scholarly journals Age Estimation of Sea Scallop Larvae (Placopecten magellanicus) from Daily Growth Lines on Shells

1987 ◽  
Vol 7 ◽  
pp. 123-129 ◽  
Author(s):  
G V Hurley ◽  
M J Tremblay ◽  
C Couturier
1987 ◽  
Vol 44 (7) ◽  
pp. 1361-1366 ◽  
Author(s):  
M. J. Tremblay ◽  
L. D. Meade ◽  
G. V. Hurley

Methods for the collection, processing, and identification of planktonic sea scallop larvae (Placopecten magellanicus) (Gmelin) are described. Bivalve larvae collected from the Bay of Fundy were compared with cultured P. magellanicus larvae. Sea scallop larvae collected from the plankton can be tentatively identified based on shape and size; examination of the larval hinge structure allows confirmation.


1992 ◽  
Vol 49 (8) ◽  
pp. 1597-1615 ◽  
Author(s):  
M. John Tremblay ◽  
Michael Sinclair

During autumn surveys for sea scallop larvae (Placopecten magellanicus) from 1985 to 1987, the mean abundance of sea scallop larvae on the northeast part of Georges Bank (1201–20080∙m−2) was much greater than on the southern Scotian Shelf (5–240∙m−2). Few larvae were collected between these two areas, and exchange between Georges Bank and the Scotian Shelf appears very limited. Transects across the northern flank in 1988 revealed peaks in larval abundance when on-bank temperature stratification was high. Relative larval abundance on the transects was positively related to the speed of the along-front current, suggesting physical convergence of larvae. The on-bank retention of scallop larvae on Georges Bank appears to be due to physical processes alone, since scallop larvae undertake only limited diel vertical migration. Larval exhange among adult scallop aggregations on Georges Bank (the northeast peak, the southeast part, and the South Channel) is probable, but evidence from this study is limited. The autumn production of late-stage larvae on the northern flank and northeast peak of Georges Bank is estimated to range from 120 to 1500∙m−2, which is 10–100 times greater than the density of scallops aged 1–2 yr.


1992 ◽  
Vol 49 (7) ◽  
pp. 1486-1492 ◽  
Author(s):  
D. L. Roddick ◽  
R. J. Miller

Assessment of the damage of one fishery by another requires knowledge of the overlap, in time and space, of the damaging fishing effort and the abundance of the damaged species, as well as a measure of the rate of damage. This approach was used to measure the impact of inshore scallop dragging on lobsters in Nova Scotia. Areas of reported co-occurrence of lobster and scallop grounds were surveyed by divers to determine the extent of overlap. Only 2 of 52 sites surveyed had lobsters on scallop grounds that could be dragged. Divers surveyed one site six times during 1987 and 1988 and found lobsters most abundant during August and September. Only 2% of the lobsters in the path of scallop drags were either captured or injured. The estimated value of lobsters destroyed by dragging for scallops during periods of peak lobster abundance was minor: $757 at one site and $176 at the other. Restricting dragging to periods of low lobster abundance significantly reduces this cost.


2016 ◽  
Vol 19 (1) ◽  
pp. 1 ◽  
Author(s):  
Adi Santoso

A study of the growth of the sea scallop, Placopecten magellanicus, under suspended culture conditions was carried out over a seven month period at a culture site in Graves Shoal, Mahone Bay,Nova Scotia – Canada. Scallop spat were cultivated in pearl nets at a density of 30-35 per net set at four locations corresponding to the surface (7 m) and bottom (14 m) at the outer edge and the center of the site. Shell height was measured at monthly intervals. Environmental conditions represented as temperature and food availability at the surface and bottom over the same period were also monitored. Shell Height growth rate was slightly greater at the surface than at the bottom. At the surface sites growth was greater at the outside (SUROUT) than at the center locations, but at the bottom growth was greater at the centre location (BOTIN). The only significant relationship between shell growth and temperature - food variables was chlorophyll a concentration.  Key words: temperature, food availability, shell height, sea scallop


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