Dl. Stites et al., POPULATION-DYNAMICS, GROWTH, AND PRODUCTION OF THE ASIATIC CLAM, CORBICULA-FLUMINEA, IN A BLACKWATER RIVER, Canadian journal of fisheries and aquatic sciences, 52(2), 1995, pp. 425-437
In a sixth-order blackwater river (Lower Coastal Plain of Georgia, USA
), the average life span of Corbicula fluminea (Muller) was 3-4 years,
with shell length reaching only 18-20 mm by the third year. Mean dens
ity was usually < 200/m(2) over a 43-month period, but > 1000/m(2) in
population centers. Mean biomass (dry mass of soft tissue) was consist
ently 1-5 g/m(2), but averaged 11 g/m(2) in population centers. Biomas
s growth rates of clams reared in situ were highest in late spring and
were inversely related to clam mass. Production ranged from 0.18 g .
m(-2). year(-1) at a main-channel site to 3.2 in a backwater and avera
ged 1.2-1.7 for 2 consecutive years. In population centers, production
reached 9-23 g . m(-2). year(-1). Production was highest in spring an
d fell to zero in winter when growth ceased. Annual production/biomass
values were about 4-8 for first-year individuals, but ranged from 0.5
1 to 1.78 overall. Individual size, growth rates, and production all i
ndicated that this blackwater river was a stressful environment for Co
rbicula, probably due to low alkalinity (< 30 mg/L as CaCO3). Unlike i
ts effect in many other systems, the clam appears to play a minor role
in the trophic dynamics of this river.