Humans aren’t the only ones zipping along highways. As it turns out, oceans have their own transportation routes but with a distinctly different type of traveler: whales.
Known as blue corridors, these established routes guide the giant mammals during their migrations. The paths can stretch for thousands of miles, linking breeding and foraging areas. While protecting whale habitat is critical, so is preserving the routes that connect them.
Not all whales migrate, but many species do. In particular, most of the filter-feeding baleen whales are migratory. Humpback whales can travel an impressive 5,000 miles from higher-latitude feeding grounds to tropical breeding grounds, for example. Not to be outdone, one particular gray whale broke mammalian migration records when she traveled nearly 7,000 miles each way from Russia to Mexico.
Whales migrate to track resources, give birth in warmer waters and potentially shed skin cells with harmful bacteria. A recent report from the World Wide Fund for Nature (WWF) illustrates these “whale superhighways” — or migratory corridors — in vivid detail. Clearly, opportunities exist to protect and prioritize these highly-traveled areas for whales.
Sadly, protection is needed. Six of the 13 great whale species — the largest whales on earth — are classified as endangered or vulnerable. Meanwhile over a quarter of cetacean species are threatened, including whales, dolphins and porpoises.
Regulations could go a long way toward protecting these species from being harmed by human activity. Over 300,000 cetaceans are killed each year when they become entangled in fishing gear and nets, for instance. And over 640 billion kilograms of marine debris — including fishing nets, lines, buoys, floats and various other plastics — are deposited in our oceans annually. All of this lost and discarded gear poses a threat.
Ship strikes are also a leading cause of death for humpback, blue, fin and gray whales. Unfortunately, ship traffic is predicted to increase between 240 percent and 1,209 percent by 2050, exacerbating the rate of deaths. Additionally, climate change, pollution, underwater noise and overfishing in their feeding grounds, as well as habitat loss and degradation, also threaten whales.
The idea that species do better when their habitat is managed and protected as interconnected networks is known as connectivity conservation. Connectivity enhances the resilience of marine populations, helps them adapt to climate change and can promote gene flow between populations. Therefore, it is essential that these watery highways between whale habitats are maintained and safeguarded.
One way to practice connectivity conservation is through networks of marine protected areas. Less than 8 percent of the ocean is protected today. But marine protected areas provide a variety of benefits — including mitigating climate change, increasing fish catches, protecting and augmenting species diversity, and providing opportunities for tourism and wildlife viewing.
Panama, Ecuador, Colombia and Costa Rica have proposed a regional initiative to link several marine reserves that would preserve migratory whales, sea turtles, sharks and rays in one laudable example of the tactic.
Likewise, the new United Nations treaty to protect the largely unregulated high seas is a victory for conservation. This treaty paves the way to establish marine protected areas, sets standards for assessing the environmental impacts of commercial activities, and establishes a coordinated approach to deal with a patchwork of global agreements and organizations. This last component is vital for migratory marine species that swim freely between territorial waters and the high seas.
Also of note, WhaleWatch is a promising solution for ship strikes that was spearheaded by a group of scientists, managers and shipping companies. This tool predicts where endangered blue whales are likely to swim off the western U.S., which helps to mitigate ship strikes, bycatch and other threats. Whale Safe is a similar mapping tool, which collects and displays shipping and whale data for the San Francisco Bay and Santa Barbara Channel.
Speed can also be a factor in mitigating ship strikes. Since traveling below 10 knots significantly reduces risks to whales, the National Oceanic and Atmospheric Administration also makes seasonal requests for vessels to reduce their speed.
Whale conservation doesn’t just help the gentle giants of the deep. It also helps us. Whales provide a number of benefits, including that we are able to watch and experience them as they’re migrating and congregating in feeding or breeding grounds. The rapidly growing whale-watching industry is valued at nearly $2.9 billion globally.
The aquatic mammals also contribute to the ocean’s health and support the base of the marine food web: phytoplankton. In turn, this bolsters marine fisheries, which have a whopping economic impact of $325 billion annually.
Whales, through their support of phytoplankton, also represent an enormous opportunity to fight climate change. Oceans remove around 30 percent of human-emitted carbon dioxide every year, mostly due to these photosynthesizing phytoplankton. But whales also play a more direct role by uptaking large amounts of carbon in their bodies over their lifetimes. When they die, their bodies fall to the sea floor where the carbon can remain for centuries.
Whales are called an umbrella species since protecting this wide-ranging set of mammals also preserves numerous other species. These megafauna are intertwined into our history, culture and economy. And they deserve protection — whether they’re racing along their highways or resting at home.
Image credit: Silvana Palacios/Pexels
Ruscena Wiederholt is a science writer based in South Florida with a background in biology and ecology. She regularly writes pieces on climate change, sustainability and the environment. When not glued to her laptop, she likes traveling, dancing and doing anything outdoors.