MBON

The pelagic food web in the Gulf of Maine (Figure) is characteristic of the food web functioning in subarctic waters stretching across the North Atlantic from the Gulf of Maine to the Barents Sea off of northern Norway.  A critical component to the success of this food web is the copepod Calanus finmarchicus, a planktonic species that is well adapted to subarctic conditions. C. finmarchicus feeds on lipid rich phytoplankton and stores these lipids in its body to use as an energy source during fall and winter when food is in short supply.  This one species has historically been remarkably dominant as a food source for planktivorous fish, like herring and sand lance, that support many of the important fisheries, marine mammals and seabirds in the Gulf of Maine.  C. finmarchicus is also the primary food source for the endangered North Atlantic right whale, whose summer foraging habitat is determined by where this copepod species can be found in abundance. The abundance of C. finmarchicus has been on a decline in the past decade, related to increasing Gulf of Maine temperatures and shifts in currents supplying the Gulf of Maine, from rich sources originating in Canadian waters to warmer and saltier Calanus poor waters originating from the sea separating the Gulf of Maine from the Gulf Stream. C. finmarchicus is therefore a “canary in the coal mine” sentinel indicator of ecosystem change in the region.