Each year, the start of the calving season for critically endangered North Atlantic right whales kicks off on November 15th.
From there, our office anxiously waits every day as reports come from the latest aerial survey flown over the calving area. These surveys fly over the southeast US to count the number of North Atlantic right whales and see if there are any new moms and calves.
Just like much of 2020, the first sighting of a North Atlantic right whale calf was different than we have ever experienced before. Sadly, the first calf sighted was a stranded newborn male right whale on the shores of North Carolina. A necropsy (animal autopsy) was conducted by researchers in hopes of understanding why this little one did not make it, but a difficult labor and delivery is in the back of everyone's mind.
The tragic news does come with a sliver of hope. While it may seem like we are grasping for straws, it is still good news that there was a female who sustained a pregnancy and made it to the calving grounds. Even though this little one didn’t make it, a successful pregnancy is a step in the right direction.
The potential loss of the calf due to dystocia (complication during labor and delivery) is sad, but unfortunately is not entirely unexpected. We do not know how often it happens in wild populations of whales as calves lost during labor do not always strand and can easily go undetected. However, cases of dystocia have been documented in dolphins and manatees due to complications such as the calf being poorly positioned during labor. Human babies are born head first as that first gasp of refreshing air is essential. However, cetacean (whales, dolphins, and porpoises) babies are born tail first. That first gasp of refreshing air needs to wait until the baby is fully out and can swim to the surface.
The calving interval (how many years apart a mom gives birth) has increased in right whales from 3-4 years to nearly 10 years between pregnancies! This increase may, in part, be due to females being less “fit”.
Healthy right whale moms needs to be fat enough to produce hormones that will allow them to get pregnant and to also have enough blubber to feed themselves and their developing babies. To get thick blubber, right whales need to eat lots of food. Unfortunately, our changing climate has shifted some of their food further north in Atlantic Canada. The colder water there allows for the plankton (favorite food of right whales) to survive.
So instead of swimming about 1,300 miles from their calving habitat (red oval) to their historic feeding area off the coast of New England (blue oval), some right whales are adding another 800 miles+ to their trip by heading into the Gulf of St. Lawrence (green oval). A longer swim for food is more calories burned and less weight gained. This makes it more difficult for these whales to be fat enough to have a successful pregnancy.