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The major species groups, habitats and processes detailed below were selected for analysis in the assessment because they play critical roles in supporting diverse marine life. Within the species groups, specific species or habitat types were identified to represent the ecosystem of the Northwest Atlantic.
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The full report is also available for download. Please note: this PDF is 55MB. Download the full report.
This section provides important context for the assessment: acknowledgements of our contributors, an introduction to the assessment, an overview of human uses of marine resources in the region and potential next steps for conservation.
Introduction and Acknowledgements (pdf, 811 kb)
Human Uses in the Region (pdf, 2.3 mb)
Next Steps (pdf, 245 kb)
Seafloor (or benthic) habitats of the Northwest Atlantic support a wide range of organisms that live on the ocean floor. Cold water corals prefer rocky areas, while sponges and sand dollars dominate sandy zones and marine worms dominate fine-grained muds. Conservation of all seafloor habitat types is necessary to maintain their roles in fueling the food web and recycling nutrients.
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The fringing ribbons of habitats where land meets sea provide crucial support for offshore marine diversity. Hundreds of productive estuaries along the Northwest Atlantic’s coastline provide juvenile nursery and spawning grounds for fish, mollusks, seabirds and crabs. Dense beds of oysters, clams, scallops and mussels also provide a wide array of ecological services such as filtering water and protecting coastal communities from sea level rise and storm surge.
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Groundfish or “demersal” fish are characterized by their close association with the seafloor for feeding, spawning and juvenile nursery areas. As dominant predators, they influence the abundance of many other species. Fisheries for cod, haddock, halibut and hake attracted and sustained European settlement in North America some 500 years ago, and they are still economically important in many parts of the region.
Diadromous fish are species that utilize both freshwater and saltwater habitats during their life cycles. Their abundance played an important role in the settlement patterns of early colonists, and they provide an important energy link between freshwater, estuarine and marine food webs.
Small pelagic fish such as menhaden, herring and mackerel are the primary food source for top marine predators like marine mammals, sea birds and larger fish. Because of their migration patterns and life histories, some of these species transfer energy and biomass seasonally from coastal bays to offshore habitats, providing a significant link between coastal and pelagic systems.
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Marine mammals use this region primarily in spring and summer when there is an abundance of food associated with the region’s cool nutrient-rich waters. As predators, cetaceans such as dolphins, porpoises and whales are major consumers in the system.
Sea turtles utilize and link oceanic, estuarine and terrestrial ecosystems, traversing thousands of miles through productive ocean habitats to forage in seagrass meadows and bury their eggs on sandy beaches. Their highly migratory and long-lived life histories present unique challenges to their continued protection and recovery.
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Large pelagic fish such as tunas, sharks and swordfish are highly migratory fish species that live in the water column. They play a key ecological role as predators that regulate their prey communities and structure marine food webs. When they die, their carcasses add important nutrients to sea floor habitats.
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The physical characteristics of the ocean play a critical role in supporting the area’s diverse marine life. To help explain and predict distribution patterns of marine mammals, sea turtles and pelagic fish, this assessment compiled regional datasets on sea surface temperature, stratification, seafloor complexity, chlorophyll a and zooplankton biomass.
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Sea birds spend the majority of their life at sea, but return to coastal areas to breed, while shorebirds spend their lives on the coastal land edge, but forage in marine environments. Worldwide, a higher percentage of seabird species are at risk of extinction than any other bird group.
This section contains all of the species groups, specific species and habitat types to allow for cross target comparison. This section contains a lot of data, so please be patient with loading and downloading.
If you are interested in a copy of the complete report data, please contact jgreene@tnc.org.
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