Population ecology of freshwater mussel Parreysia corrugata (Mullar 1774) from River Malthi, Tributary of river Tunga in the Western Ghats, India
Keywords:
Freshwater mussel, Parreysia corrugata, age and growth, mortality, Karnataka, Western Ghats.Abstract
The The freshwater mussel Parreysia corrugata (Muller, 1774) is common in rivers of India. The growth, mortality and recruitment of P. corrugata were studied from March 2007 to June 2008 from river Malthi, tributary of river Tunga, in the Western Ghats. A total of 1587 individuals ranging from 17 to 57 mm size were subjected to analysis. The recruitment pattern produced one cohort per year and the highest peak occurred during November-December. In the first year the growth of mussel was fast, about 50% of its maximum size, and in subsequent years the growth decreased. The sizes attained by P. corrugata were 22, 36, 46, 51, 55 and 57 mm at the end of 1st to 6th years respectively. The average growth rates of P. corrugata from first to sixth years were 2.00 1.08, 0.75, 0.5, 0.25 and 0.17 mm/month respectively. The life span of the mussel was about 6 years at the study area. The von Bertalanffy growth equation for length was Lt = 60.76 [1- e-0.47 (t +0.0426)]. The growth performance index (Φ) was 3.896. The total mortality (Z) was 1.84/ year. The natural mortality (M) and fishing mortality (F) rates were 0.9 and 1.19/year respectively. The exploitation level (E) of P. corrugata was 0.57.