Developing ecosystem-based approaches to address fisheries and climate change impacts for Newfoundland & Labrador marine ecosystems

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Aims To quantify the ecosystem dynamics of the northeast Newfoundland region through past and at present and make projections of ecosystem response to climate change. This will be undertaken by development of ecosystem models for Newfoundland & Labrador. These models can be used in combination with stock assessments to understand how ecosystem dynamics are influencing the productivity of individual stocks and estimate natural mortality - a key parameter used in stock assessments. An ecosystem modelling framework can be used to: -integrate information from stock assessments, biomass surveys, fisheries landings -inform sustainable harvesting rates across the northeast Newfoundland ecosystem -evaluate multi-species harvest control rules -set dynamic reference points to account for changing system states and transition periods -assessment of (and planning to minimize) cumulative effects -project fisheries productivity and ecosystem dynamics under to climate change Background In Newfoundland and Labrador, fisheries catches and revenues have shifted from those previously dominated by groundfish to invertebrates such as the northern shrimp and snow crab. It has been reported that invertebrate abundance has declined in recent years due to increases in temperature and predation. The contribution of environmental conditions to the collapse of cod has been debated in the literature, as has the relative contribution of fishing and natural mortality through predation by seals. Without an integrated, mechanistically connected framework that accounts for changing abundances of species and their feeding relationships and the influence of environmental conditions on stock productivity, studies evaluating changing ecosystem structure and function are limited. Climate change has already led to changes in abundance and shifts in range of marine species worldwide, and it has been shown that species in Newfoundland ecosystems have differential responses to changes in environmental conditions such as temperature, primary productivity, oxygen, and acidity. In addition to direct and indirect impacts that fishing has had on the structure and function of ecosystems, climate change adds an additional stressor and challenge in the management and prediction of fish stock productivity. There have been regional ocean model system (ROMS) developed for Newfoundland and Labrador which provide fine scale information about oceanographic currents and environmental conditions. These models can be coupled with Earth system models (ESMs) to provide climate change projections of key environmental variables, which can be used as input for Newfoundland ecosystem models to run simulations of climate change under different emissions and fishing scenarios.