Marine heat waves are extreme events of high sea surface temperature that can last for days, weeks, or months.
They can have profound impacts on marine ecosystems, affecting the physiology, behavior, and distribution of marine organisms.
However, not all species are equally affected by marine heat waves. Some may benefit from warmer waters, while others may suffer or even disappear.
How do marine heat waves affect the distribution of top ocean predators?
JOSEPH PREZIOSO/AFP via Getty Images
A new study published in Nature Communications examined the effects of four major marine heat waves in the northeastern Pacific Ocean on 14 different predators, including sea lions, bluefin tuna, mako sharks, and albatrosses.
The researchers used satellite data, animal tracking data, and species distribution models to predict how the habitat suitability of each predator changed during and after the heat waves.
The results showed that the effects of marine heat waves on the distribution of top ocean predators varied widely across species and events.
Some predators, such as elephant seals and blue whales, experienced a significant reduction in their suitable habitat area during the heat waves, sometimes to less than 10% of their normal range.
This could have negative consequences for their survival and reproduction, as they may face increased competition, predation, or human disturbance in their remaining habitat.
Other predators, such as bluefin tuna and Laysan albatrosses, saw an increase in their suitable habitat area during the heat waves, sometimes by more than 50%.
This could provide them with new opportunities for foraging and dispersal, as they may encounter new prey or avoid competitors in their expanded habitat.
Meanwhile, some predators, such as white sharks and leatherback turtles, showed little or no change in their suitable habitat area during the heat waves, indicating that they are more tolerant or adaptable to temperature fluctuations, or that they are influenced by other environmental factors besides temperature.
How can we prepare for the future impacts of marine heat waves on top ocean predators?
According to the study, it is possible to forecast the location and onset of marine heat waves using existing climate models and satellite data.
This could provide an early warning system for managers and stakeholders to anticipate and respond to the potential shifts in the distribution of top ocean predators.
The researchers suggested that fisheries management should be more flexible and adaptive to account for the dynamic changes in the availability and distribution of target and bycatch species during marine heat waves.
For example, fishing seasons, quotas, and boundaries could be adjusted in real-time based on the latest information on species movements and abundance.
This could help maintain sustainable fishing practices and protect endangered species from overexploitation or incidental capture.
The researchers also recommended that conservation efforts should be more proactive and collaborative to cope with the challenges posed by marine heat waves.
For example, protected areas, monitoring programs, and restoration projects could be expanded or relocated to match the changing habitat preferences of top ocean predators. This could help conserve their biodiversity and ecosystem services in a changing climate.
