Predictions can now Predict the location and start of marine heatwaves that can disrupt marine ecosystems. The scientists say the next step is to predict what happens to the top predators that inhabit these ecosystems.

New search Posted in Nature Communications It finds that impacts on marine predators such as sharks, tuna, and mammals vary widely and could redistribute species across international borders. Scientists predicted these shifts using species distribution models that take into account changes in temperature and other environmental conditions.

“The goal is to provide forward-looking tools to help managers think ahead about how species will redistribute during heatwaves and how they may need to proactively adjust regulations to account for these shifts,” said Heather Welsh, research associate with NOAA’s Southwest Fisheries Division. Fisheries Science Center, project scientist at UC Santa Cruz and lead author of the new research. “Predators often support important commercial fisheries, so it is important to understand how they respond to changes in the environment around them.”

Marine heatwaves have become a regular occurrence in the eastern Pacific Ocean off the West Coast in the past decade starting from Huge heat wave circa 2014 to 2016. Some studies suggest it may become more common and severe with climate change. NOAA fisheries are increasingly seeking to “Climate-Ready Fisheries“By developing management strategies that can adapt to changes in ecosystems and their inhabitants.

shift regulations

Climate-ready fisheries management decisions can include, for example, open fishing seasons, quotas, and limits that adapt to the changing distribution of species. These decisions are especially important for species such as tuna, which fleets want to catch, as well as species such as endangered sea turtles that fleets want to avoid. This approach is based on good information about how species distributions are changing.

“How do we sustainably fish and continue to protect important species in a world marked by climate change?” Welch asked. “We need to be ready to change our approach as species move and mutate. Fortunately, we can develop tools to help do this in real time.

Scientists examined the effects of four major marine heat waves in the eastern North Pacific on 14 different predators, including sea lions, bluefin tuna, mako sharks and albatrosses. The effects on distributions varied across heat waves and species. In some cases, the species’ habitats were on the verge of extinction, while in others their area had nearly doubled.

Laysan albatross at Midway Atoll. Credit: Scott Shaffer/San Jose State University

The researchers investigated how to develop an early warning system that could alert managers to such changes before or when they occur.

“We are seeing widespread changes in where and when predators go as a result of climate variability and change. Predicting potential changes before they happen is critical to proactive climate-ready management,” said Elliott Hazen, research ecologist at Southwest Fisheries. Science Center: “This is how we can protect species that need protection and ensure the sustainability of our fisheries and other ocean-based economies.”

Habitat on the move

During marine heatwaves, approximately 40 percent of great white shark habitats shifted from international waters to United States territorial waters. This can also affect other species that prey on them. Between 10 and 31 percent of the projected habitats for commercially valuable white, blue and yellowfin tuna have moved from Mexico to US waters. This shift is reflected in the extraordinary abundance of yellowfin and bluefin tuna reported by commercial and recreational fishermen in California in 2014 and 2015.

“This gives an idea of ​​the scale of changes that management may have to adapt to over relatively short periods of time,” Welch said.

In 2016, a marine heat wave along the California coast brought many humpback whales to coastal waters. They fed copious amounts of anchovies that mutated and multiplied with the unusual ocean conditions. Then a late crab season opened up in the same waters, entangling many humpback whales in the lines from the crab traps.

Since then, the fishing fleet has worked with fishery managers to make this happen Evaluate and adjust For the presence of whales off the coast before going fishing. Confirmed entanglements have decreased.

As part of the new research, the scientists developed models that track ocean temperatures and other factors to provide data Predictions in real time About how predators shift during marine heatwaves. The scientists said the forecasts could be further tailored to the needs of fisheries or other ocean managers, providing an early warning system that alerts them to environmental changes.

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