Sensitivity analysis of sea scallop (Placopecten magellanicus) larvae trajectories to hydrodynamic model configuration on Georges Bank and adjacent coastal regions

Abstract An invasive colonial tunicate (Didemnum vexillum) was initially observed on Georges Bank in 1998, and it has since spread in benthic environments on fishing grounds and areas closed to bottom-fishing. It can form dense mats on gravel substrates that are also a preferred habitat for the Atlantic sea scallop (Placopecten magellanicus), which supports one of the most valuable commercial fisheries in the United States. We used HabCam, a vessel-towed underwater imaging system, to investigate the spatial distributions of P. magellanicus and D. vexillum in a region that includes fishing grounds and an area protected from bottom-fishing. We found a negative relationship between P. magellanicus and D. vexillum, even after controlling for substrate and management status, suggesting that D. vexillum competes for habitat with P. magellanicus. We also applied the geostatistical method of universal kriging to interpolate the distribution of D. vexllium based on the covariables gravel, depth and area. Our results indicate that D. vexillum is more common in areas open to fishing than in the areas closed to fishing, even taking bottom substrate effects into account. Didemnum vexillum appears to have spread over portions of the northern edge of Georges Bank. This research evaluates potential fish and invertebrate habitat degradation caused by an invasive species.

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Impact of the invasive colonial tunicate Didemnum vexillum on the recruitment of the bay scallop (Argopecten irradians irradians) and implications for recruitment of the sea scallop (Placopecten magellanicus) on Georges Bank

Aquatic Invasions ◽

10.3391/ai.2009.4.1.21 ◽

2009 ◽

Vol 4 (1) ◽

pp. 207-211 ◽

Cited By ~ 13

Author(s):

James Morris

Keyword(s):

Argopecten Irradians ◽

Georges Bank ◽

Placopecten Magellanicus ◽

Didemnum Vexillum ◽

Sea Scallop ◽

Bay Scallop

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Paralytic Shellfish Poison in Sea Scallops (Placopecten magellanicus) in the West Atlantic

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f83-046 ◽

1983 ◽

Vol 40 (3) ◽

pp. 313-318 ◽

Cited By ~ 19

Author(s):

G. S. Jamieson ◽

R. A. Chandler

Keyword(s):

Adductor Muscle ◽

Bay Of Fundy ◽

Georges Bank ◽

Placopecten Magellanicus ◽

Eastern Canada ◽

The West ◽

Monthly Basis ◽

Sea Scallop ◽

Paralytic Shellfish ◽

Sea Scallops

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

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Spatial and Parent-Age Analysis of Stock–Recruitment in the Georges Bank Sea Scallop (Placopecten magellanicus) Population

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f93-065 ◽

1993 ◽

Vol 50 (3) ◽

pp. 564-574 ◽

Cited By ~ 21

Author(s):

Richard McGarvey ◽

Fredric M. Serchuk ◽

Ian A. McLaren

Keyword(s):

Time Series ◽

Egg Production ◽

Positive Relationship ◽

Georges Bank ◽

Placopecten Magellanicus ◽

Sea Scallop ◽

Large Numbers ◽

Stock Recruitment ◽

Northern Edge ◽

Yield Per Recruit

Reproductive interaction between and within subpopulations on Georges Bank was investigated employing annual sampling surveys of sea scallop (Placopecten magellanicus) abundance available from 1977 to 1988. Time series of recruitment and, together with size-specific fecundity, total yearly egg production were constructed for Georges Bank and all subregions to generate a spatial stock–recruitment analysis. Recruitment is correlated with egg production within the population on the Northern Edge and Northeast Peak which may imply that it is reproductively self-sustaining. Stock–recruitment correlations increased when the eggs of scallops age 3 and 4 were excluded from the stock measure of total egg production. This increase in correlation occurred in every subregion where there was evidence of a positive relationship between eggs and recruits, most strongly for the Northern Edge and Northeast Peak. This is consistent with the hypothesis that older scallops (ages 5 +) are the principle contributors to recruitment. Presently, the fishery begins removing large numbers at age 3.25. Previous yield per recruit analyses have predicted higher yields if age of first capture were raised. These correlations may suggest that the same policy could also result in higher recruitment.

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