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Main Threats

Overexploitation
The NWAE is best known for the early 1990s collapse of its once abundant Atlantic cod stocks. The depletion of this important species has changed the food web, leaving an ecosystem that is less resilient to other threats (e.g., climate change). Most cod stocks have not recovered despite more than a decade of moratoria. Fishing effort has since shifted to invertebrate species, including crab and lobster, and now there are indications that some of these populations are declining.

Bycatch
The incidental catch of non-target species in fisheries is known as bycatch and represents another significant threat to biodiversity in the NWAE. Bycatch has led to declines in non-commercial species, such as the Northern wolfish, and is inhibiting the recovery of Atlantic cod and other depleted commercial species. In 2003, up to 5,400 tonnes of cod on the southern Grand Banks – 90 per cent of the remaining population – was taken as bycatch in other fisheries. Marine mammals, seabirds and sea turtles are also frequently caught as bycatch in this ecoregion.

Habitat damage
Mobile bottom fishing, such as groundfish trawling or scallop dredging, can have major impacts on bottom habitats. Of most concern is the disturbance to spawning and nursery areas for commercial species and sensitive habitats, such as cold-water coral forests. Other fishing methods, the installation of oil and gas infrastructure, and coastal development can also have serious impacts on marine habitats.

Pollution
A variety of forms of pollution pose serious threats to biodiversity in the NWAE. For instance, the illegal dumping of bilge oil from ships kills as many as 300,000 seabirds every year off the coast of Atlantic Canada. Noise pollution from seismic surveys used in oil and gas exploration can have serious impacts on beaked whales and other species. Oil and gas production platforms can introduce oil and a range of chemicals to surrounding areas.

Invasive species
Invasive species represents a growing concern in the NWAE. Species like the green crab have been introduced through ballast water exchange and are now disrupting coastal ecosystems through predation.

Climate change
Climate change could result in widespread impacts to biodiversity in the NWAE. For instance, changes to the flow of the Labrador Current could alter water temperatures in the region and disrupt primary productivity patterns, affecting all species.

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