USA (North-East) - Ecology

The Northeast United States continental shelf (NEUS) is a highly productive ecosystem (~350-400 g C m-2 yr-1; O’Reilly and Zetlin, 1998), one of the more productive marine ecosystems noted. As such it has supported significant commercial fisheries for multiple centuries (Sissenwine et al., 1984). The sequential exploitation of NEUS is summarized in section IV: Exploitation.
In many respects the focal part of the NEUS region has been the well studied Georges Bank. Although open in an oceanic sense, Georges Bank is highly productive (Cohen et al., 1982; Fogarty and Murawski, 1998), has a high degree of nutrient recycling (Schlitz and Cohen, 1984; Franks and Chen, 2001), has a generally clockwise current pattern that concentrates nutrients and plankton (Drinkwater and Mountain, 1997; Franks and Chen, 2001; Ryan et al., 2001), exhibits a well mixed tidal current zone, is only stratified in localized areas, is influenced by both warm and cold water sources (Drinkwater and Mountain, 1997; Bisagni, 2000; Garrison et al., 2000, 2002), exhibits tropical, sub-tropical, temperate, and sub-arctic species (Collette and Klein-McPhee, 2002), is highly speciose (Link, 1999, 2002), and has a disproportionately high number of species interactions (Link, 1999, 2002), particularly for an ecosystem at this latitude. Georges Bank has remained remarkably consistent in its overall primary production, with production and standing stock biomass of phytoplankton remaining relatively stable over the past few decades, despite differences in the timing of seasonal events (O’Reilly and Zetlin, 1998; O’Reilly, pers. comm.). More broadly, the NEUS food web has a disproportionately high number of species interactions (Link, 2002). It is a highly connected food web that is dominated by bottom-up production (Link et al. 2008) and has remained remarkably consistent in amount of production over the decades. The degree of connectivity is high for most food webs and is reflective of the large size ranges across marine species life spans, the large distributional extent of marine species, the convergence of sub-tropical and sub-Arctic species, and the speciose biotic community, coupled with the mostly generalist feeding nature of these marine species.
While the various fisheries and their effects were occurring, notable changes to protected, endangered and threatened species (PETS; e.g. many marine mammals) also occurred, with many in more critical condition than 50 years ago (Waring et al., 2004). Additionally, shifts in non-targeted fauna (e.g. some benthos, some non-targeted fishes) occurred (Link and Brodziak, 2002), with some actually persisting at relatively stable levels or even increasing (Link and Brodziak, 2002; Link, 2005).