Energetic parameters of a population of Chlamys varia (Bivalvia: Pectinidae)

Abstract

Energy relations of a population of black scallop C. varia (L.) in Lanveoc (Bay of Brest, France) were studied from 1976-1978. The population had a production of 538.52 kcal 100 m-2 and of 497.10 kcal 100 m-2 during the years 1976-1977 and 1977-1978, respectively; it assimilated 5773.21 kcal 100 m-2 during the 1st yr and 4561.21 kcal 100 m-2 during the 2nd yr of this study. Net production efficiency of black scallops (9-12%) was very low compared to that of other bivalve populations reported so far. Average annual biomass of the population studied was 1252.59 kcal 100 m-2 and 956.06 kcal 100-2 during the 2-yr period of study. Considerable energy was eliminated by the population due mortality (natural and fishing mortality): 1017.42 kcal 100 m-2 and 939.51 kcal 100 m-2 during the 1st and 2nd yr, respectively. Average energy utilized for production of organic matter: average biomass ratios were 0.43 and 0.52 during the 2 yr.