Bigeye and Skipjack tuna in Pacific Ocean. (© Fabien Forget/ISSF).
Editor’s note: If the tuna that Pacific Island communities have reliably fished for generations suddenly change their behavior — teeming in totally new areas of the ocean or in smaller numbers, for example — this behavioral shift doesn’t affect only the tuna. Caused by warming waters due to climate change, this shift affects everything and everyone, from other species in the marine food chain to the livelihoods of fishers all over the Pacific.
A groundbreaking conference in Australia last year raised awareness about the full picture of mass species migration in response to climate change — and what it means for human well-being. The conference’s key findings were recently published in a global review in Science. Human Nature sat down with Conservation International consultant and Pacific Islands fisheries and food security expert Johann Bell to learn more.
Question: Last year’s conference was fittingly titled “Species on the Move.” Can you explain what that means?
Answer: When we say that species are “moving,” we’re talking about two things: changes in the overall distributions of species — that is, their occurrences in places where they haven’t been observed before; and changes in their relative abundances within their known distributions.
The first of these movements is easy to detect — people observe species they have never seen before in a given place. The second can be subtler: For example, there may be little change in the overall distribution of a Southern Hemisphere coral reef fish species (because it is blocked from spreading further south due to the absence of coral reef habitat), but it becomes more abundant in the south of its distribution than in the north.
Q: You were one of the keynote speakers at the conference, and one of the authors of the global review. What was one of the review’s most important findings?
A: One of the key patterns we’ve found when studying “species on the