A first study on growth, mortality and survivorship of the eared horse mussel, Modiolus auriculatus (Krauss, 1848) from India

Abstract

Present study is the population dynamics of the eared horse mussel, Modiolus auriculatus carried out from a rocky intertidal beach located in Byndoor beach along Karnataka coast, south west coast of India. M. auriculatus were collected from June 2010 to May 2011 for length-frequency distribution analysis. A total of 1205 mussels ranging in size from 2.64 to 25.91 mm were measured. Asymptotic length (L∞) of the von Bertalanffy growth function was 27.77 mm and the growth coefficient (K) was 0.62 year−1. The value of to for M. auriculatus was -0.267 year in the present study. Growth performance index (ϕ′) was 2.68. Average growth rates of 4 years were 1.26 mm, 0.49 mm, 0.26 mm and 0.14 mm in the 1st, 2nd, 3rd and 4th years of age, respectively. The life span of this species was 4.1 years based in our study. The total mortality (Z) was calculated as 2.31 year -1. Two major peaks of monthly mortality rate were found in August (4.6586, primary) and January (2.9402, secondary). The values of survival level ranged from 0.3651 (August) to 0.9330 (March). The shape of the survivorship curve is sigmoidal in the study.