Man carrying fish
Man carrying freshly caught fish in Timor Leste. (© UN Photo/Martine Perret)

Editor’s note: A new paper in Conservation Letters offers a clearer picture of whether the ocean’s fisheries can continue to feed humanity into the future, providing a new method to help fisheries managers maintain healthy fish stocks and make the best use of the fisheries people depend on.

In this interview, Jack Kittinger, senior director of fisheries and aquaculture at Conservation International (CI) discusses the impact of the research with two of the paper’s lead authors, Andrew Rosenberg of the Union of Concerned Scientists and Elizabeth Selig of the Norwegian Institute for Water Research.

Question: Your research found that more than half of global fish stocks are overfished, or fished “too hard” to produce their maximum sustainable yield (the maximum level at which they can be routinely fished without being depleted). What were your key findings?

Andrew Rosenberg (AR): A famous fishery scientist, John Gulland, once said, “Fisheries management is an endless argument over how many fish are in the sea until all doubt is removed, but so are all the fish.” In order to manage marine fisheries as a renewable source (i.e. one that we can continue fishing from in perpetuity), it’s important to get regularly updated information on the “status” of stocks of fishable species. Managers need to know if they’re currently catching an excessive amount of a certain type of fish, what we refer to as “exceeding the productive capacity of the stock,” or, on the flip side, if a larger harvest is possible.

Elizabeth Selig (ES): Previous attempts to estimate status have given us an incomplete picture of when management was needed. They would broadly tell us that a fish stock was “fully exploited,” which generally meant it was within safe limits and could continue to be fished, or it was “overexploited,” or in poor condition. Our work shows just how far a given stock is from achieving maximum sustainable yield. This is critical information because it tells us when management can increase yields. By giving a stock a “pass” or “fail,” we are missing an opportunity to deliver greater economic and nutritional benefits to people. Given that wild-capture fisheries are often discussed as having no room for growth, this information can tell us where we could be doing better.

Q: There have been many recent assessments of global fisheries. How does the method you created more accurately assess fish stocks and in turn, how does it help managers more sustainably manage fisheries?

AR: While extensive data collection and the ability to measure the status of fisheries is happening in many…