scholarly journals Zooplankton abundance data from the 10m2 MOCNESS from R/V Endeavor, R/V Albatross I, and; R/V Oceanus broadscale cruises in the Gulf of Maine and Georges Bank from 1995-1999 (GB project

Author(s):  
Erich Horgan ◽  
Laurence Madin
2018 ◽  
Vol 76 (5) ◽  
pp. 163-215 ◽  
Author(s):  
Elizabeth J. Wallace ◽  
Lev B. Looney ◽  
Donglai Gong

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.


<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.


<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.


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