Tuesday, 23 November 2021

Hilborn gutted over flawed report


Reflection on the Minderoo Foundation’s Global Fishing Index

This Monday, the Minderoo Foundation released their 2021 Global Fishing Index report meant to give a global picture of fisheries status. I have collaborated with the Minderoo Foundation in the past, but this report is highly flawed and should be viewed sceptically. The report claims over 50% of stocks are overfished and no country gets an “A” or a “B” grade for their management efforts—just six get a “C.” Countries that have essentially eliminated overfishing and are clearly delivering near maximum benefits to their countries are graded a “C.” Why is that not an A?

The report fails to acknowledge that over much of the world, fisheries management is working; overfishing has been greatly reduced and stocks are recovering. Many countries are sustainably producing near maximum benefits from their fish stock. The message that we need to bring fisheries management, including data collection, assessment, regulation, and enforcement to all the world is needed, but not new—agency scientists, academics and NGOs have been working towards this reality for decades and the conclusions and tone of this report dismiss the work of thousands of people.

The most critical flaw in the report’s methodology is their definition of overfished. The authors call any stock whose abundance is below a level thought to produce maximum long-term yield (called the biomass that produces maximum sustainable yield, BMSY) as overfished – and estimate that roughly 50% of stocks are below BMSY, and thus “overfished.” However, if fishing effort was perfectly managed to assure maximum long-term harvest (the typical objective), stocks would fluctuate around BMSY. As a result of natural fluctuations beyond management control, stocks would be above this level half the time, but also below this level half the time.

Thus, a country that was perfectly managing its fish stocks to generate food and employment for it’s people would have half of its stocks called “overfished” by this definition. So if the report estimates that half of fish stocks are “overfished” by their definition, perhaps all world’s fisheries are being well-managed?

The report claims to have assessments of the status of 1,465 individual stocks, but many of those assessments used catch-based estimates. Catch-based estimates are a totally unreliable method of stock assessment. A major scientific journal won’t even review papers submitted to their journal that use them.

The absurdity of their methods and definitions is illustrated by the estimate of the proportion of the assessed stocks in the country that are above the accepted target. In this regard they list Bangladesh, Indonesia, India, Myanmar, Malaysia, Nigeria and Thailand as top ranked major fishing countries. This simply fails any test of veracity. These are largely countries with limited fisheries management systems and generally recognised to suffer from significant overfishing.

Their governance index comes to equally bizarre conclusions. Norway, Iceland and the U.S. score 8, but so does Indonesia and the Philippines. Chile scores even higher with a 9.

The report is full of contradictions and cherry-picking to create their overfishing narrative. For instance, they say in the introduction “there have been pockets of success where strong interventions have improved stock health.” Yet then: “globally the state of fish stocks is not improving.”

The first statement is backed by citations showing that across countries that represent half of the worlds’ fish catch (which they call mere pockets), stocks are increasing. The second statement quotes an FAO report showing that the number of overfished stocks is growing slightly. What the report misses is that fisheries management is working in fisheries encompassing half of the world’s catch, but largely unknown and likely poor in the other half. Making blanket statements about the state of global fisheries is not helpful.

Overfishing is not a global problem as the report argues, but rather a problem confined to parts of the world where fisheries management is weak. Certainly, even in the best managed places there remain some stocks that are below target levels, but in many cases these stocks are not fished at all or very slightly fished, and their poor status is due to environmental factors like climate change or terrestrial runoff.

Ray Hilborn 21 November 2021