How Climate-driven Ocean Changes Affect Right Whale Populations

Featured Image Caption: Right whale populations are fluctuating as ocean regimes shift (Image Source: “Mother’s first calf” by FWC Fish and Wildlife Research Institute, licenses under CC BY-NC-ND 2.0).

Reference: Meyer-Gutbrod, E., Greene, C., Davies, K., & Johns, D. (2021). Ocean Regime Shift is Driving Collapse of the North Atlantic Right Whale Population. Oceanography, 34(3), 22-31. https://doi.org/10.5670/oceanog.2021.308

Climate change is something all living creatures are living through right now. In the past two decades, the changes in climate have not only been affecting us in terrestrial ecosystems, but they have also been shifting the balance of underwater ecosystems. For us, this climate change has been evident through shifts in temperature and precipitation. For marine mammals, it’s been evident through rising temperatures, yes, but also through chemical and nutritional changes in the water.

In their paper, Meyer-Gutbrod, Greene, Davies, and Johns explored how climate-driven changes have been affecting the North Atlantic right whale populations. Right whales, also known as black whales, got their name from being the “right” whales to hunt centuries ago, since they used to float after being killed. Coming close to extinction before the 1935 international prohibition on whaling, the North American right whale populations have never recovered up to pre-hunting status, but they have improved through the decades.

An Optimistic Past

From 2000 to 2009, scientists were confident about the future of the North Atlantic right whale population. They were sure that, in less than two decades, the population could turn the tide and double its size. The Gulf of Maine was receiving cool waters and food availability in the summers was at an all-time high. Whales were safer, as policies protected the areas they were inhabiting, reducing the number of strikes and entanglements per year. Using long-term physical and ecological data presented by various authors and organizations, Meyer-Gutbrod et al. analyzed the state of the right whale population in the Gulf of Maine and presented how all of the previously described conditions were observed to lead to more births per year. Nonetheless, as time progressed, these circumstances started to change, and by 2010, the population’s odds had shifted.

Map of the Gulf of Maine, as captured through Google Earth (Image Source: Google Earth screenshot, licensed under fair use).
A Complicated Present

It may sound cliché, but things were better in the past for the North Atlantic right whale population. In the Gulf of Maine, the researchers observed that climate changes have affected the food web greatly. From 2010 to 2019, the Gulf of Maine started receiving warmer waters, and food availability in the summers decreased to the point where the population couldn’t sustain itself anymore. Therefore, these right whales were forced to leave the traditional locations they used to inhabit. As their grounds shifted, the present policies became inefficient, and the number of strikes and entanglements in the area increased. These conditions led to higher mortality rates and fewer births per year. As of 2017, scientists estimate that the species will go extinct in less than a century.

What Awaits Us: A Pessimistic or a Promising Future?

The current and worsening climate conditions are the biggest threats that the North Atlantic right whale population is facing right now. Anthropogenic climate change is believed to be behind the changes in the ocean, and these changes cannot be taken back. Researchers could observe projections that may suggest how this population will move as they react to a warming ocean. Regardless of how accurate scientists get at predicting their moves, if ocean conditions keep changing, North Atlantic right whales will continue to surprise biologists with habitat shifts and behavioral changes.

You can help by pushing for more awareness and fighting for policies that protect the new areas where North Atlantic right whales are found, now or in the future. The current climate change in the Gulf of Maine would be hard, if not impossible, to revert, but we can all take steps towards a more sustainable future, where mitigation and climate action could stop these changes from progressing and putting greater stress over this valuable population of right whales.

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Andrea Valcarcel

Having graduated with a Bachelor of Science degree in Animal Biology from Thompson Rivers University (BC, Canada), I am currently working as a marine mammal specialist and marine resource analyst in the Dominican Republic while also being an MSc candidate in Ecology and Environmental Sciences. My research so far has been mostly focused on corals and marine mammals, but I'm not completely set on being focused on marine sciences for the rest of my life. When not monitoring marine ecosystems, you can find me training therapy dogs and reading YA and fantasy novels. Twitter: @andreavalcar

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