North Atlantic right whales have made headlines lately, and not just because they’re spending time off the coast of Cape Cod. Sadly, reports about the endangered whales have focused on the news that birth rates are now below the mortality rate – indicating population decline. Just three calves were born this winter, the lowest rate in at least 15 years.
A birth rate lower than the mortality rate means that not enough calves are being born to replace the ones that are dying. A likely factor in the decrease of births is the whales’ difficulty in finding reliable food sources. Without adequate fat storage, female right whales are giving birth every seven or so years instead of the normal rate of every three years.
This is troubling for any wildlife species, but especially so for the North Atlantic right whale, of which scientists say just 524 or so remain. (100 are breeding females.)
The recent designation of the Northeast Canyons and Seamounts Marine National Monument – the first of its kind along the Atlantic seaboard – may help provide these whales with more reliable food sources. Science shows the monument area to be rich with marine wildlife, and with the 4,913 square miles protected from most industrial activity, undisturbed populations of plankton and copepods could help these whales in the long run.
Restoring food sources, though, is a long game, that faces a tougher trajectory as the ocean is becoming more and more crowded and temperatures are rising. With right whales moving around more often in search of food, they are at increased risk of facing their two largest (human-caused) threats: becoming entangled in fishing gear and being hit by a ship.
Right whales tend to swim close to the surface, making them potential targets for ships that are moving quickly and/or don’t see the whales. The good news is that mortality rates from ship strikes are no longer increasing (even as ship traffic increases) after regulations were put into place requiring ships to decrease their speed in certain areas frequented by right whales during certain times of year. The bad news is that ship strikes are still a leading cause of death for right whales – averaging about one per year.
Fishing gear entanglements
Approximately four to five right whales die each year due to fishing gear entanglements, making it the leading cause of death for the species. In September 2016, Whale 3694 died of “chronic entanglement.” This death was even more heartbreaking than usual since she was of breeding age. It remains unclear whose fishing gear – or even which type of fishery – was responsible for the whale’s death.
Thankfully, there are groups working to understand which types of gear are most responsible for the deaths, and how changes in material and/or flexibility could help pose less of a risk for right whales. The Marine Mammal Commission is focusing its 2017 annual meeting on right whales; New England Aquarium’s Anderson Cabot Center for Ocean Life has a research program aimed at finding solutions; other groups like the North Atlantic Right Whale Consortium and the Center for Coastal Studies – among many others – are working together to get right whales back on track toward population growth.
It’s worth noting that scientists are also working to identify other factors that could be at play to explain this year’s dramatically low number of calves, such as population-wide illness, pollution issues, or a genetic dysfunction. Calving season typically goes through the end of this month, so it’s possible we may still see another calf born before the winter is over.
The recent news is disappointing, and with attacks on the Endangered Species Act potentially brewing in congress, it’s critical that this work continues.
Read more about the North Atlantic right whale in our species profile, and share this post on Twitter with the #WorldWildlifeDay hashtag to help us raise awareness.