Northeast Large Marine Ecosystems

The ocean off the coast of the Northeast United States is divided into three ecologically distinct ecosystems. 

Ecosystem-Based Management (EBM) is defined in part by geographic-specific strategies. To establish the spatial groundwork for EBM and associated integrated management plans in the Northeast Large Marine Ecosystem (NE-LME), the Northeast Integrated Ecosystem Assessment program undertook a multivariate analysis of the system’s biogeophysical characteristics, resulting in the creation of Ecological Production Units (EPU). Data used in the analyses include satellite imagery of ecosystem productivity (e.g. chlorophyll a content and primary productivity), environmental attributes such as surface and bottom temperatures and salinities, and geologic components such as bathymetry and benthic grain size.

EPUs were generated from these data through clustering analyses, resulting in the final creation of four EPUs: Mid-Atlantic Bight (MAB), Georges Bank (GB), Gulf of Maine (GoM), and Scotian Shelf (SS). While the data did not include ecological considerations beyond primary productivity, the final EPUs, in many cases, coincide with managed stocks and high effort by fisheries. However, it is recognized that the EPUs are not bound by physical barriers, and are inherently tied to the fluid nature of oceanographic and ecological variables.