Annex 6: Changing Ocean Impacts on the Key Forage Fish Species Arctic Cod in the Western Canadian Arctic – Linking Climate Model Projections to Subsistence Fisheries

This annex highlights the results of a study focusing on the potential impacts of ocean acidification and other climate- related stressors on marine species relevant for subsistence fisheries in the Western Arctic Bioregion. The study uses a knowledge co-production approach developed in the form of a multi-step process based on a combination of modelling and analysis tools including the Scientific Method and Indigenous Traditional Knowledge (Figure A6.1). Once all steps have been completed, uncertainties can be estimated and improvements can be made either with respect to the individual steps or to the linkages between them. The process can then be repeated, including those improvements to provide a revised assessment with reduced uncertainty ranges. The steps can be summarized as follows: (1) analyze past observed trends; (2) perform projection simulations with global and regional climate models, allowing trend estimates on 20–50 year timescales; (3) assess physiological responses and thresholds in marine species via literature research, Indigenous Traditional Knowledge, observations and focused laboratory experiments; (4) add trends, climate model projections and physiological response data to species distribution / habitat suitability and higher trophic level Ecosim/ Ecopath (see Section A6.3) models; (5) assess socio-economic impacts by applying bio-economic models, evaluating current fishery-economic activities, and discussion with communities/ community representatives; and (6) review law and governance. The latter addresses adaptation measures on global, regional and national scales. This annex describes the first application of the multi-step framework in the Western Arctic Bioregion. At this point in time all the required tools have been developed, but not all components have been adequately linked. For example, while higher resolution model projections are available for the area the habitat suitability and economic models are still driven by global climate models, the Ecopath model (see Section on The Beaufort Sea food web model) has not yet been run into the future and physiological responses are reflected in the higher trophic level models to a limited extent, if at all. In addition, while collaboration with local communities has been established (see Section on Community interests), Indigenous Traditional Knowledge has been included to a very limited extent. To summarize, this case study provides an assessment that includes all required tools, but limited linkages. It has a strong focus on uncertainty analyses and the identification of gaps in knowledge. Particular emphasis is given to the key forage fish species Arctic cod (Boreogadus saida), since climate model projections can be linked more directly to key forage species than to the (mostly) higher trophic level species harvested

Impacts of the Changing Ocean-Sea Ice System on the Key Forage Fish Arctic Cod (Boreogadus Saida) and Subsistence Fisheries in the Western Canadian Arctic—Evaluating Linked Climate, Ecosystem and Economic (CEE) Models

This study synthesizes results from observations, laboratory experiments and models to showcase how the integration of scientific methods and indigenous knowledge can improve our understanding of (a) past and projected changes in environmental conditions and marine species; (b) their effects on social and ecological systems in the respective communities; and (c) support management and planning tools for climate change adaptation and mitigation. The study links climate-ecosystem-economic (CEE) models and discusses uncertainties within those tools. The example focuses on the key forage species in the Inuvialuit Settlement Region (Western Canadian Arctic), i.e., Arctic cod (Boreogadus saida). Arctic cod can be trophically linked to sea-ice algae and pelagic primary producers and are key vectors for energy transfers from plankton to higher trophic levels (e.g., ringed seals, beluga), which are harvested by Inuit peoples. Fundamental changes in ice and ocean conditions in the region affect the marine ecosystem and fish habitat. Model simulations suggest increasing trends in oceanic phytoplankton and sea-ice algae with high interannual variability. The latter might be linked to interannual variations in Arctic cod abundance and mask trends in observations. CEE simulations incorporating physiological temperature limits data for the distribution of Arctic cod, result in an estimated 17% decrease in Arctic cod populations by the end of the century (high emission scenario), but suggest increases in abundance for other Arctic and sub-Arctic species. The Arctic cod decrease is largely caused by increased temperatures and constraints in northward migration, and could directly impact key subsistence species. Responses to acidification are still highly uncertain, but sensitivity simulations suggests an additional 1% decrease in Arctic cod populations due to pH impacts on growth and survival. Uncertainties remain with respect to detailed future changes, but general results are likely correct and in line with results from other approaches. To reduce uncertainties, higher resolution models with improved parameterizations and better understanding of the species' physiological limits are required. Arctic communities should be directly involved, receive tools and training to conduct local, unified research and food chain monitoring while decisions regarding commercial fisheries will need to be precautionary and adaptive in light of the existing uncertainties

The importance of Antarctic krill in biogeochemical cycles

Antarctic krill (Euphausia superba) are swarming, oceanic crustaceans, up to two inches long, and best known as prey for whales and penguins – but they have another important role. With their large size, high biomass and daily vertical migrations they transport and transform essential nutrients, stimulate primary productivity and influence the carbon sink. Antarctic krill are also fished by the Southern Ocean’s largest fishery. Yet how krill fishing impacts nutrient fertilisation and the carbon sink in the Southern Ocean is poorly understood. Our synthesis shows fishery management should consider the influential biogeochemical role of both adult and larval Antarctic krill

Investigations for utilizing pteropods as bioindicators of environmental change along the western Antarctic Peninsula

Pteropods are holoplanktonic gastropod molluscs found globally. Although species diversity is greater at lower latitudes, species abundance is greater at temperate and polar latitudes. Declines in pteropod populations have not only been correlated to declines of their major predators, but pteropods have also been used as bioindicators of global environmental changes such as ocean acidification. With high latitude abundances, pteropods provide significant sustenance for species such as the Atlantic salmon in the Atlantic Ocean and Pleuragramma antarcticum in the Southern Ocean. Because pteropods eat phytoplankton and other pteropods, factors that affect pteropod abundance influence many trophic levels. This dissertation explores ecological, physiological and trophodynamic relationships of pteropods when considering the influences of environmental factors observed to be altering the western Antarctic Peninsula\u27s marine ecosystem. Over the last few decades very few studies have reported the distributions of pteropods along the western Antarctic Peninsula, in particular south of the Gerlache Strait. The ecological study provided the first detailed report of the pteropods Spongiobranchaea australis and Clione antarctica along the western Antarctic Peninsula south of the Gerlache Strait, and their local distribution was correlated to the region\u27s major water masses and mesoscale water mass circulation. The physiological study of S. australis and C. antarctica yielded the first account of their metabolism, ratios of oxygen consumed to nitrogen excreted, proximate body composition, primary substrates oxidized, and enzymatic activities along the study\u27s latitudinal gradient; the first report of S. australis\u27 physiology anywhere around Antarctica. The final chapter utilized a comprehensive Ecopath with Ecosim model of the western Antarctic Peninsula\u27s marine ecosystem. The model was used to explore the trophodynamic significance of pteropods within their polar marine ecosystem as well as changes in whole ecosystem trophodynamics by employing various climate change scenarios expected to alter the Peninsula\u27s marine ecosystem over the next 40 years. The sum of these studies provides a foundation for exploring pteropods as bioindicators of environmental change along the western Antarctic Peninsula, a region currently experiencing considerable climate anomalies

The Autonomous Art of Antarctica

The Studio@620 welcomes Paul Suprenand and The Autonomous Art of Antarctica. Antarctica is a land of environmental extremes that is owned by no one… living largely in Nature’s own autonomy. The continent is home to an incredible ecosystem with ever-changing borders of land and ice, setting the canvas for natural artistic opportunities to abound, and with imagery never to be seen the same way again. To enjoy a piece of Antarctica you are invited to join us for a walk among the artistry of Paul Suprenand’s landscape and animal imagery.https://digitalcommons.usf.edu/bdj_studioat620_postcards/1069/thumbnail.jp

Episode 14: Modeling Arctic Oil Spills

Understanding the long-term effects of arctic spills like this one could be even more urgent now than ever, as oil exploration makes its way to the North Slope of Alaska (including inside the Arctic National Wildlife Refuge). C-IMAGE has developed a computer model of the entire Gulf ecosystem, so they could test how future spills would affect the region. And now, they’re applying those tools farther north

The Autonomous Art of Antarctica

The Studio@620 welcomes Paul Suprenand and The Autonomous Art of Antarctica. Antarctica is a land of environmental extremes that is owned by no one… living largely in Nature’s own autonomy. The continent is home to an incredible ecosystem with ever-changing borders of land and ice, setting the canvas for natural artistic opportunities to abound, and with imagery never to be seen the same way again. To enjoy a piece of Antarctica you are invited to join us for a walk among the artistry of Paul Suprenand’s landscape and animal imagery.https://digitalcommons.usf.edu/bdj_studioat620_postcards/1069/thumbnail.jp

Episode 14: Modeling Arctic Oil Spills

Understanding the long-term effects of arctic spills like this one could be even more urgent now than ever, as oil exploration makes its way to the North Slope of Alaska (including inside the Arctic National Wildlife Refuge). C-IMAGE has developed a computer model of the entire Gulf ecosystem, so they could test how future spills would affect the region. And now, they’re applying those tools farther north

Trophodynamic Effects of Climate Change-induced Alterations to Primary Production along the Western Antarctic Peninsula

Under climate change, alterations in primary production and concomitant changes in community dynamics are expected in many marine ecosystems. We used an Ecopath with Ecosim (EwE) marine ecosystem model of the western Antarctic Peninsula to simulate effects on the food web based on proposed changes in the primary production regime expected as a result of climate change. Scenarios for trophic modeling are based on published results from coupled high-resolution regional ocean sea-ice and ice-shelf models, which consider alterations in water circulation from westerly wind intensification, increases in circumpolar deep water upwelling, iron upwelling, and decreases in sea-ice extent. Modeling scenarios included 6, 15, and 41% increases in phytoplankton production with equivalent percentage decreases in ice algal production, and 1 scenario with 15% increase for phytoplankton with no change for ice algae. These scenarios were achieved through linear forcing functions within the EwE software. We framed ecosystem changes in terms of biomass, species diversity, mean trophic level, trophodynamics, and network metrics. Simulations revealed that in each scenario, mean trophic level increased, species diversity generally decreased, and energetic pathways were reorganized. Modeled changes in the planktonic invertebrate assemblage include changes in 2 key competitors, krill and salps. For example, model results predict declines in krill biomass with concomitant increases in salp biomass. In all scenarios that assumed a negative change in ice-algae production rates due to sea-ice habitat loss, whale, seal, and penguin populations were negatively affected. Changes in ecosystem structure in this sensitive region may serve as an indicator of changes expected in the Southern Ocean