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Ecologically and economically sustainable mesopelagic fisheries

Periodic Reporting for period 1 - MEESO (Ecologically and economically sustainable mesopelagic fisheries)

Reporting period: 2019-09-01 to 2021-02-28

MEESO’s overall goal is to quantify the spatio-temporal distributions of biomass, production and ecosystem role of mesopelagic resources and to assess options to sustainably manage and govern their exploitation. To reach this goal, MEESO will create new knowledge and data on the mesopelagic community, its biodiversity, drivers of its biomass, its role in carbon sequestration, its role in the oceanic ecosystem and its interactions with the epipelagic community which includes several important commercial fish stocks. Besides applying state of the art experimental and quantitative methods, MEESO will develop and implement new acoustic and trawling technologies necessary for the knowledge and data generation in relation to this largely unknown and remote part of marine ecosystems. MEESO will apply the new knowledge and data to determine the potential of the mesopelagic biomass to be sustainably exploited for products included in the human food chain. For the first time combining leading experts in science, engineering, fisheries and governance, MEESO will develop commercial fishing and processing technologies and mapping of contaminant and nutrient contents to explore the basis for a viable fishery and creation of jobs. The new tools and technologies, as well as assessment and management roadmaps, developed in MEESO will establish the trade-offs between exploitation, sustainability and viability of the resource, and identify options for its governance.
A major objective of MEESO is to improve our ability to quantify mesopelagic components. To achieve these goals the partners have devoted most of their effort on deploying instruments (acoustic and optical) to mesopelagic depths, which enables studies at the level of individuals rather than the level of populations or aggregations. When combined with implementations of theoretical acoustic scattering models this work has allowed us to advance the scientific methods used to quantify mesopelagic biota. Combined with improvements in catch equipment and instrumentation, the basis for a sampling protocol has been laid.
Fishing technologies to optimize catch efficiency, quality and selectivity are investigated. In addition, possible commercial products from the different biomasses caught on the commercial vessels are analysed by investigating possible processing methods, contents and quality of the biomasses. Possible markets within food, feed and nutraceuticals are also determined. Key indications so far are that specialized trawls can improve the catch efficiency and selectivity, the biomass can be suitable for use in feed of food products, and early results indicate that bioactive fractions may be isolated from biomass, thus opening up a commercial potential.
MEESO will collate data from all major areas of the North Atlantic to assess the current state of mesopelagic communities with the focus on potential fishing areas and use of mesopelagic resources in the human food chain. Within the first reporting period the focus has been on collecting field data on abundance, spatial distribution, and habitat of mesopelagics using scientific cruises and fishing vessels. Post-cruise analyses of data are proceeding according to plans. Analysis of historical data shows that among four sub-polar basins in the North Atlantic the biomass of mesopelagic micronekton was higher in the western areas and peaked in the Irminger Sea. Distinct mesopelagic scattering layers were found in all basins, but daytime depth varied between basins. Investigations of contaminants show that contaminant load in mesopelagic biomass could be a concern.
A suite of models is being applied to estimate mesopelagic stocks and their resilience to harvesting and environmental change. The first 18 months have involved reviewing data on Benthosema glaciale and Maurolicus muelleri, stock assessment of existing data, and model development of population and ecosystem models. Results using TropFishR on M. muelleri data have produced new growth, mortality, and yield per recruit estimates. Results from the B. glaciale StrathSPACE population model indicate stock decline, without fishing, as a result of projected ocean warming. Runs of the NORWECOM.E2E ecosystem model show large spatial and temporal variations in biomass and growth rates of B. glaciale. The SEAPODYM-LMTL-1D model has been implemented in preparation for coupling to PICES-1D.
MEESO aims to assess the variety of economic, biological, and societal risks associated with mesopelagic fishing, including its potential economic impact, management strategies needed, and factors determining social acceptance. In the first 18 months the focus has been on the economic and technical factors determining the cost structure of fishing the mesopelagic and develop tools to assess the various risks. Our findings so far suggest that a mesopelagic fishery can potentially be commercially viable if catch rates are similar to current fisheries, solutions are found to address onboard deterioration of the catch, and biological limits are guarded well. These results will feed into assessments of market impacts, management strategies, and social acceptance in the remainder of the project.
MEESO addresses the governance of mesopelagic biodiversity, carbon and fisheries, and other human activities that could affect this zone and its ecosystem services. Over 700 marine policies are analysed, to identify gaps, synergies and implications for the mesopelagic. These results are used in combination with results from other work packages in a participatory modelling approach to analyse economic tradeoffs of a potential harvest against ecosystem services such as carbon sequestration and the provision of food to marine predators. We will deliver policy briefs for decision-makers in government, industry, and civil society to support mesopelagic governance.
The dissemination tasks, milestones and deliverables outlined in the Project Dissemination Plan (PDP) have all been achieved as planned during the first project period. This covers the PDP, the establishment of the project public web site ( and an intranet SharePoint platform, a key stakeholder and end-user client contact list, facilitation of a row of project workshops, the production of a Data Management Plan (DMP) and press releases.
To achieve its main goal MEESO will rely on state-of-the-art technology and methods and move beyond in five themes: Technology, Knowledge acquisition, Management, Governance and Capacity building. We are now setting new standards for state-of-the-art methods for measuring and quantifying mesopelagic resources by deploying submersed wideband echosounders, enabling direct quantification and measurements of individual mesopelagic organisms and their biomass in combination with theoretical scattering models. The development and deployment of larger, fine-meshed trawls for scientific surveys, as well as better methods and technology for trawl monitoring has enabled the project to move beyond some of the largest sources of uncertainty in current trawl and acoustic based methods for mesopelagic resource mapping.
MEESO's dissemination and exploitation plans aims at spreading knowledge, products and recommendations generated by MEESO to the industry, managers and other stakeholders. The approach helps to ensure that the project results and tools are embedded within end-user workflows to maximize impact.
Echoes from resolvable individual organisms at 800 m depth