scholarly journals Effects of site and season on movement frequencies and displacement patterns of juvenile sea scallops Placopecten magellanicus under natural hydrodynamic conditions in Nova Scotia, Canada

1995 ◽  
Vol 128 ◽  
pp. 225-238 ◽  
Author(s):  
AE Carsen ◽  
BG Hatcher ◽  
RE Scheibling ◽  
AW Hennigar ◽  
LH Taylor
1988 ◽  
Vol 45 (8) ◽  
pp. 1378-1386 ◽  
Author(s):  
F. C. Tan ◽  
D. Cai ◽  
D. L. Roddick

Oxygen isotope records from two sea scallops, Placopecten magellanicus, collected alive from Browns Bank, Nova Scotia, show annual cycles that closely approximate the isotopic composition predicted as a function of observed temperatures and the isotopic composition of the ambient seawater. The external growth lines coincided with the most positive δ18O values of the cycles, suggesting their formation during the period of coldest water temperatures (spring). The δ18O results indicate that the growth lines are annual events, consistent with the biological evidence.


Aquaculture ◽  
1996 ◽  
Vol 142 (1-2) ◽  
pp. 75-97 ◽  
Author(s):  
Sandra Kleinman ◽  
Bruce G. Hatcher ◽  
Robert E. Scheibling ◽  
Lawrence H. Taylor ◽  
Allan W. Hennigar

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.


<strong><em>Abstract. </em></strong>In late 1994, substantial portions of Georges Bank were closed to commercial fishing to assist with stock rebuilding. These areas were Closed Area I (CAI), located on the western portion of the bank, and Closed Area II (CAII), on the eastern portion. After about 5 years of closure, the southern portion of CAII and the central portion of CAI, having exhibited substantial increases in biomass and density of sea scallops <em>Placopecten magellanicus</em>, were reopened to scallop fishing. Before the industry was allowed entry, we conducted surveys to monitor the recovery of benthic habitat and fauna inside both areas. Sampling sites were selected in a paired station design for an inside–outside comparison representative of major habitat types in each closed area; other stations were chosen to survey the remainder of the closed areas. At each station, we examined a suite of biotic and abiotic variables ranging from substrate type to benthos to nekton. Our results suggest few differences between the inside–outside paired stations in both closed areas for nekton and benthic species composition and species richness. Fish abundance and biomass were similar inside and outside the closed areas. However, individuals of species such as skates (<em>Raja </em>spp.), haddock <em>Melanogrammus aeglefinus</em>, and flounders (Pleuronectiformes) were generally larger inside than outside the closed areas. Additionally, habitat type was important in determining the distribution, abundance, biomass, size, and feeding ecology for some of the more benthic-oriented species studied. In CAI, the differences we observed in the suite of biotic metrics are likely a result of the high diversity of habitat types, with many of the habitat types composed of higher-relief material (e.g., cobble, gravel, etc.) in the region. The seabed in the southern portion of CAII is a relatively high-energy sand habitat of low to moderate complexity and has a relatively low vulnerability to trawling and dredging, which may explain why there were less pronounced differences in abundance or biomass across habitat types in that closed area as compared to CAI. Other parts of closed areas on the northeastern shelf may exhibit more obvious changes in the same biological metrics due to the presence of more complex habitats and increased vulnerability to bottom tending fishing gear. Those differences we observed for CAI and CAII may have implications for the population dynamics of commercially valuable benthic species, yet that question remains a major challenge.


2020 ◽  
Vol 77 (5) ◽  
pp. 1992-2002
Author(s):  
Deborah R Hart ◽  
Daphne M Munroe ◽  
Joseph C Caracappa ◽  
Dale Haidvogel ◽  
Burton V Shank ◽  
...  

Abstract We examined evidence for larval spillover (increased recruitment outside the closures) of Atlantic sea scallops (Placopecten magellanicus) due to rotational closures in the Mid-Atlantic Bight using a 40-year fisheries survey time series and a larval transport model. Since the first closure of the Hudson Canyon South (HCS) area in 1998, mean recruitment in the two areas directly down-current from this closure, Elephant Trunk (ET) and Delmarva (DMV), increased significantly by factors of about 7 and 2, respectively. Stock–recruit plots indicate that low biomasses in HCS were associated with reduced mean recruitment in ET and DMV. Simulations indicate that larvae spawned in HCS often settle in the two downstream areas and that model-estimated settlement (based on gonad biomass in HCS and year-specific larval transport between the areas) is correlated with observed recruitment. This study gives strong evidence that the rotational closure of HCS has induced increased recruitment in down-current areas.


1978 ◽  
Vol 7 (2) ◽  
pp. 111-118
Author(s):  
David A. Storey ◽  
Cleve E. Willis

The Atlantic sea scallop (Placopecten magellanicus) is harvested in the waters off the coast of the northeastern United States and Canada by vessels from both countries. The Atlantic sea scallop fishery has been an important fishery in the Northeastern U.S. in recent decades. This is particularly true for New England where, during the quarter-century ending in 1976, over 10 percent of the value of all fish and shellfish landed was attributable to the harvest of sea scallops.


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