A new study published in Nature Communications from teams at the University of British Columbia and the University of Bern has explored the relationship between marine heatwaves, fish biomass and fish catches.

Using more than 25 years of data from 6,659 fisheries around the world, covering 1,246 fish and invertebrate species, the authors found that extreme ocean conditions can increase the risk of very low fish catches. Notably, that the risk can be greatest when different environmental changes occur at the same time. In particular, marine heatwave events occurring in conjunction with periods of low ocean productivity.

When temperatures are unusually high, followed by a period of low productivity, the likelihood of a very low catch increased by almost 80% in some fisheries.

The effects weren’t the same everywhere. Different species and fisheries responded differently to changing conditions, and in Australia, the strongest increases in the risk of low catches occurred when high temperatures and low productivity happened together.

This highlights an important challenge for fishers and fisheries managers: the impact of climate change isn’t necessarily about one environmental change at a time, but about how different changes interact.

The researchers suggest that better monitoring and forecasting, early warning systems and more flexible fisheries management will be important for preparing for these changes.

For Australia’s seafood sector, having better information about what is happening in the ocean, and what those changes could mean for fisheries, can help fishers make decisions earlier and adapt to changing conditions.

Across Australia’s seafood sector, fishers and aquaculture producers are already adapting to changing environmental, economic and social conditions. Sea Change Australia aims to build on this experience by bringing together research, climate information and the knowledge of people working in the sector to identify and share practical ways to adapt.

By making adaptation knowledge easier to find, understand and apply, Sea Change Australia is helping Australia’s seafood sector prepare for a future where changing ocean conditions are part of the operating environment.