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Southern New England Associated Investigators: Related Web Sites: Related Time Series: Related COPEPOD Plankton Data Collections: The Northeast Fisheries Science Center (NEFSC) of the National Marine Fisheries Service (NMFS) has a longstanding monitoring program covering most of the northeast US continental shelf. The NEFSC sampling protocol divides the continental shelf into four regions (Figure 1), based on their different physical and biological characteristics, and collects hydrographic and tow data using a randomized spatial sampling technique that samples ~30 stations per region per two month period. During these surveys, zooplankton are collected using a bongo net (333 µm mesh) towed obliquely from 200 m (or the bottom) to the surface. Along the northeast US continental shelf, primary production is highest near the shore of each region and in the upwelling area of Georges Bank ("GBK", Figure 1). Lowest primary production is found in the deep-water areas of the Gulf of Maine ("GOM", Figure 1). The distribution of zooplankton biomass is similar to that of primary production, with the highest levels also found in the nearshore regions and along Georges Bank, whereas the lowest levels are found in the Gulf of Maine. Changes in the northeast US continental shelf zooplankton community have been observed in all regions. All regions in the northeast US continental shelf demonstrate a general increasing trend in total annual zooplankton biomass since the early 1980s. Changes in species composition over this period have also been observed (Kane, 2007), with smaller-bodied taxa increasing in abundance in the 1990s. There is also some evidence of a shift in seasonality for some zooplankton species (e.g. Calanus finmarchicus), with the peak abundance period beginning earlier in the season and lasting longer. Long-term SST trends at all four sites demonstrate that, al-though temperatures are currently higher than the 100-year average for each region, they are lower than the 100-year maximum seen in the 1950s. Since 1960, water temperatures in the Mid-Atlantic Bight and Southern New England have remained cooler than the 1950 maximum, but water temperatures have been slowly increasing towards this maximum in the Gulf of Maine and on Georges Bank. Water temperature is influenced by the influx of cooler, fresher water from the north, and the occurrence of low-salinity events has also increased since the early 1990s (Mountain, 2004). REFERENCES: Kane, J. 2007. Zooplankton abundance trends on Georges Bank, 1977-2004. ICES Journal of Marine Science, 64: 909-919. Mountain, D. G. 2004. Variability of the water properties in NAFO Subareas 5 and 6 during the 1990s. Journal of Northwest Atlantic Fishery Science, 34: 103-112. |