Innovative materials to reduce fuel emission and increase cod exits (MatRedEx) (39822)

Project Details


Demersal trawling for Norway lobster is economically one of the most important fisheries in Denmark and is a 500 mill. Euro fishery in EU waters. Norway lobster trawls are constructed with small meshes to retain this small-sized species efficiently and at the same time catch all the fish that are in the path of the trawl. Such a trawl design has, under the previous landing-based management system, optimised the economy in the fishery, as all marketable species and sizes were caught and all unwanted catch could be discarded back to the sea. Such an extraction practice is not legal under a fully implemented landing obligation where all catch of listed species have to be landed and subsequently deducted from the quotas of the vessels. The operational challenges of the industry are further complicated by the status of the cod stocks, which in waters like Kattegat is in a critical state where even very small catches can choke the fishery. The economic importance of cod is decreasing in several waters operated by the Danish fleet, whereas the management considerations and actions taken to avoid catches of cod is increasing. The Danish demersal trawl fleet is under an enforced landing obligation challenged due to lack of a gear design that can ensure an efficient capture of specific species and sizes in a multi-species setting. The most important species to catch efficiently without any bycatch of other species, especially cod, is Norway lobster.

The relatively small meshes in the entire lower part of the current Norway lobster trawl is important to catch Norway lobster efficiently as this species distributes low in the gear. The upper part of the trawl, however, has a small mesh overhang (roof) to ensure that no fish escape. Small mesh trawl designs have a high towing resistance (i.e. drag), which requires more power (i.e. fuel and subsequent higher CO2 emissions) to tow through the water. Re-designing this trawl to catch only Norway lobster efficiently and to avoid all fish, in particular cod, as much as possible will enable the fishers to maintain a fishery in areas like the Kattegat, and improve the economic viability in other waters while saving fuel and reducing the CO2 emissions from the sector in general.

The challenge of conducting an efficient fishery for Norway lobster under a controlled landing obligation in waters with cod stocks that may choke the fishery, will not be solved by small adjustments of the currently used trawl designs or bycatch devices. This project will develop and test radically new design concepts for both the main body of the trawl and for the codend. The new design concepts are based on known behavioural differences between fish and Norway lobster, and utilise and integrate new materials and netting constructions that modern production equipment is capable of producing today.

The aims of the MatRedEx-project are to:
1) develop and test a low-drag trawl construction that drastically reduces towing resistance, and consequently reduces fuel consumption considerably, while preserving a high catch efficiency for Norway lobster. Important material properties, such as strength, resistance towards abrasion, shrinkage and diameter, will be taken into consideration.

2) develop and test a low-flow codend that will assist the low-drag construction in reducing or eliminating cod catches. In this context, colour patterns and other visual effects are underutilised properties that can be of importance when encouraging fish to escape from the trawl and will be investigated under controlled laboratory conditions.

It is expected that the project will deliver a highly species-selective and catch-efficient Norway lobster trawl. Moreover, the underlying design principles and behavioural understanding have high relevance for other fisheries aiming at avoiding bycatch of cod or reducing fuel consumption, e.g. the mixed whitefish fishery.

DTU Aqua, National Institute of Aquatic Resources (coordinator)

Consultants in the project:
Strandby Net A/S, Denmark
Euronete Scandinavia A/S, Denmark
Danish Fishermen PO, Denmark

The project is funding by the European Maritime and Fisheries Fund (EMFF) and the Danish Fisheries Agency. 

Research area: Fisheries Technology
Research area: Marine Populations and Ecosystem Dynamics
Effective start/end date12/06/202024/09/2022


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