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Fisheries need managing to keep plenty of fish in the sea

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A global study analysing how well fisheries management schemes are at preventing population decline, including data from New Zealand and Australia, finds areas where fish numbers are being managed - roughly half of the world’s fish catch - stocks remain mostly steady. But the other half is not properly assessed or managed, leaving vast areas prone to overfishing, with harvest rates three times greater than managed fisheries, and baseline fish stocks contain around half the number of fish. Since little is known about these unmanaged areas, the authors suggest sustainable fishing management tools need to be made more widely available.

Journal/conference: PNAS

DOI: 10.1073/pnas.1909726116

Organisation/s: University of Washington, USA; Fisheries New Zealand, MPI; CSIRO

Funder: All authors are involved in fisheries management or provide fisheries advice in ways that can be viewed as competing interests. Many are employed by national fisheries agencies or nongovernmental organizations that advocate for specific fisheries policies. The academic scientists have received funding from sources that include government fisheries agencies, fishing companies, and environmental nongovernmental organizations. This paper is a product of a Science for Nature and People Partnership working group at the National Center for Ecological Analysis and Synthesis, funded by The Nature Conservancy and The Wildlife Conservation Society.

Media Release

From: PNAS

Improving fish stocks with fishery management             

A study examines how improved fishery management has increased fish stock abundance. Fish stocks are vital to the global food system. However, overfishing of some stocks is contributing to decreasing abundance. To estimate the loss of potential yield from fishing pressure, Ray Hilborn and colleagues used the RAM Legacy Stock Assessment data as of 2016 that included stock data from six continents, accounting for approximately 50% of the world’s fisheries catch. Fishing pressure was significantly correlated with changes in stock abundance and management intensity of fisheries. The authors estimated that excessive fishing pressure is currently responsible for approximately 3–5% loss of potential yield from global marine fisheries where data are available. In regions where fisheries are intensively managed, legislation and fishery management changes decreased fishing pressure while stock abundance improved—in some cases, above target levels. Compared with regions with highly developed fishery management, regions with less developed fishery management had approximately three-fold greater harvest rates. The findings suggest additional management initiatives may help sustain fisheries in countries with high fishing pressure, according to the authors.


Expert Reaction

These comments have been collated by the Science Media Centre to provide a variety of expert perspectives on this issue. Feel free to use these quotes in your stories. Views expressed are the personal opinions of the experts named. They do not represent the views of the SMC or any other organisation unless specifically stated.

Francisco Blaha, International Fisheries Advisor

Knowing that something works is rather intuitive, but demonstrating that it does, requires good science to prove it, this paper is a substantial step on that complex task. The authors are all well known in their own right, and represent 12 different countries (including New Zealand) from a mixture of academic, regulatory and international development organisations.
"The authors of this paper provide evidence that the efforts of the thousands of managers, scientists, fishers, and nongovernmental organisation workers have resulted in significantly improved statuses of fisheries in much of the developed world, and increasingly in the developing world. Scientifically managed and assessed fish stocks in many places are increasing, or are already at or above the levels that will provide a sustainable long-term catch.
"The stocks of tuna under the management of the Western Central Pacific Commission are an example of good management, under the strong leadership of the Pacific Island countries with the support of the Pacific Island Fisheries Forum Agency in terms of management and compliance and the Pacific Community in terms of fisheries science and data collection/management. They have proven to the world that industrial fisheries can be managed and are not overfished. Unfortunately, this is not the case in other tuna fisheries in other oceans or in many fisheries worldwide. It continues to be a major challenge to bring fisheries science methods and sustainability to fisheries that remain largely unassessed and unmanaged.
"The picture of fisheries management worldwide is a patchy one, and varies geographically and politically. Doom generalisations that all fisheries are collapsing, while perhaps well intended, do not help to fix problems. Fisheries science, management methods and strategies, compliance monitoring and enforcement are far from perfect, but they are perfectible in time. If sufficient resources, good science, clear governance and geopolitical independence are provided to those organisations and stakeholders in charge of managing fisheries, sustainable long term catch can continue to be possible.

Last updated: 13 Jan 2020 2:07pm
Declared conflicts of interest:
I have corresponded professionally with 6 of the authors.

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