C. Andre et M. Lindegarth, FERTILIZATION EFFICIENCY AND GAMETE VIABILITY OF A SESSILE, FREE-SPAWNING BIVALVE, CERASTODERMA-EDULE, Ophelia, 43(3), 1995, pp. 215-227
The fertilization biology of the free-spawning bivalve Cerastoderma ed
ule was studied in the laboratory. Fertilization success declined dras
tically with decreasing sperm concentration. Viability of both eggs an
d sperm decreased with age so that no fertilization took place after 4
-8 hours. A dilution model suggests that in the field sperm is rapidly
diluted to concentrations that would result in very low fertilization
efficiencies. The dilution process thus operates on a much smaller ti
me scale than gamete ageing, indicating that most eggs are fertilized
close to spawning males. However, it is also shown that under certain
circumstances high concentrations of sperm may accumulate over dense p
opulations of bivalves.