GROWTH RATE, LONGEVITY AND MAXIMUM SIZE OF MACOMA BALTHICA (L.)

¹ Department of Zoology, University of Massachusetts, Amherst, Massachusetts and Marine Biological Laboratory, Woods Hole, Massachusetts 02543

1. Growth rate and longevity were determined for a population of M. balthica at Rand Harbor, Falmouth, Mass., using a modification of the mark and recapture technique that allowed all marked individuals to be followed throughout a year. Dry weight biomass, dry shell weight and caloric content were also determined.

2. Caloric content is 4.049 kcal/ash-free g. Dry weight biomass and dry shell weight were found to have a similar allometric growth with a constant of allometry of approximately 3 when measured against shell length.

3. The bivalves were discovered to grow year round with the peak period of growth occurring from May to August. A negatively linear relationship between initial length (X) and total annual increment (Y) was found (Y= -0.59 X + 12.85).

4. The growth curve for the Rand Harbor population revealed that within the first two years of life, M. balthica attains most of its total length. Growth ceases once a maximum size of 22-25 mm is reached and total longevity is estimated to be 6-10 years.

5. These results were compared to other studies and the theory that maximum size, growth rate and longevity are controlled by temperature presented and discussed.