Population structure, age and growth of Callista chione (Bivalvia: Veneridae) in Martil Coast of the western Mediterranean

The smooth clam Callista chione is distributed in Moroccan Mediterranean coasts in considerable densities. This study examines the population structure, age, growth, mortality, longevity and exploitation level of the smooth clam on Martil coast. Samples were collected monthly from July 2016 to July 2017. Morphometric relationships were studied and showed negative allometric growth for the width/length, height/length and weight/length relationships. Four age groups were determined by Bhattacharya's method. Growth parameters were estimated from the Ford-Walford method to be L-infinity = 103.1 mm, K = 0.38 yr(-1) and t(0) = 0.43. Growth performance indices were found as phi' = 3.60 and P = 5.61. Total mortality, natural mortality and fishing mortality were estimated to be Z = 2.64 yr(-1), M = 0.55 yr(-1) and F = 2.09 yr(-1) respectively. The exploitation rate was calculated to be E = 0.79 proving an overexploitation of the species. The longevity was estimated to be 8 years. Results present necessary biological parameters to ensure the conservation, management and sustainable exploitation of Callista chione in Morocco. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The study investigated the population structure, growth, mortality, and exploitation level of the smooth clam on Martil coast in Morocco. The results indicate an overexploitation of the species and highlight the need for conservation and management efforts to ensure sustainable exploitation.