trawl gear impact seabed

A new concept in trawl gear has demonstrated catch increases of fish and a reduction in the environmental impact on the seabed. Photo:  Jostein Saltskår, HI

Revolutionising Trawl Fishing: New Gear Concept Boosts Catch and Reduces Environmental Impact

In a significant breakthrough for the fishing industry, a novel trawl gear concept has demonstrated a remarkable increase of 20-40% in catch compared to conventional rock hoppers.

Beyond the impressive catch improvements, the innovative gear design also prioritises gentleness on the seabed, marking a positive stride toward a more efficient and environmentally friendly future for the sector.

On a recently concluded trip, the researchers have shown that a new trawl gear concept known as Semi-Circle Spreading Gear (SCSG) can result in increased catches, writes the Fisheries and Aquaculture Industry Research Funding (FHF)

This development stems from collaborative efforts within two key projects, namely “Development of selection systems in cod trawls – National investment 2020–2023” and “Gentle and efficient trawling for whitefish”. Executed under the auspices of the Directorate of Fisheries, these projects bring together the Institute of Marine Research, the University of Tromsø, and SINTEF Ocean.

The primary objectives of these projects are to advance selection devices for trawl fishery and diminish the ecological impact associated with trawl fishing, particularly on the seabed.

 

Less Bottom Impact, More Efficiency

The groundbreaking voyage took place aboard a commercial trawler in late November 2023, providing a platform to test a new grate with enhanced sorting capabilities and evaluate the Semi-Circle Spreading Gear (SCSG) concept. While the SCSG has undergone research trials in the past decade, this marked its debut in commercial testing.

Built in seven sections with a total length of 31.2 meters, the SCSG demonstrated a considerable reduction in bottom impact due to its hydrodynamic design, weight distribution, and insights from previous under vane gearing observations. A comprehensive analysis of the SCSG’s impact on the seabed will be conducted as part of the ongoing project “Gentle and Effective Trawling for Whitefish“, concluding in 2026.

The gear weighs only a third of a similar rockhopper gear and is designed to exert less pressure on the seabed. Thus, it is assumed to have significantly less bottom impact than a similar rockhopper gear, according to FHF.

 

50% Increase in Catch Efficiency

Directly comparing catches from double trawls equipped with traditional rockhopper gear and the SCSG revealed that the latter achieved an impressive average increase of up to 50% in fish catch. Although the exact attribution of this difference to the SCSG remains subject to interpretation, previous tests on the research vessel Helmer Hanssen indicated a 20% reduction in fish going under the fishing line compared to a standard rockhopper gear.

The SCSG’s enhanced ability to spread the trawl opening, reduce the occurrence of fish slipping beneath the fishing line, and maintain stability likely contribute to the observed surge in catches. The introduction of such groundbreaking gear signifies a pivotal milestone in the pursuit of more efficient and environmentally sustainable trawl fishing practices.

Read more about the results from the project here.

 

Source: Press Release

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