Validated age and growth estimates of two clam species in a saltwater lake on the Suez Canal in Egypt

Abstract

This is the first time to document the validated age and growth estimates for two clam species; Ruditapes decussatus, and Gafrarium pectinatum in Lake Timsah, which is a salt water lake on the Suez Canal in Egypt. Age validation for the two species was done to confirm the annual deposition of each growth increments on the shell surface and was conducted using the edge analysis method. Age validation of these two species showed that the period of the major growth was summer, while the slower growth was documented in winter. The age of the two species was determined by counting the growth increments on the shell surface. Maximum age for R. decussatus (4 y) and G. pectinatum (3 y) were recorded in a 37.2 mm and 42.1 mm in the two species, respectively. Also, length frequency analysis using FiSAT was used to confirm the number of year classes (age) in the two species. The von Bertalanffy Growth Parameters; L∞, k and to, were 40.4 mm, 0.268 and -1.11y for R. decussatus and 36.3 mm, 0.81 and 0.05 y for G. pectinatum. Besides age, the morphometric characters of the two species were discussed. The results of this study will help in better fisheries and ecosystem management. Keywords: