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Project: Sustainable multi-species harvest from the Norwegian Sea and adjacent ecosystems


Illustration photo showing mackerel catch from the cruise with ”Brennholm” and ”G.O. Sars”. Photo: Leif Nøttestad

Period 01. januar 2019 - 31. desember 2023
Financed by Norwegian Research Counsil (22.7 mill NOK) and the Norwegian Ministry of Trade, Industry and Fisheries (4.1 mill NOK)
Projects is lead by Erik Askov Mousing & Per Arneberg

The project is at the core of production of knowledge-based advice for sustainable harvest and ecosystem-based management of living marine resources.

Project summary

The project is at the core of production of knowledge-based advice for sustainable harvest and ecosystem-based management of living marine resources. The move towards an ecosystem approach in monitoring, research and advice, places great challenges in terms of data, methods and systems, while adapting to ecosystems in rapid change due to climate change. The present focus in fisheries management on achieving maximum sustainable yield of single stocks, disregards the considerable interactions that take place among commercial fish stocks and other key components of the ecosystem. A move towards more explicit handling of these interactions, and implicit trade-offs, requires more knowledge about trophic interactions and development of relevant methods. The project will contribute fundamental process understanding and development of methods to produce science output that directly support the advisory processes and accelerate the longer-term progression towards ecosystem-based management.

The project will integrate information from a large range of data sources including observations from national and international survey programs, tagging and capture-recapture data, commercial fisheries data, data from the published scientific literature and general ecological theory. A diverse suit of analytic methods will be developed and applied, ranging from simple metrics over state-of-the-art statistical modeling to fully mechanistic individual-based ecosystem models. Together, the knowledge gained will be used to develop a management strategy evaluation framework, considering relevant ecosystem interactions, in order to produce output in direct support of management decisions in Norway and within the ICES system.

Project objectives

The overall objective is to achieve an update of the knowledge required to implement multi-species and ecosystem-based fisheries management and harvest of living marine resources in a climate change perspective. The project will focus on the Norwegian sea and interactions with the North Sea and coastal ecosystems. The project is divided into three work packages: WP1 Plankton dynamics, WP2 Pelagic fish distributions, and WP3 Food web interactions, output and management advice products.

Description of work packages

WP1: Plankton dynamics

WP leader: Cecilie Thorsen Broms

Zooplankton biomasses in the Norwegian Sea has changed significantly in recent decades. Increased temperature and changes in ocean current patterns affect the distribution, abundance and population structure of zooplankton, but the underlying mechanisms causing the changes in the Norwegian Sea are poorly understood. Zooplankton production is a measure of the total production capacity of the system, and consistent low biomass levels of zooplankton may curb the production capacity up the food chain and reduce harvestable resources. Better knowledge of the changes in zooplankton dynamics is vital for understanding changes in the distribution of pelagic fish and survival of larval fish, and to better understand and asses the harvest potential and the developing harvesting industry on Calanus in the Norwegian Sea.

Objectives: In WP1, the key research questions are to expand the knowledge on 1) identifying and quantifying processes influencing the zooplankton production in the Norwegian Sea and adjacent seas with focus on identifying and quantifying bottom-up processes; 2) determine changes in zooplankton population dynamics and potential implications for the Norwegian Sea; 3) establish a protocol for annual estimation of zooplankton population size.

WP2: Pelagic fish distributions

WP leader: Aril Slotte

The distributions of several pelagic fish distributions have changed significantly in recent decades, including economically important species such as Northeast Atlantic mackerel and Norwegian spring spawning herring. These changes may typically be driven by forcing factors like changes in the environment and zooplankton distributions and dynamics. However, the migration dynamics of pelagic fish may also be influenced by other factors such as the capabilities of the fish (swimming capabilities and bioenergetics) and adaptations to migrations between spawning, feeding and wintering areas (individual and social learning). Ultimately the changes in migrations may affect availability to national and international fisheries (density, zone occupation), the quality of survey indices used in stock assessment, as well as the spatiotemporal overlap between predator and prey, thereby affecting the entire food web.

Objectives: In WP2, the key research questions are to expand the knowledge on 1) distribution of pelagic fish in relation to environmental conditions and zooplankton dynamics; 2) distribution of pelagic fish in relation the fish’s biology and ecology including adaptations to migrations and 3) predicting migration patterns and distributions of pelagic fish using mechanistic individual-based ecosystem modeling.

WP3: Food web interactions, output and management advice

WP leader: Per Wenstøp Arneberg

The aim of ecosystem-based fisheries management is to use ecosystem information to improve the management advice for fish stocks and other living marine resources. In WP3 we will use results from WP1 and WP2, as well as information from other ongoing projects, to develop a framework for ecosystem-based advice that is relevant for the management of key pelagic fish stocks in the Norwegian Sea. This will follow up on research needs that have been identified for development of ecosystem-based fisheries management in the Norwegian Sea (Huse et al., 2018, see “Related Links”). If important relationships between ecosystem components and a fish stock are known, ecosystem-based advice can be developed through explicit use of this knowledge to, for example, consider information about the influence of predators, competitors, general productivity or aspects of the physical environment. In addition, a broader perspective looking at the ecosystem as a whole will be explored asking whether there are signs of development that give reason to concern and that therefore should be considered in the stock advisory process. Thus, two parallel lines will be followed: one asking whether there are general warning signals in the ecosystem that may be important to consider in management advice processes, and another asking questions about specific relations between ecosystem components and pelagic fish stocks that are relevant for management advice.

Objective: In WP3, the key research questions are to expand the knowledge on 1) general warnings signals (environmental and/or biological) relevant for the management; 2) short-term climate forecasts and 3) development of methods for food-web and ecosystem assessments. In addition, specific trophic relationships will be investigated including 4a) mackerel predation on herring larvae; 4b) top-down processes affecting production on lower trophic levels; 4c) food competition between key pelagic stocks and 4d) potential implications of mesopelagic harvesting.