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

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.

1997 ◽  
Vol 54 (4) ◽  
pp. 907-913 ◽  
Author(s):  
D J Douglas ◽  
E R Kenchington ◽  
C J Bird ◽  
R Pocklington ◽  
B Bradford ◽  
...  

Sea scallops (Placopecten magellanicus) were fed Pseudo-nitzschia multiseries (formerly P. pungens f. multiseries, Nitzschia pungens f. multiseries) cells of high domoic acid (DA) content (4.0-6.7 pg DA cdot cell-1) for 22 days, followed by 14 days of feeding with nontoxic microalgae. DA was incorporated within 24 h by the scallops, with increased uptake after 6 days, and was concentrated in tissues in the following order: digestive gland >> remaining soft tissue >> adductor muscle. A maximum DA concentration of 3108 mu g cdot g-1 was recorded in the digestive gland, approximately 150 times the regulatory limit (20 mu g DA cdot g-1) and among the highest levels observed in bivalve molluscs; however, only trace amounts, 0.7-1.5 mu g cdot g-1, were found concomitantly in the adductor muscle. At the end of the exposure period, 50.9% of the DA that had been supplied to the scallops had been incorporated into the tissues. Concentrations in the digestive gland 14 days after termination of the toxic diet remained high, 752 mu g DA cdot g-1. Throughout the experiment, there was no sign of illness or mortality attributable to high DA loading, although the destructive sampling of animals did not allow us to assess the effects of the toxin in the longer term.


2006 ◽  
Vol 63 (5) ◽  
pp. 811-821 ◽  
Author(s):  
Bradley P. Harris ◽  
Kevin D.E. Stokesbury

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.


1983 ◽  
Vol 40 (3) ◽  
pp. 313-318 ◽  
Author(s):  
G. S. Jamieson ◽  
R. A. Chandler

Levels of Gonyaulax excavata toxin in sea scallop (Placopecten magellanicus) tissues were monitored in eastern Canada on a monthly basis between 1977 and 1981. All tissues but the adductor muscle were found to be highly toxic in Bay of Fundy scallops, with negligible toxicity observed in scallops from Georges Bank, the outer Scotian Shelf, and Northumberland Strait scallops. Level of Bay of Fundy toxicity was much higher than previously observed (maximum digestive gland toxicity: 150 000 μg/100 g in March 1978), and recent average monthly toxicity for Bay of Fundy scallop roe ranged from 184 to 286 μg/100 g. Considerable fluctuation in toxicity can occur between adjacent months, and peak toxicities in sea scallops occur during fail and winter months. Scallop roe fisheries should be permitted to be established for scallops fished from the northern part of Georges Bank and Northumberland Strait. However, a closed zone for scallop roe should be established in the Bay of Fundy and adjacent Scotian Shelf.Key words: scallop, PSP, Gonyaulax, Placopecten, mollusk


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


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.


2019 ◽  
Vol 19 (2) ◽  
pp. 293-301
Author(s):  
Luu Ngoc Thien ◽  
Nguyen Cong Thanh

Cd concentrations were determined in coastal water, sediments and soft tissues of molluscs (hakf-crenate ark (Anadara subcrenata), noble scallop (Mimachlamys nobilis) and undulating venus (Paphia undulata)), which were collected from two stations in the harvesting area in Van Don, Quang Ninh province in 2014. In this study, cadmium concentration in seawater ranged from 0.22 µg.l-1 to 1 µg.l-1 while the concentration in sediment was from 0.59 mg.kg-1 to 1.55 mg.kg-1. Cd accumulated in hakf-crenate ark (Anadara subcrenata), noble scallop (Mimachlamys nobilis) and undulating venus (Paphia undulata) ranged from 0.81 mg.kg-1 to 1.48 mg.kg-1; from 0.35 mg.kg-1 to 2.23 mg.kg-1; from 0.25 mg.kg-1 to 0.81 mg.kg-1, respectively. Research result also showed that cadmium concentration in seawater in rainy season was higher than that in dry season while a contrary trend occurred in sediment. There was a weak correlation between Cd concentration in seawater and concentration of Cd in sediment in this area (r = 0.24). The cadmium fraction in sediment in this area was contributed as follows: residual component (F5) > Mn, Fe oxyhydroxide (F3) > organic matter-bound (F4) > acid soluble (F2) > ion-changeable (F1). Cadmium levels in tissues were in the order of stomach > mantle > gill > foot. Beside, cadmium components in adductor muscle of noble scallop were lowest. Therefore, the risk level for customer when consuming undulating venus (Paphia undulata), hakf-crenate ark (Anadara subcrenata) and adductor muscle was not high. 


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