AQUATIC INVASIVE SPECIES Aquatic invasive species (AIS) are considered competitive organisms that establish themselves in a new environment that lacks their natural predators. This favours their rapid growth or reproduction. AIS can threaten aquatic ecosystems by occupying habitats and outcompeting native species. AIS introduction and spread can occur naturally by larvae or fragments drifting in water currents. It can also occur through human activities, including commercial shipping, recreational boating, aquaculture and fishing activities, animal and aquarium trades or by intentional introduction. Some species of ascidians (non-native tunicates) and the European green crab are the most prolific and troublesome of the non-indigenous invaders along the Atlantic Canadian coast. The negative impacts of invasive species on Atlantic Canadian Invasive European green crab. marine ecosystems include Credit: Fisheries and Oceans Canada, Erica Watson. declines in abundance and biomass of estuarine fish communities, declines in eelgrass and kelp biomass, and shifts in community structure for some benthic invertebrates. Invasive species can also have negative consequences for commercial fishing and aquaculture industries. The DFO Atlantic Zone AIS Monitoring Program uses standardized methods to monitor biofouling species. It conducts research related to the impacts and mitigation of AIS in the Atlantic.
STATUS AND TRENDS •
As of 2017, 11 marine AIS are recognized as having various levels of negative impact on Atlantic Canada’s marine ecosystems (DFO Atlantic Zone Monitoring Program).
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Warming Atlantic waters, associated with climate change, may further facilitate the establishment and subsequent impacts of AIS on Atlantic marine communities.
Vase tunicates growing on underside of floating dock in Murray Harbour, PEI. Credit: Fisheries and Oceans Canada, Erica Watson. Invasive Codium algae, Magdalen Islands, Quebec. Credit : Fisheries and Oceans Canada, C. McKindsey.
Description: Credit:
Description: Credit: CANADA’S OCEANS NOW: ATLANTIC ECOSYSTEMS
2018
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