Age, Growth and Condition Index of Venerupis decussata (Linnaeus, 1758) in the Eastern Adriatic Sea

Abstract

Age, growth and condition index of commercially important chequered carpet shell Venerupis decussata (Linnaeus, 1758) were studied in the Pag Bay - eastern Adriatic Sea. Monthly samples were collected from commercial catch from January to November 2007. Age and growth were determined from internal growth bands of 69 shells ranging in length from 17.7 to 43.5 mm. Marginal increment analysis performed on 68 shells (26.4±3.4 mm) confirmed that growth bands are annually formed in February. Condition index was determined monthly on 30 specimens, and maximal value was recorded in April. Formation of growth bands corresponded to a period of slow growth which was recorded prior to the increase of condition index. Distance from the umbo to the each visible growth ring was measured and growth parameters L∞ and k were estimated using the Gulland-Holt method (38.73 mm and 0.52 year-1, respectively) and by fitting length at age data to a von Bertalanffy growth curve (37.91 mm and 0.57 year-1). Majority of analysed specimens were two years old and the oldest specimens analysed had six years. In conclusion, these data suggest that V. decussata is a short - living species with the most intensive growth occurring during the first two years.