This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: As climate change reshapes habitats both on land and at sea, you might go to the beach one day, only to find yourself in a place that looks nothing like you remember, around sea creatures you don't recognize. As part of the largest study of marine environmental DNA (eDNA) in Japan, researchers at the Okinawa Institute of Science and Technology (OIST) have found evidence that more than 100 species of fish may be living farther north, in cooler waters, than previous records would suggest.
These observations make it possible to track the habitable ranges of fish in more detail than ever before, which becomes especially important in the face of global warming and climate change. Published on Oct. 26, 2026, in the journal Diversity and Distributions, their results highlight how eDNA sampling can give insight into changing seascapes that will have economic, societal and environmental impacts across Japan and the world. Climate change has already fundamentally reshaped natural habitats across the globe and will continue to do so in the coming decades, with coastal marine species being particularly at risk.
One of the major effects of the rising ocean temperatures associated with climate change is a shift in the habitable range for marine species as they search for cooler waters. With an economy and culture so intertwined with the sea, Japan is poised to experience dramatic consequences of such a mass migration. Timothy Ravasi, head of the Marine Climate Change unit at OIST and senior author of the study, explains that locals are already feeling these consequences: "Fishermen across Japan are already finding differences in the types of fish they reel in compared to a few decades ago.
This is a problem because the people in these areas may not be used to buying, cooking or eating these new kinds of fish, and at the same time, they can't make the dishes that might be culturally or historically significant because those fish aren't there anymore. "And a sudden influx of new types of fish means you need new techniques, tools and knowledge to catch them, which is especially hard on small, family-based fishing businesses." But outside of local experience, understanding exactly which regions and species are affected remains a challenge. Some of the typical techniques for tracking species ranges involve citizen science observation networks, fieldwork sampling, specimen collection and optimal habitat predictions, though no technique is perfect.
Unverified data, high time and monetary costs, and prediction uncertainty abound, so marine biologists and ecologists have been looking for better ways to understand and model the habitat changes of sea creatures. This study is the first country-scale application of a new technique that aims to supplement previous data by using eDNA sampling. Just as police detectives can look for trace amounts of DNA at a crime scene to identify the culprit, scientists have recently started cataloging the tiny fragments of animal DNA present across different marine ecosystems.
While care must be taken to avoid contamination, this gives researchers a snapshot of potentially thousands of species that might be present at a particular location, with a far lower time investment than typical survey methods and with only a single bucket of seawater needed. After collection, DNA in the seawater is extracted, sequenced and compared to reference DNA structures that identify the origins of the genetic material. Discover the latest in science, tech, and space with over 100,000 subscribers who rely on Phys.org for daily insights. d research that matter—daily or weekly.
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