Overview

Groundfish are those species that live near or on the bottom of the sea floor.  Species included in this group are Atlantic Cod, Haddock, Acadian Redfish, Winter Flounder, and many others.  Throughout the Northeast, there is a rich tradition of fishing for groundfish with fisheries dating back to the 16th century (Murawski et al. 1997).  Besides being a popular source for food, they have a strong cultural influence on the region.

Overview

Small-medium pelagic schooling fish and squid species are important to both fisheries and food webs. This group includes Atlantic herring, river herrings, Atlantic mackerel, butterfish, menhaden, and sandlance in the Northeast US. Forage fish in general can include any small pelagic plankton feeders, whether fished or unfished. Predation on forage fishes creates an important trophic link between the plankton and higher trophic levels.

Overview

Over 2000 species of benthic invertebrates, or those species whose habitat is on or associated with the seafloor, have been identified in the Northeast Large Marine Ecosystem (NE-LME). Within this group are the most important fished species in the Northeast US, including sea scallop, American lobster, eastern oyster, and blue crab among others. Benthic animals at lower trophic levels play important roles in energy transfer and nutrient recycling by consuming plankton and detritus and then serving as prey species for higher trophic levels.

Overview

Zooplankton are heterotrophic animals (prey on other plants and animals) found in the plankton, and are critical components to the functioning of marine ecosystems, serving as a link between lower trophic level production and upper trophic level consumption (Johnson et al. 2011).

Overview

Marine ecosystem productivity depends on the amount of primary production by phytoplankton, unicellular photosynthetic algae and cyanobacteria suspended in the water column that form the base of the marine food web. Measurements of the primary photosynthetic pigment, chlorophyll a (CHL), are commonly used as a proxy for phytoplankton biomass. Near-surface CHL can be measured remotely by ocean color sensors on satellites and then incorporated into integrated models to estimate primary production (PP).

Salinity

There is strong geographic variation in salinities across the northwest Atlantic. Input from fresh, cold Scotian shelf water and warmer, saltier slope water flowing through the Northeast Channel at depth result in three distinct water masses in Gulf of Maine. The saltiest and deepest is Maine Bottom Water, while the overlying Maine Intermediate Waters and Maine Surface Waters are fresher and warmer (Townsend et al. 2004).

Overview

Commercial fisheries in New England and the Mid-Atlantic have storied histories, which have been forced to come to terms with the realities of overfishing and stock collapse in the past century (Fogarty et al., 1998). Interestingly, the collapse of traditional groundfish and pelagic fisheries has coincided with a surge in the value of invertebrates, to the extent that the system is grossing the highest revenue since at least the 1970’s.

Upwelling is the upward movement of colder, nutrient-rich bottom water driven by the displacement of the surface layer. In the Mid-Atlantic, input of nutrients to the surface layer drives phytoplankton blooms, and results in high concentrations of particulate organic matter in the water column, where it is broken down through microbial respiration. Recurrent hypoxia regimes along the New Jersey coast are thought to be driven by this process (Glenn et al., 2014).

Gulf Stream & Warm Slope Water

The Gulf Stream is a major component of ocean circulation in the Northwest Atlantic. Propagation of Gulf Stream meanders and resulting eddies can create favorable conditions for high primary productivity throughout the Mid-Atlantic Bight and northwards to the Georges Bank shelf break (Townsend et al., 2006, Ryan et al., 1999).

Sea-surface temperature

Sea-surface temperatures (SST) in the U.S. Northeast Shelf Large Marine Ecosystem (NES-LME) are increasing at a faster rate than the majority of the world’s oceans, and these changes will undoubtedly affect the economy and ecology of the region over the next century.