Pleistocene glacial and interglacial stratigraphy of New England, Long Island, and adjacent Georges Bank and Gulf of Maine

Abstract Environmental conditions during the pelagic juvenile cod period determine their fitness to survive settlement as demersal juveniles (0-group) and recruitment. This study examines the potential growth of pelagic juvenile cod in five areas of the New England Shelf based on time series of zooplankton and ocean temperature from surveys. An individual-based model was used to estimate the temporal variation in growth of juvenile cod at each survey station based on available prey of appropriate sized copepods of Calanus finmarchicus, Pseudocalanus spp., Centropages typicus, and Centropages hamatus. Mean juvenile cod growth was low (1–7% d−1) during January–February and March–April time series across all areas, Gulf of Maine (GOM), Eastern Georges Bank, Western Georges Bank, southern New England to Middle Atlantic Bight (MAB). Growth increased significantly in May–June with the seasonal increase in copepod density and temperature generally from South to North. The 1990–1999 warm years had the highest growth of 12–14% d−1 compared with the cooler 2000–2006 years and colder 1978–1989 years of similarly lower growth of 8–11% d−1. Growth in the MAB stayed the same 13% d−1 as in 1990–1999, whereas GOM growth decreased significantly to ∼6% d−1. High prey densities during May–June 1990–1999 for Georges Bank and GOM, followed by a strong decrease in 2000–2006 may explain the decrease in growth during the same periods. While all four copepod species contributed to potential growth, C. typicus, a more southern species, could be the more important prey for juveniles in the coastal areas during all months in contrast to Pseudocalanus spp. for the larvae. Centropages typicus also is the most adaptable and likely species able to expand and thrive under warmer climatic conditions, which could be of significance to future recruitment. Age-1 recruitment for Georges Bank cod was found to be related to juvenile growth.

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Do environmental factors affect recruits per spawner anomalies of New England groundfish?

ICES Journal of Marine Science ◽

10.1016/j.icesjms.2005.04.019 ◽

2005 ◽

Vol 62 (7) ◽

pp. 1394-1407 ◽

Cited By ~ 24

Author(s):

Jon Brodziak ◽

Loretta O'Brien

Keyword(s):

Environmental Factors ◽

New England ◽

Gulf Of Maine ◽

Generalized Additive Models ◽

Additive Models ◽

Winter Flounder ◽

Water Volume ◽

Melanogrammus Aeglefinus ◽

Georges Bank ◽

Yellowtail Flounder

Abstract We evaluated the influence of environmental factors on recruits per spawner (RS) anomalies of 12 New England groundfish stocks. Nonparametric methods were used to analyse time-series of RS anomalies derived from stock-recruitment data in recent assessments. The 12 stocks occur in three geographic regions: the Gulf of Maine (cod Gadus morhua, redfish Sebastes fasciatus, winter flounder Pseudopleuronectes americanus, American plaice Hippoglossoides platessoides, witch flounder Glyptocephalus cynoglossus, and yellowtail flounder Limanda ferruginea), Georges Bank (cod, haddock Melanogrammus aeglefinus, and yellowtail flounder), and Southern New England (summer flounder Paralichthys dentatus, yellowtail flounder, and winter flounder). Randomization tests were applied to detect years when RS anomalies were unusually high or low for comparison with oceanographic conditions such as the 1998 intrusion of Labrador Subarctic Slope water into the Gulf of Maine region. Randomization methods were also used to evaluate the central tendency and dispersion of all RS anomalies across stocks. Average RS anomalies were significantly positive in 1987 across stocks and regions, indicating that environmental forcing was coherent and exceptional in that year. Responses of RS values of individual stocks to lagged and contemporaneous environmental variables such as the North Atlantic Oscillation (NAO) index, water temperature, windstress, and shelf water volume anomalies were evaluated using generalized additive models. Overall, the NAO forward-lagged by 2 years had the largest impact on RS anomalies. This apparent effect is notable because it could provide a leading indicator of RS anomalies for some commercially exploited stocks. In particular, the three primary groundfish stocks on Georges Bank (cod, haddock, and yellowtail flounder) all exhibited positive RS anomalies when the NAO2 variable was positive.

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A bioeconomic model of marine sanctuaries on Georges Bank

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f00-061 ◽

2000 ◽

Vol 57 (6) ◽

pp. 1307-1319 ◽

Cited By ~ 71

Author(s):

Daniel S Holland

Keyword(s):

New England ◽

Gulf Of Maine ◽

Georges Bank ◽

Bioeconomic Model ◽

Seasonal Movement ◽

Southern New England ◽

Modeling Methodology ◽

Spawning Stock ◽

Age Structured ◽

Groundfish Fishery

An empirically estimated fleet dynamics model for New England trawlers is integrated with spatial, age-structured models of primary groundfish species on Georges Banks, southern New England, and the Gulf of Maine. This bioeconomic model is used to explore how permanent marine sanctuaries on Georges Bank might affect catches, revenues, and spawning stock of principal groundfish species in New England. The simulations explore how the location of sanctuaries relative to major ports and their orientation relative to seasonal movement patterns of fish stocks impact their effectiveness and the distribution of benefits across groups of fishers from different ports. The simulation results also demonstrate that the impacts of sanctuaries can vary greatly across species, sometimes increasing yields for some while decreasing yields for others. While the specific results from the simulations reflect the characteristics of the New England groundfish fishery, the modeling methodology and some general conclusions are applicable to other fisheries.

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White hake, Urophycis tenuis, in the Gulf of Maine: spawning seasonality, habitat use, and growth in young of the year and relationships to the Scotian Shelf population

Canadian Journal of Zoology ◽

10.1139/z89-245 ◽

1989 ◽

Vol 67 (7) ◽

pp. 1715-1724 ◽

Cited By ~ 11

Author(s):

Michael P. Fahay ◽

Kenneth W. Able

Keyword(s):

Habitat Use ◽

New England ◽

Gulf Of Maine ◽

Early Life History ◽

Early Spring ◽

Georges Bank ◽

Scotian Shelf ◽

Southern New England ◽

Young Of The Year ◽

Pelagic Juveniles

Our interpretation of the pattern of white hake spawning seasonality, habitat use, and growth of young of the year in the Gulf of Maine – Georges Bank area is based on analyses of extensive collections of early life history stages during 1984–1987 and on comparisons with studies conducted in Canadian waters. Eggs or larvae of Urophycis tenuis were not found at any time in the study area, but pelagic juveniles were abundant in May–June and size distributions indicated a shoreward migration with growth. Recruitment to nearshore areas was detected in June–July and the rate of growth for demersal juveniles was calculated to average 1.02 mm/day in the first summer. Spawning of this species during August–September on the Scotian Shelf does not appear to influence the Gulf of Maine population but, instead, appears to involve a separate stock with a different spawning schedule. It is concluded that spawning in continental slope regions south of the Scotian Shelf, Georges Bank, and southern New England during early spring results in recruitment to nearshore areas of the Gulf of Maine and southern New England. This spawning event also provides pelagic juveniles to the Scotian Shelf prior to the onset of local spawning there.

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