Whales and Climate Change: Big Risks to the Ocean's Biggest Species
Climate change is impacting ocean ecosystems and resulting in many challenges for a variety of marine species, including whales.
The impacts of climate change are intensifying locally and globally, significantly affecting marine life and ecosystems. We are already seeing environmental changes, including warming oceans, rising seas, ocean acidification, and an increase in the frequency and intensity of extreme weather events. The distribution patterns of many marine species are changing due to these shifting oceanographic conditions. Whales are particularly vulnerable to the effects of climate change because these effects can be magnified toward the top of the food web.
North Pacific Right Whales
North Pacific right whales are one of the rarest large whale species with an estimated 30 individuals in the eastern population. Climate change is considered one of the most significant threats facing their northernmost habitat in the Pacific. North Pacific right whales feed on zooplankton, but sea ice coverage determines where and when zooplankton can be found. Warming ocean temperatures change sea ice coverage, impacting zooplankton distribution and availability. Impacts to prey could affect the foraging behavior and success of North Pacific right whales leading to nutritional stress and diminished reproduction.
Warming ocean temperatures are causing unprecedented changes to seasonal ice coverage and thickness. Unpredictable ice patterns affect the ability of beluga whales to migrate using their typical routes and increase the potential for becoming trapped in the ice. When this happens, belugas can suffer from a lack of prey and be more vulnerable to predators. In severe cases, they can run out of areas where they can come to the surface to breathe.
Beluga foraging behavior has also changed due to altered prey distribution from warming oceans. Belugas must dive longer, deeper, and more frequently to find food. The resulting increased stress can reduce their ability to reproduce. This can make it more difficult for endangered populations, such as the Cook Inlet Beluga whale, to recover.
Southern Resident Killer Whales
There are only 73 Southern Resident killer whales remaining. This is due to several factors including limited access to their preferred prey, Chinook salmon, and high levels of contaminants from environmental pollution. Climate change has the potential to increase these two threats.
Climate change is likely to further impact salmon due to increased winter flooding, decreased stream flow, increased water temperatures, and changing ocean conditions. As their main prey, changes in salmon growth and migration patterns will reduce the Southern Resident killer whales’ ability to find sufficient food.
Warmer ocean temperatures can also elevate the concentration levels of environmental pollutants, leading to higher contaminant concentrations in Southern Resident killer whales. Elevated levels of pollutants can induce immune suppression and affect a female's ability to successfully reproduce.
Responding to Climate Change
The impacts from climate change increase and continue to affect many species and habitats. NOAA Fisheries is committed to our mission to conserve protected species in the face of these threats. With our partners, we have taken a series of steps to advance climate-focused science and management including:
Climate vulnerability assessments for marine mammals and sea turtles
Scenario planning to address uncertainties, predict impacts, and prioritize mitigation and recovery actions
Climate-smart conservation training to educate staff about implementing climate adaptation tools in their work
These activities improve our understanding of and adaptation to the impacts of climate change on protected species and their habitats while increasing climate readiness.