A new study has discovered that climate change is having an effect on how large whale species, such as the crucially threatened North Atlantic right whale, tend to utilize habitats in the warming Gulf of Maine. This shows that right whales’ use of Cape Cod Bay has moved considerably over the past two decades.
Five North Atlantic right whales feeding in an echelon formation at the water surface in Cape Cod Bay. Image Credit: Ryan Schosberg/Center for Coastal Studies, under NOAA research permit #25740-01.
The study, headed by the New England Aquarium and scientists from the University of Massachusetts Amherst, the USGS Northeast Climate Adaptation Science Center, the Center for Coastal Studies, UCLA, the National Marine Fisheries Service, and the Canadian Whale Institute has been reported in the journal Global Change Biology on June 2022.
The authors were all set to gain better knowledge about the impacts of ocean climate change on phenology, or the timing of repeated biological events like when plants flower annually. Making use of over two decades of data, the researchers quantified shifts in whale habitat use in Cape Cod Bay. This assessed trends in peak use for North Atlantic right whales, fin whales, and humpback whales.
The study discovered that peak use of Cape Cod Bay had shifted almost three weeks later for right whales and humpback whales. Variations in the timing of whale habitat use were connected to when spring starts. This has been altered due to climate change.
The study indicated that migratory marine mammals can and do adjust the timing of their habitat use in relation to climate-driven variations in their surroundings. This shows high habitat use by right whales in Cape Cod Bay from February to May, with the highest spikes in April and May.
The time of year when we are most likely to see right and humpback whales in Cape Cod Bay has changed considerably, and right whales are using the habitat much more heavily than they did 20 years ago.
Dr. Dan Pendleton, Study Lead Author and Research Scientist, Anderson Cabot Center for Ocean Life, New England Aquarium
The researchers collected data from aerial surveys performed by the Center for Coastal Studies from 1998 to 2018 and examined environmental data like sea surface temperatures and the dates that denote the beginning of spring each year.
A novel statistical technique was utilized by the team to study modifications in whale habitat use within and throughout the years. This offered deep insight into the long-term impacts of climate change on whale habitats.
Researchers performed the study in the Gulf of Maine since it is known to be one of the most quickly warming regions of the ocean, thereby making it a unique ecosystem to study biological and phenological responses to climate change, like animal migrations, as well as peaks in breeding and productivity.
In the Gulf of Maine, sea surface and bottom temperatures have raised at a rate three times faster compared to the global average for the past few decades. Altering ocean circulation and temperature — such as later fall, earlier spring, shorter winter, and longer summer — have resulted in changes in the food supply of whales across the Gulf of Maine.
One of the biggest gaps in our understanding of how climate change is shifting the yearly cycles of life in the oceans involves the largest migrating animals—whales.
Michelle Staudinger, Ecologist, US Geological Survey
Staudinger who is also the Science Coordinator at Northeast Climate Adaption Science Center, and Professor of Environmental Conservation, UMass Amherst added, “Even though they’re the largest mammals on earth, we have an incomplete understanding of where some whales go and when. This new research helps us understand how seasonal whale migration is changing, which is critical for their protection and conservation in our region.”
Furthermore, the researchers theorized that right whales might be making use of Cape Cod Bay for a long period since climate change has decreased the amount of food that is available in other Gulf of Maine habitats.
Such changes might have converted the bay into a kind of “waiting room” for right whales as richer prey resources develop in new habitats, such as the Gulf of St. Lawrence.
North Atlantic right whales are a crucially threatened species with only 336 individuals expected to be alive. The population of whales has dropped over the past 10 years as a result of human activities, like fishing gear and vessel strikes entanglements.
When large whales visit Cape Cod Bay, it is of high concern because the region is used heavily by fishermen and vessel operators. Vessel speed limits and fishing limitations in Cape Cod Bay were developed to concur with the historical peak in North Atlantic right whale habitat use.
The study demonstrates the ongoing need for government agencies to change safety measures for endangered and threatened whales, as those animals have the potential to modify their feeding and migration patterns as a reaction to climate change.
Changes in when whales use their traditional habitats has important implications for the design of protected areas. This issue is especially important as climate change continues to alter animal migrations.
Dr. Dan Pendleton, Study Lead Author and Research Scientist, Anderson Cabot Center for Ocean Life, New England Aquarium
Journal Reference:
Pendleton, D. E., et al. (2022) Decadal-scale phenology and seasonal climate drivers of migratory baleen whales in a rapidly warming marine ecosystem. Global Change Biology. doi.org/10.1111/gcb.16225.