An Ecosystem Approach for Assessment Advice and Biological Reference Points for the Gulf of Maine–Georges Bank Atlantic Herring Complex

2008 ◽  
Vol 28 (1) ◽  
pp. 247-257 ◽  
Author(s):  
W. J. Overholtz ◽  
L. D. Jacobson ◽  
J. S. Link
Keyword(s):  
Gulf Of Maine ◽  
Ecosystem Approach ◽  
Reference Points ◽  
Atlantic Herring ◽  
Georges Bank

Advancing an Ecosystem Approach in the Gulf of Maine

2012 ◽  
Keyword(s):  
Gulf Of Maine ◽  
Data Gathering ◽  
Ecosystem Approach ◽  
Bay Of Fundy ◽  
Fishing Industry ◽  
Full Potential ◽  
Georges Bank ◽  
The West ◽  
Management Guidance ◽  
Natural Foods

<i>Abstract</i>.—The Gulf of Maine (GoM) may have defined borders to some, but to the Canadian fishing industry, it carries a flow of larvae, nutrients, and other resources that help sustain the fishery from Georges Bank to the West Scotian Slope to the Bay of Fundy and all points in between. The GoM provides a source of wealth to people and communities, as well as supplying what may be one of the last natural foods on the planet. The fishing industry has been using the GoM for centuries, yet it is only recently that monitoring and data gathering has been taking place. In my opinion, we can extract much more value from the fisheries than we presently do. If the fisheries resource of the GoM is not delivering its full potential, who is ultimately responsible and accountable? In the past decade, transboundary groundfish resources from Georges Bank have been successfully managed through the Transboundary Management Guidance Committee. We can improve decision making even further in a greater ecosystem context, recognizing that decisions have to be made with the information available. An ecosystem approach to fisheries proposes a pragmatic view based on assessing the risk of not meeting agreed objectives.

scholarly journals Empirical comparisons of survey designs in acoustic surveys of Gulf of Maine-Georges Bank Atlantic herring

2006 ◽  
Vol 36 ◽  
pp. 127-144 ◽  
Author(s):  
W J Overholtz ◽  
J M Jech ◽  
W L Michaels ◽  
L D Jacobson ◽  
P J Sullivan
Keyword(s):  
Gulf Of Maine ◽  
Atlantic Herring ◽  
Georges Bank ◽  
Acoustic Surveys ◽  
Survey Designs

scholarly journals Consumption impacts by marine mammals, fish, and seabirds on the Gulf of Maine–Georges Bank Atlantic herring (Clupea harengus) complex during the years 1977–2002

2006 ◽  
Vol 64 (1) ◽  
pp. 83-96 ◽  
Author(s):  
W. J. Overholtz ◽  
J. S. Link
Keyword(s):  
Marine Mammals ◽  
Diet Composition ◽  
Gulf Of Maine ◽  
Demersal Fish ◽  
Pelagic Fish ◽  
Clupea Harengus ◽  
Sensitivity Analyses ◽  
Atlantic Herring ◽  
Georges Bank ◽  
The Impact

Abstract Overholtz, W. J. and Link, J. S. 2007. Consumption impacts by marine mammals, fish, and seabirds on the Gulf of Maine–Georges Bank Atlantic herring (Clupea harengus) complex during the years 1977–2002. ICES Journal of Marine Science, 64: 83–96. A comprehensive study of the impact of predation during the years 1977–2002 on the Gulf of Maine–Georges Bank herring complex is presented. An uncertainty approach was used to model input variables such as predator stock size, daily ration, and diet composition. Statistical distributions were constructed on the basis of available data, producing informative and uninformative inputs for estimating herring consumption within an uncertainty framework. Consumption of herring by predators tracked herring abundance closely during the study period, as this important prey species recovered following an almost complete collapse during the late 1960s and 1970s. Annual consumption of Atlantic herring by four groups of predators, demersal fish, marine mammals, large pelagic fish, and seabirds, averaged just 58 000 t in the late 1970s, increased to 123 000 t between 1986 and 1989, 290 000 t between 1990 and 1994, and 310 000 t during the years 1998–2002. Demersal fish consumed the largest proportion of this total, followed by marine mammals, large pelagic fish, and seabirds. Sensitivity analyses suggest that future emphasis should be placed on collecting time-series of diet composition data for marine mammals, large pelagic fish, and seabirds, with additional monitoring focused on the abundance of seabirds and daily rations of all groups.

Advancing an Ecosystem Approach in the Gulf of Maine

2012 ◽  
Keyword(s):  
Gulf Of Maine ◽  
Ecosystem Approach ◽  
Georges Bank ◽  
Current Signal ◽  
Eastern Side ◽  
Deep Layers ◽  
Western Side ◽  
Year 2000 ◽  
Ocean Observing ◽  
The U.S

<i>Abstract</i>.—Conventional wisdom, based on observations spanning two and a half decades (1975–2000), asserts that inflow to the Gulf of Maine (GoM) occurs primarily in two areas: inshore on the Scotian Shelf off Cape Sable, Nova Scotia and on the eastern side of the Northeast Channel (NEC). In particular, the monthly mean currents in the eastern NEC have shown persistent inflow at all depths and in all seasons, except for the occasional, but brief, reversals near the bottom (~200 m). Conversely, the flow on the western side of the NEC is normally directed out of the gulf in the surface layer and at mid-depth, consistent with the clockwise gyre over Georges Bank, but those currents do show relatively frequent reversals to inflow in the deeper layers (150–200 m), in sympathy with the flow on the eastern side. At some point between the year 2000, when the last Bedford Institute of Oceanography (BIO)/U.S. GLOBEC mooring was removed from the eastern NEC, and 2004, when a new mooring was placed there as part of the U.S. ocean observing array, a transformation occurred. The recent data, collected from a representative location in the eastern NEC, show a strongly seasonal current signal marked by persistent periods of outflow in the deep layers (>100 m), particularly in winter. This observation was first reported by Pettigrew et al. (2008), where the outflow currents occasionally extend to the surface layers as well, most notably in the winters of 2004–2005 and 2006–2007. Additional data and analyses reported here suggest that this new mode of behavior in the NEC currents could have important consequences for the GoM ecosystem. Possible causes for this “regime shift” in the NEC circulation and implications for the GoM deepwater nutrient fields and ecosystem are discussed.

scholarly journals Multi-Decadal Trends and Variability in Temperature and Salinity in the Mid-Atlantic Bight, Georges Bank, and Gulf of Maine

2018 ◽  
Vol 76 (5) ◽  
pp. 163-215 ◽  
Author(s):  
Elizabeth J. Wallace ◽  
Lev B. Looney ◽  
Donglai Gong
Keyword(s):  
River Discharge ◽  
Gulf Of Maine ◽  
Winter Season ◽  
Hudson River ◽  
The Other ◽  
Georges Bank ◽  
Spring Season ◽  
Science Center ◽  
Other Hand ◽  
Decadal Scale

Increasing attention is being placed on the regional impact of climate change. This study focuses on the decadal scale variabilities of temperature and salinity in the Mid-Atlantic Bight (MAB), Georges Bank (GB), and Gulf of Maine (GOM) from 1977 to 2016 using hydrographic survey data from the National Oceanic and Atmospheric Administration (NOAA) Northeast Fisheries Science Center. The MAB (as defined by the shelf regions from Cape Hatteras to Cape Cod) experienced warming rates of 0.57 °C per decade during the Winter/Spring season (Jan–Apr) and 0.47 °C per decade during the Fall/Winter season (Sep–Dec). The GOM and GB, on the other hand, warmed at approximately half the rate of the MAB over the same time span (1977–2016). We found that rates of warming vary on decadal time scales. From 1977 to 1999, significant temperature increases (> 0.6 °C/decade) were found in the southern regions of the MAB during the Winter/Spring season. During the same period, significant freshening (stronger than– 0.2/decade) was found in GB and the northern regions of the MAB during the Winter/Spring and Summer seasons. From 1999 to 2016, on the other hand, we found no significant trends in temperature and few significant trends in salinity with the exceptions of some northern MAB regions showing significant salting. Interannual variability in shelf salinity can in part be attributed to river discharge variability in the Hudson River and Chesapeake Bay. However, decadal scale change in shelf salinity cannot be attributed to changes in river discharge as there were no significant decadal scale changes in river outflow. Variability in along-shelf freshwater transport and saline intrusions from offshore were the likely drivers of long-term changes in MAB shelf-salinity.

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