scholarly journals The Influence of Temperature - Food Availability on the Shell Growth of Sea Scallop Placopecten magellanicus (Gmelin, 1791)

2016 ◽  
Vol 19 (1) ◽  
pp. 1 ◽  
Author(s):  
Adi Santoso
Keyword(s):  
Food Availability ◽  
Shell Growth ◽  
Shell Height ◽  
Culture Conditions ◽  
Outer Edge ◽  
Placopecten Magellanicus ◽  
Surface Sites ◽  
Sea Scallop ◽  
Key Words Temperature ◽  
Culture Site

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

scholarly journals Shell growth of sea scallops (Placopecten magellanicus) in the southern and northern Great South Channel, USA

2006 ◽  
Vol 63 (5) ◽  
pp. 811-821 ◽  
Author(s):  
Bradley P. Harris ◽  
Kevin D.E. Stokesbury
Keyword(s):  
Shell Growth ◽  
Shell Height ◽  
Management Strategies ◽  
Height Distribution ◽  
Placopecten Magellanicus ◽  
Geographic Scale ◽  
Sea Scallop ◽  
Asymptotic Size ◽  
The Usa ◽  
Sea Scallops

Abstract Shell growth of sea scallops in two commercially productive regions of the Great South Channel (GSC) (41°4′N 69°16′W) was studied using tag–recapture experiments. Commercial fishers captured and returned 9.7% of the 11 704 sea scallops tagged in the southern GSC study area, and 7.9% of the 18 274 sea scallops tagged in the northern GSC study area. Scallop density and shell height distribution were sampled with underwater video in the two study areas. In the southern GSC tagged scallops grew faster, reached larger asymptotic size, and had higher growth performance (Φ′) than in the northern GSC study area. Mean sea scallop density in the southern GSC was 0.117 scallops m−2 (s.e. = 0.01), and 2.601 scallops m−2 (s.e. = 0.28) in the northern GSC. Environmental factors, fishing pressure, and sea scallop density all influence shell growth on a fine geographic scale (1–100 km2) and should be considered in area-specific management strategies, such as that currently used in the USA sea scallop fishery.

Verification of Atlantic sea scallop (Placopecten magellanicus) shell growth rings by tracking cohorts in fishery closed areas

2009 ◽  
Vol 66 (5) ◽  
pp. 751-758 ◽  
Author(s):  
Deborah R. Hart ◽  
Antonie S. Chute
Keyword(s):  
Shell Growth ◽  
Shell Height ◽  
Annual Growth ◽  
Transition Matrices ◽  
Placopecten Magellanicus ◽  
Sea Scallop ◽  
Growth Increments ◽  
Repeated Sampling ◽  
The Mean ◽  
Shell Rings

We tracked the growth of large cohorts of sea scallops ( Placopecten magellanicus ) at four sites located in areas closed to scallop fishing and compared the observed growth with that inferred from rings on sea scallop shells collected at the same sites. Stochastic growth transition matrices were constructed for each site based on the shell growth increments, assuming annual ring formation. These matrices were used to predict the annual growth of the scallops, which were compared with direct observations of growth obtained by repeated sampling. Additionally, the observed growth of the scallops was used to estimate the parameters of a stochastic von Bertalanffy model for each site, which were used to estimate the mean annual growth increments as a function of starting shell height. These were compared with the mean growth increments on the shells. There was a close correspondence, in most cases, between the observed growth and the growth inferred from the shell rings, implying that the shell rings were formed annually. The lack of fishing mortality in the areas meant that there was no confounding of size-selective fishing with growth and allowed us to track cohorts longer than would otherwise have been possible.

scholarly journals Variability in the relationship between sea scallop shell height and meat weight

2009 ◽  
Vol 66 (9) ◽  
pp. 1972-1977 ◽  
Author(s):  
Brian J. Rothschild ◽  
Charles F. Adams ◽  
Christopher L. Sarro ◽  
Kevin D. E. Stokesbury
Keyword(s):  
Shell Height ◽  
Spatial And Temporal Variability ◽  
Commercial Fishing ◽  
Regression Equations ◽  
Placopecten Magellanicus ◽  
Scallop Shell ◽  
Linear Mixed Effects ◽  
Meat Weight ◽  
Sea Scallop ◽  
The Relationship

Abstract Rothschild, B. J., Adams, C. F., Sarro, C. L., and Stokesbury, K. D. E. 2009. Variability in the relationship between sea scallop shell height and meat weight. – ICES Journal of Marine Science, 66: 1972–1977. We investigated the spatial and temporal variability in the relationship between shell height and meat weight (SHMW) of the sea scallop (Placopecten magellanicus) from Georges Bank (GB) and the mid-Atlantic. Data for the study were collected collaboratively during normal commercial fishing operations. A one-way random-effects ANOVA revealed that 19–44% of the variance in MW was at the batch level. A linear mixed-effects model was used to explain the variability in SHMW regression equations across batches. There was a significant effect of month and year on the SHMW relationship for GB from June through December, and a significant effect of area and year on the SHMW relationship for the mid-Atlantic from January through May. The SHMW relationships presented reflect those of the fishery year-round rather than an estimate of the biological population at a specific point in time. Failure to include intra-annual, interannual, and regional variations in the SHMW could result in continually over- or underestimating the allowable catch in areas open to fishing for short periods. The techniques used are applicable to length–weight studies in general.

Cadmium in Sea Scallop (Placopecten magellanicus) Tissues from Clean and Contaminated Areas

1987 ◽  
Vol 44 (1) ◽  
pp. 91-98 ◽  
Author(s):  
J. F. Uthe ◽  
C. L. Chou
Keyword(s):  
Digestive Gland ◽  
Soft Tissues ◽  
Shell Height ◽  
Cadmium Concentration ◽  
Predictor Variable ◽  
Adductor Muscle ◽  
Placopecten Magellanicus ◽  
Tissue Concentrations ◽  
Sea Scallop ◽  
Sea Scallops

Over 90% of the total cadmium in the soft tissues of sea scallops (Placopecten magellanicus) was in the digestive gland with less than 1% in the adductor muscle. The amount of cadmium in the digestive gland was significantly related to shell height. Shell height was superior to age as an independent (predictor) variable due to difficulties in ageing scallops. Based on these relationships, scallops of approximately 100 mm shell height were selected to study interregional differences. Neither cadmium concentration nor burden could be used to identify contaminated areas. The ratio of digestive gland cadmium to that in the adductor muscle was lowest for scallops from Chaleur Bay, which had received substantial anthropogenic cadmium input, and for scallops that had been starved for approximately 14 mo. We suggest that the high tissue cadmium levels in scallops from Georges Bank and Browns Bank are not due to contamination from anthropogenic or natural sources but rather reflect feeding and the nutritional inadequacy of the diets. Conversely, the high levels of cadmium input to Chaleur Bay were not reflected in high tissue concentrations or burdens in scallops.

Ecophenotypic plasticity in shell growth direction of asari clam Ruditapes philippinarum

2021 ◽  
pp. 1-6
Author(s):  
Takeshi Tomiyama
Keyword(s):  
Growth Rate ◽  
Shell Growth ◽  
Shell Height ◽  
Growth Direction ◽  
Ruditapes Philippinarum ◽  
Shell Morphology ◽  
Individual Growth ◽  
Shell Size ◽  
Internal Factors ◽  
Suitable Habitats

Abstract Asari clam (or Manila clam) Ruditapes philippinarum is an important bivalve for local fisheries. This species exhibits a large variation in shell morphology, and the shell roundness tends to be greater in more unsuitable habitats. To test whether the increments in shell size parameters (length, height and width) were affected solely by environmental conditions or by internal factors such as initial shell shapes or growth rate, a field caging experiment was conducted at two different sites of unsuitable and suitable habitats in Matsukawaura Lagoon, Japan, where shell shapes of wild clams were significantly different between the habitats. In the experiment, clams were released from the two sites to the same site or to the other site and were re-collected after 3, 6 and 12 months of caging. Caged clams originating from unsuitable habitats and released to suitable habitats showed a reduction in shell height relative to shell length, while clams from suitable habitats introduced to unsuitable habitats showed marked increases in both shell height and width. Generalized linear mixed models suggested that the increase in shell height was affected largely by the release habitat (environment) whereas the increase in shell width was affected largely by the individual growth rate. These results suggest that marginal growths in shell height and width respond differently to external and internal factors of clams, resulting in plasticity in their shell shapes according to the environments to which they are translocated.

Identification of Planktonic Sea Scallop Larvae (Placopecten magellanicus) (Gmelin)

1987 ◽  
Vol 44 (7) ◽  
pp. 1361-1366 ◽  
Author(s):  
M. J. Tremblay ◽  
L. D. Meade ◽  
G. V. Hurley
Keyword(s):  
Bay Of Fundy ◽  
Placopecten Magellanicus ◽  
Sea Scallop ◽  
Bivalve Larvae ◽  
Scallop Larvae ◽  
Shape And Size

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.

Spatial and Temporal Overlap of the American Lobster (Homarus americanus) and Sea Scallop (Placopecten magellanicus) as Related to the impact of Inshore Scallop Dragging

1992 ◽  
Vol 49 (7) ◽  
pp. 1486-1492 ◽  
Author(s):  
D. L. Roddick ◽  
R. J. Miller
Keyword(s):  
Nova Scotia ◽  
Homarus Americanus ◽  
Fishing Effort ◽  
The Other ◽  
American Lobster ◽  
Placopecten Magellanicus ◽  
Time And Space ◽  
Sea Scallop ◽  
The Impact ◽  
Temporal Overlap

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.

Carbon and Nitrogen Scope for Growth as A Function of Diet in the Sea Scallop Placopecten Magellanicus

1991 ◽  
Vol 71 (2) ◽  
pp. 437-450 ◽  
Author(s):  
Jonathan Grant ◽  
Peter J. Cranford
Keyword(s):  
Nitrogen Content ◽  
Clearance Rate ◽  
Absorption Efficiency ◽  
Placopecten Magellanicus ◽  
Scope For Growth ◽  
Carbon And Nitrogen ◽  
Tissue Weight ◽  
Sea Scallop ◽  
Feeding Experiments ◽  
Carbon And Nitrogen Content

Laboratory feeding experiments with the sea scallop Placopecten magellanicus were carried out to compare scope for growth (SFG) to measured growth and determine the effect of diet on carbon and nitrogen SFG. Diets consisting of cultured phytoplankton, kelp detritus, and resuspended sediment were provided daily for 52 days (October-December). Measurements of clearance rate, absorption efficiency, respiration, O/N ratio, and carbon and nitrogen content of diets and scallop tissue were used to construct carbon and nitrogenbudgets for each diet. Growth coefficients were calculated from change in tissue weight during the study period.

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