| Some parameters measuring the production of organic matter, in field conditions, by a population of the bivalve mollusc Donax trunculus have been studied. Those studies which are easily done when the population is composed of long lived species become difficult in Mediterranean Sea where the populations are instable and composed of short-lived species. A large qualitative sample has been made every month on which the interpretation of cohort succession has been done using the graphical method of CASSIE (1954) which is an useful mean to determine the modal class-size. The monthly values of the weight/size relationship, during a year, show important fluctuations indicating that size increment, tissue weight increment, gamet production and release are often... |
