A bay scallop, Argopecten irradians irradians (Lamarck 1819), population was studied in Little Egg Harbor, New Jersey, USA to investigate the distribution, reproduction and genetic structure of the population because virtually nothing is known about this species in this region. Argopecten irradians irradians densities varied among eelgrass (Zostera marina Lamarck) beds in 1998 (range 0.12-1.0 individuals per 10m transect), but were virtually absent from the region in 1999. The absence of adults in 1999 may have been due to limited spat recruitment and survival in the fall of 1998, which may be attributed to a reduction in above ground biomass of Z. marina habitat. Genetic analysis (using mtDNA) indicated that this New Jersey population was intermediate between New York and North Carolina populations. Based on these data and the historical landings of bay scallops in New Jersey, it is probable that a small self-seeding population exists. Assessment of reproductive cycles during 1998 showed two potential peaks in reproductive condition: one occurred during June when a maximum Gonadal-Somatic Index was recorded (24.7%) and the second was during October when a visual gonadal condition index indicated a majority of scallops in post-spawn condition. Few adult bay scallops were encountered in 1999 (n = 8) to assess reproductive cycles, but two large individuals collected during July showed a post-spawn gonadal condition. However, during both 1998 and 1999 settling juveniles (< 15 mm shell height) were only recorded in October, suggesting that recruitment to the population during these years resulted from the late summer-early fall spawn. Given the variability observed over the two years, future studies should concentrate on factors influencing inter-annual variation in abundance of this New Jersey population.
|Number of pages||8|
|Journal||Journal of Shellfish Research|
|State||Published - 1 Jan 2001|
- Argopecten irradians
- Bay scallop
- Genetic structure