Blue Whales Won’t Rebound Unless We Prevent Collisions With Ships
Blue whales are majestic, beautiful and utterly amazing — and we almost lost them. That’s why numerous treaties and protections have been passed to help blue whales and their relatives survive, including strict restrictions on whaling, an activity which is closely monitored by the International Whaling Commission. Given these protections, researchers had been anticipating that the blue whale population would start to recover, but, mysteriously, that hasn’t been the case. Instead, whale populations are staying low, and that’s worrying, because once populations dip below a certain number, species conservation can be extremely difficult.
Researchers wanted to find out what was happening, and what they found was troubling: Though greater protections should be in theory be making it easier for whales out there in the world’s oceans, ship strikes are having an unexpectedly large impact on these gracious cetaceans. These scientists have been tracking 171 North Pacific whales over the last 15 years, providing an unprecedented data set for understanding the movements, habits and lives of blue whale populations. Along with, tragically, their deaths.
They noted that populations of other baleen whales were rebounding after restrictions on whaling went into effect, and they expected the same of blue whales, but their projections weren’t matching the reality. When they dug deeper, the culprit became clear. Blue whales tend to flock towards areas of marine upwelling like San Francisco and Santa Barbara because these sites are rich in food supplies, and blue whales, as you might imagine, need a lot of food. Sadly, such sites are also located along major shipping lanes, and host considerable fisheries (humans are also interested in marine upwelling and all the edible species found in these areas). This puts whales and ships on a literal collision course.
Many ships on these lanes are so large that they may not even notice if they hit a whale, especially if it’s only a glancing blow. Smaller vessels may notice, but are not always eager to report ship strikes — and even when they do, the damage has already been done. Researchers eager for solutions to this problem have looked at how other regions of the world have implemented a humane balance for whales and human trade, and they’ve found that shifting shipping lanes slightly can often significantly ameliorate the risk of ship strikes. Furthermore, slowing the speed of ships around busy ports and areas of known whale activity can also provide significant protection to whale populations. Slowing down ships can provide them with an opportunity to spot and avoid whales (an important consideration for cargo ships, which can take 5 miles or more to stop, even with engines in full reverse).
Putting these solutions in place would require cooperation across several agencies, including national and international agencies concerned with shipping regulations and boating safety, as well as law enforcement agencies charged with ensuring that ships of all shapes and sizes comply with the regulations. In addition, it’s clear that researchers need to continue tracking whales to learn more about their habits, as much about the lives of whales is still deeply mysterious, much like whales themselves. The greater our understanding of whales, the more we can do to protect them — and the more likely it is that they will survive for future generations to admire.
Photo credit: Dan Shapiro for NOAA.