Feeding rates and scope for growth of green mussels, Perna viridis (L.) and their relationship with food availability in Kat O, Hong Kong

Abstract

The feeding and absorption rates (ARs) of the green mussel Perna viridis (L.) were studied from December 1997 to November 1998. During each visit, characteristics of seston including concentrations of total particulate matter (TPM), particulate organic matter (POM), particulate inorganic matter (PIM) and organic fraction of seston ( f) were also determined. Higher values of clearance rates (CRs), ARs and absorption efficiencies (AEs) were obtained from November to January and lower values in March and April. CR was a negative power function of TPM and a positive linear function of f. ARs and AEs were significantly correlated with TPM and f ( P<0.001), showing that food availability (both seston quantity and quality) was the key factor influencing feeding behaviour of P. viridis. The activity of amylase and cellulase in the digestive gland and crystalline style, and the scope for growth (SFG) were determined in February, May, July and October to represent the situation in winter, spring, summer and autumn, respectively. There was no correlation between digestive enzyme activities and seasons except for amylase activity in the digestive gland. SFG was lowest in February and highest in October, and was correlated with f.