State of the Atlantic Ocean synthesis report, 2022

Renée Y. Bernier, Robyn E. Jamieson, Noreen E. Kelly, Caroline Lafleur, and Andrea M. Moore (Eds.)

Abstract

Fisheries and Oceans Canada (DFO) has committed to informing Canadians on the state of Canada’s oceans and aquatic ecosystems. This technical report, prepared by DFO scientists and collaborators at Environment and Climate Change Canada (ECCC), presents a scientific synthesis of the State of the Atlantic Ocean. This report documents the status, trends, and drivers of change across nine themes representing the physical, chemical, and biological components found in Atlantic Canadian waters: physical oceanography; carbonate chemistry, pH, and dissolved oxygen; nutrients and plankton; marine macrophytes; large marine invertebrates; marine and diadromous fish; marine mammals; sea turtles; and seabirds. Summaries were based on published, peer-reviewed, and/or quality-assured/quality-controlled data and integrated over three Atlantic bioregions: the Scotian Shelf, the Gulf of St. Lawrence, and the Newfoundland and Labrador Shelves. A synthesis chapter including complementary case studies was also developed to illustrate ecosystem connections, oceanographic concepts, processes, or impacts and threats of anthropogenic stressors.

Atlantic Canadian marine ecosystems are changing, and in many cases, this change is occurring rapidly or exceeding the past known range of variability. Changes in physical and chemical oceanographic indicators, such as temperature, circulation patterns, sea ice volumes, and pH, are being driven, directly or indirectly, by climate change: in many places, Atlantic Canadian waters are now warmer, more acidic, with weaker cold intermediate layers and smaller sea ice volumes. Superimposed upon the effects of climate change are a multitude of anthropogenic drivers, such as commercial fishing, shipping, nutrient loading, invasive species, and habitat loss, that affect species across trophic levels and over different spatial and temporal scales. The combination of climate change and anthropogenic drivers across the Atlantic Canadian seascape have important consequences for marine life, altering habitat quality and food availability, shifting the distribution of species, changing abundance or biomass, and altering predator–prey interactions. These changes, however, are not uniform nor of the same magnitude across the bioregions.

The ocean is inherently dynamic; limited coverage of Atlantic Canadian waters by current monitoring programs, or spatial biases in the distribution of research effort, leaves much uncertainty around estimates of oceanographic and biological indicators. With the rise of new methods and technologies, our knowledge of Atlantic Canadian marine ecosystems continues to grow. Advances in our understanding of species’ ecology, increased availability of relevant environmental data and advanced modelling frameworks will improve our knowledge, leading to more accurate predictions of how species will likely respond to anthropogenic stressors and climate change driven alterations in their ecosystems.