By Michel Kaiser, Professor of Fisheries Conservation and Chief Scientist at Heriot-Watt University
The health of our seas and oceans matters, not just from an environmental point of view but from an economic one, and is high on the global policy agenda.
In recent weeks the World Economic Forum has published its Global Risks Report 2022, flashing warning signs on the dashboards of governments and businesses. It cites biodiversity loss and ecosystem collapse as a top concern. In addition, life insurance giant Aviva has put pressure on businesses by saying it expects those within its global asset management portfolio to meet new targets aimed at preserving biodiversity.
But how do we ensure our seas and oceans thrive with fish, other animals and plant life when at the same time we depend on the oceans to provide food and livelihoods for billions of people? New research conducted by myself and a team of colleagues at institutions around the world underlines the importance of sustainable fisheries management. Our analysis found a mixed picture – some areas were extensively altered and fish stocks depleted by intensive fishing while others remained in a healthy condition.
We brought together data from 24 large marine regions to establish whether there is a relationship between the distribution and intensity of trawling activities and the health of the seafloor communities. We considered different habitats and various types of trawling gear.
Assessing life on the seabed, we ascribed a status score between 0 and 1, where 0 is ‘entirely’ impacted and 1 is unimpacted. Fifteen regions studies were in good condition with a status greater than 0.9, while three had a degraded status of less than 0.7. In all regions combined, we estimate that only 1.5% of seabed areas studied were in a very poor condition with a status approaching 0.
Good management of fisheries contributes to better outcomes for the broader ecosystem. Our analyses highlighted that effectively managed and sustainable fisheries are associated with regions having a seabed status of 0.95 or more.
Intensively trawled regions had low habitat status relative to others, the worst of which was the Adriatic, where fish stocks are typically over-exploited with ineffective management regimes. However, we also found that when fisheries are managed sustainably, the wider environmental impacts are considerably lower. Put simply, when we manage fish stocks well, we also take care of other environmental effects associated with trawl fisheries.
Our study demonstrates the power of global collaboration for fisheries research, and advances understanding to enable better assessment of the risks associated with trawl fisheries. The hope is that the research highlights regions needing more effective management to reduce exploitation, improve stock sustainability and seabed environmental status. Healthy seabeds means we can protect and improve biodiversity, improve ecosystem functioning for juveniles of commercially important species, and address the nature crisis our world faces.
There are examples of good practice that we can learn from. In the UK we have examples in Shetland, the Isle of Man and the English Channel of management measures which enable fish and shellfish stocks to be harvested sustainably. These measures result in fishermen spending less time at sea and hence create less disturbance on the seabed as well as lowering carbon emissions.
Professor Kaiser recently participated in the How to Feed the World without Destroying the Planet panel session as part the What Will We Eat? Summit at Expo 2020 Dubai. He was joined by other experts to examine the need to rethink how we grow, consume, and provide food for a sustainable future.
The initiative in Shetland, where this kind of management is reaping rewards, could be rolled out across the world. Commercial fishing for lobsters, crabs, scallops, queenies, whelks, clams, razors, cockles, mussels and oysters from the tideline up to six miles out from the coast is regulated by the Shetland Shellfish Management Organisation (SSMO).
Scallops are one of the most valuable catches for Scotland. This is done through the issue of licences and implementation of measures that ensure recovery of stocks and long-term sustainability. They have achieved sustainable multi-species fisheries. Management takes account of different species and sectors. There is spatial zoning, which has helped reduce conflict between fishing sectors.
An important feature of this fishery is the sense of ‘ownership’ expressed by the fishers involved with it, leading to a sense of control over their own management choices which fosters longer-term thinking about issues such as sustainability. Since animals like scallops grow quickly, leaving scallops in the sea for another year accrues more value than any interest earned in a bank account.
High quality data is required so we have a better understanding of local situations. Mapping trawl footprints requires precise information about where and when boats are in operation. In most countries this detailed data is not publicly available.
The lack of high-resolution trawl effort data or, for confidentiality reasons, where it is kept private must be addressed. The benefits to public policy at national and international levels would be immense. Management plans could be co-designed with local fishing interests to help bring together environmental, commercial and community interests.
Bottom-trawl fisheries provide about a quarter of marine catch, that is why an individually tailored, science-based management of fisheries, led by local communities, is key to preserving the marine environment, safeguarding global food supplies and protecting livelihoods for the future.
While we must protect our environment, we also must support coastal communities and human nutrition. For that, fishers need to have more control over local fishing grounds, but better data is needed to provide accurate stock assessments, records of fishing intensity and catch figures, to inform sound decision making.
If trawling and other forms of fish-catching did half the damage that their critics claim, there would be no fisheries. But there are, and then some – more than 50 per cent of the fish caught in the UK come from an area within 100km of Shetland. That is because the fisheries are well managed and sustainable. Management techniques must be flexible and collaborative, with input from industry, scientists, governments and communities.
This is an urgent issue. Maintaining “life below water” is one of the UN’s Sustainable Development Goals. By improving access to data, there is a better chance of developing specific local sustainable management plans to future-proof our fisheries, this cannot be achieved by scientists working alone, we need to draw on the knowledge and capacity of our fishing fleets to be our ‘digital eyes’ on the ocean. Only by working together can we solve some of the grand challenges that currently confront our seas.
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