external ring structure and the internal structure on thin cross-sections of the shell. Maximum life span was observed as 6 years for the studied population, but 4 years (shell length 40–41 mm) were usually not exceeded. Maximum length was 44.8 mm. Growth parameters were estimated as L∞ = 44.15 mm, k = 0.62 year−1, C = 1 and WP = 0.83 from external ring structure, and L∞ = 42.44 mm, k = 0.75 year−1, C = 1 and WP = 0.79 from internal growth bands (thin section). Natural mortality (M) was estimated as 0.98 year−1. Sex ratio was not significantly different from 1 : 1. The monthly maturation process was assessed macroscopically and from variation in the mean total ash-free dry weight per shell weight of adult individuals. Spawning occurred between April and July with a peak between May and June. The recruitment pattern was unimodal.