Geographic Variation in Incidence of Trematode Parasites of American Plaice (Hippoglossoides platessoides) in the Northwest Atlantic

1975 ◽  
Vol 32 (4) ◽  
pp. 547-550 ◽  
Author(s):  
J. S. Scott
Keyword(s):  
Geographic Variation ◽  
Gulf Of Maine ◽  
Biological Indicators ◽  
Scotian Shelf ◽  
Northwest Atlantic ◽  
Digenetic Trematodes ◽  
Hippoglossoides Platessoides ◽  
Trematode Parasites

The digenetic trematodes Steringotrema ovacutum, Zoogonoides viciparus, Derogenes varicus, Lecithaster gihbosus, Fellodistomum furcigerum, and Stenakron vetustum were common in American plaice (Hippoglossoides platessoides) from the southern Gulf of St. Lawrence, Scotian Shelf, and northeast Gulf of Maine in the summers of 1971 and 1972. Levels of incidence of the trematodes in different areas within the region are compared. Steringotrema ovacutum, Z. viviparus, and F. furcigerum may be useful as biological indicators in plaice in the Northwest Atlantic.

Incidence of Trematode Parasites of American Plaice (Hippoglossoides platessoides) of the Scotian Shelf and Gulf of St. Lawrence in Relation to Fish Length and Food

1975 ◽  
Vol 32 (4) ◽  
pp. 479-483 ◽  
Author(s):  
J. S. Scott
Keyword(s):  
Alimentary Tract ◽  
Sea Urchins ◽  
Trematode Species ◽  
Fish Length ◽  
Intermediate Hosts ◽  
Scotian Shelf ◽  
Food Items ◽  
Digenetic Trematodes ◽  
Hippoglossoides Platessoides ◽  
Trematode Parasites

The following digenetic trematodes were found in the alimentary tract of American plaice (Hippoglossoides platessoides) from the Scotian Shelf and Gulf of St. Lawrence: Derogenes varicus, Fellodistomum furcigerum, Lecithaster gibbosus, Stenakron vetustum, Steringotrema ovacutum, Zoogonoides viviparus, Hemiurus levinseni, Otodistomum veliporum (larvae), Podocotyle atomon, Prosorhyncus squamatus.The incidence of several trematode species changed with length of fish and associated changes in the fish’s diet. Incidence of D. varicus and S. vetustum decreased with increase of host length, whereas incidence of R. ovacutum and Z. viviparus increased. Lecithaster gibbosus and S. furciger showed little change in incidence. Correlations between parasite incidence and frequency of occurrence of food items indicated that small crustaceans may be intermediate hosts for S. vetustum and D. varicus; sea urchins may be intermediate hosts for R. ovacutum and brittle stars for Z. viviparus.

scholarly journals Seasonal trends and phenology shifts in sea surface temperature on the North American northeastern continental shelf

Elem Sci Anth ◽  
2017 ◽  
Vol 5 ◽  
Author(s):  
Andrew C. Thomas ◽  
Andrew J. Pershing ◽  
Kevin D. Friedland ◽  
Janet A. Nye ◽  
Katherine E. Mills ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Continental Shelf ◽  
Sea Surface Temperature ◽  
North American ◽  
Gulf Of Maine ◽  
Sea Surface ◽  
Scotian Shelf ◽  
Seasonal Differences ◽  
Study Region ◽  
The North

The northeastern North American continental shelf from Cape Hatteras to the Scotian Shelf is a region of globally extreme positive trends in sea surface temperature (SST). Here, a 33-year (1982–2014) time series of daily satellite SST data was used to quantify and map spatial patterns in SST trends and phenology over this shelf. Strongest trends are over the Scotian Shelf (>0.6°C decade–1) and Gulf of Maine (>0.4°C decade–1) with weaker trends over the inner Mid-Atlantic Bight (~0.3°C decade–1). Winter (January–April) trends are relatively weak, and even negative in some areas; early summer (May–June) trends are positive everywhere, and later summer (July–September) trends are strongest (~1.0°C decade–1). These seasonal differences shift the phenology of many metrics of the SST cycle. The yearday on which specific temperature thresholds (8° and 12°C) are reached in spring trends earlier, most strongly over the Scotian Shelf and Gulf of Maine (~ –0.5 days year–1). Three metrics defining the warmest summer period show significant trends towards earlier summer starts, later summer ends and longer summer duration over the entire study region. Trends in start and end dates are strongest (~1 day year–1) over the Gulf of Maine and Scotian Shelf. Trends in increased summer duration are >2.0 days year–1 in parts of the Gulf of Maine. Regression analyses show that phenology trends have regionally varying links to the North Atlantic Oscillation, to local spring and summer atmospheric pressure and air temperature and to Gulf Stream position. For effective monitoring and management of dynamically heterogeneous shelf regions, the results highlight the need to quantify spatial and seasonal differences in SST trends as well as trends in SST phenology, each of which likely has implications for the ecological functioning of the shelf.

scholarly journals Diagnosing transit times on the northwestern North Atlantic continental shelf

2018 ◽  
Author(s):  
Krysten Rutherford ◽  
Katja Fennel
Keyword(s):  
North Atlantic ◽  
Gulf Of Maine ◽  
Circulation Model ◽  
Shelf Break ◽  
Genetic Connectivity ◽  
Western Boundary ◽  
Coastal Current ◽  
Scotian Shelf ◽  
Grand Banks ◽  
Transit Times

Abstract. The circulation in the northwestern North Atlantic Ocean is highly complex, characterized by the confluence of two major western boundary current systems and several shelf currents. Here we present the first comprehensive analysis of transport paths and timescales for the northwestern North Atlantic shelf, which is useful for estimating ventilation rates, describing circulation and mixing, characterizing the composition of water masses with respect to different source regions, and elucidating rates and patterns of biogeochemical processing, species dispersal and genetic connectivity. Our analysis uses dye and age tracers within a high-resolution circulation model of the region, divided into 9 sub-regions, to diagnose retention times, transport pathways, and transit times. Retention times are shortest on the Scotian Shelf (~ 3 months) where the inshore and shelf-break branches of the coastal current system result in high along-shelf transport to the southwest. Larger retention times are simulated on the Grand Banks (~ 4 months), in the Gulf of St. Lawrence (~ 12 months) and the Gulf of Maine (~ 6 months). Source water analysis shows that Scotian Shelf water is primarily comprised of waters from the Grand Banks and Gulf of St. Lawrence, with varying composition across the shelf. Contributions from the Gulf of St. Lawrence are larger at near-shore locations, whereas locations near the shelf break have larger contributions from the Grand Banks and slope waters. Waters from the deep slope have little connectivity with the shelf, because the shelf-break current inhibits transport across the shelf break. Grand Banks and Gulf of St. Lawrence waters are therefore dominant controls on biogeochemical properties, and on setting and sustaining planktonic communities on the Scotian Shelf.

scholarly journals Modeling the influence of low-salinity water inflow on winter-spring phytoplankton dynamics in the Nova Scotian Shelf–Gulf of Maine region

2008 ◽  
Vol 30 (12) ◽  
pp. 1399-1416 ◽  
Author(s):  
Rubao Ji ◽  
Cabell S. Davis ◽  
Changsheng Chen ◽  
David W. Townsend ◽  
David G. Mountain ◽  
...  
Keyword(s):  
Gulf Of Maine ◽  
Water Inflow ◽  
Phytoplankton Dynamics ◽  
Scotian Shelf ◽  
Low Salinity ◽  
Low Salinity Water ◽  
Salinity Water ◽  
Nova Scotian

Advancing an Ecosystem Approach in the Gulf of Maine

2012 ◽  
Keyword(s):  
Large Scale ◽  
Gulf Of Maine ◽  
Critical Role ◽  
Monitoring Program ◽  
Ecosystem Dynamics ◽  
Georges Bank ◽  
Scotian Shelf ◽  
Monitoring Programs ◽  
Zooplankton Dynamics ◽  
Biological Environment

<i>Abstract</i>.—Zooplankton communities perform a critical role as secondary producers in marine ecosystems. They are vulnerable to climate-induced changes in the marine environment, including temperature, stratification, and circulation, but the effects of these changes are difficult to discern without sustained ocean monitoring. The physical, chemical, and biological environment of the Gulf of Maine, including Georges Bank, is strongly influenced by inflow from the Scotian Shelf and through the Northeast Channel, and thus observations both in the Gulf of Maine and in upstream regions are necessary to understand plankton variability and change in the Gulf of Maine. Large-scale, quasi synoptic plankton surveys have been performed in the Gulf of Maine since Bigelow’s work at the beginning of the 20th century. More recently, ongoing plankton monitoring efforts include Continuous Plankton Recorder sampling in the Gulf of Maine and on the Scotian Shelf, U.S. National Marine Fisheries Service’s MARMAP (Marine Resources Monitoring, Assessment, and Prediction) and EcoMon (Ecosystem Monitoring) programs sampling the northeast U.S. Continental Shelf, including the Gulf of Maine, and Fisheries and Oceans Canada’s Atlantic Zone Monitoring Program on the Scotian Shelf and in the eastern Gulf of Maine. Here, we review and compare past and ongoing zooplankton monitoring programs in the Gulf of Maine region, including Georges Bank and the western Scotian Shelf, to facilitate retrospective analysis and broadscale synthesis of zooplankton dynamics in the Gulf of Maine. Additional sustained sampling at greater-than-monthly frequency at selected sites in the Gulf of Maine would be necessary to detect changes in phenology (i.e. seasonal timing of biological events). Sustained zooplankton sampling in critical nearshore fish habitats and in key feeding areas for upper trophic level organisms, such as marine mammals and seabirds, would yield significant insights into their dynamics. The ecosystem dynamics of the Gulf of Maine are strongly influenced by large-scale forcing and variability in upstream inflow. Improved coordination of sampling and data analysis among monitoring programs, effective data management, and use of multiple modeling approaches will all enhance the mechanistic understanding of the structure and function of the Gulf of Maine pelagic ecosystem.

Trematode Populations in the Atlantic Argentine, Argentina silus, and Their Use as Biological Indicators

1969 ◽  
Vol 26 (4) ◽  
pp. 879-891 ◽  
Author(s):  
J. S. Scott
Keyword(s):  
Biological Indicators ◽  
Reciprocal Relationship ◽  
Intermediate Hosts ◽  
Length Frequency ◽  
The West ◽  
Low Level ◽  
Mean Size ◽  
Mature Fish ◽  
Plankton Feeders ◽  
Trematode Parasites

The trematode parasites Lecithophyllum botryophorum, Derogenes various, Hemiurus levinseni, and Lampritrema nipponicum were found in Argentina silus off Nova Scotia and Newfoundland. Changes in the length-frequency distribution in the population of L. botryophorum at different times of the year reflected changes in parasite recruitment and were used tentatively to estimate the life span of the parasite.Hemiurus levinseni had a high intensity and incidence in very young fish, decreasing to a low level in mature fish; L. botryophorum had the reciprocal relationship; and D. varicus was intermediate in incidence and had a low level of intensity in fish of all sizes. These results were related to the occurrence of the intermediate hosts of the parasites and to the movement of A. silus to deeper water as it increases in size. The intensity of infestation with L. botryophorum increased from south to north. Seasonal variation in recruitment, with a peak immediately after spawning, was reflected in the intensity of infestation, mean size, and percentage of immature specimens of L. botryophorum.The young A. silus are midwater plankton feeders and the mature fish change to a diet that incorporates a high proportion of the crustacean intermediate host of L. botryophorum, probably an amphipod. There is no parasitological evidence of separate populations of A. silus in the west Atlantic.

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