Strategies for enhancement of natural bay scallop, Argopecten irradians irradians, populations; A case study in the Niantic River estuary, Connecticut, USA
R. Goldberg et al., Strategies for enhancement of natural bay scallop, Argopecten irradians irradians, populations; A case study in the Niantic River estuary, Connecticut, USA, AQUACUL INT, 8(2-3), 2000, pp. 139-158
We investigated strategies to enhance populations of bay scallops, Argopect
en irradians irradians (Lamarck, 1819), in a presumably recruitment-limited
natural habitat. At present, the Niantic River estuary supports only a min
or bay scallop population that is harvested recreationally. Three enhanceme
nt strategies were evaluated; (1) collection and redistribution of natural
spatfall, (2) introduction and over-wintering of hatchery-reared stock into
natural habitat to provide new spawning stock, and (3) over-wintering of h
atchery-reared stock in suspension culture for creation of mobile spawner s
anctuaries. An assessment of natural bay scallop recruitment in the Niantic
River conducted in 1997 indicated that few spat were found, they were wide
ly dispersed within the river, and peak spawning occurred in late July 1997
. Direct re-seeding was evaluated as an enhancement measure by planting hat
chery-reared scallops (congruent to 38 mm shell height) in small-scale, 100
-m(2) plots at different times and densities. Time of planting and the infe
rred predation intensity were major factors affecting survival; whereas, pl
anting density had no significant effect. Approximately 9,000 scallops (35-
45 mm shell height), broadcast within an eelgrass bed in November 1997, had
high over-winter survival and underwent gametogenesis and spawning during
1998. Of 26,000 bay scallops (congruent to 45 mm shell height) over-wintere
d in suspension culture from 1998-1999, approximately 60-80% survived, and
these scallops spawned in mobile sanctuaries, during the summer of 1999. Th
ere is good potential for using aquacultural methods for enhancement of bay
scallop populations when natural recruitment is poor and habitat and envir
onmental conditions are not limiting.