There is some good news about the population of North Atlantic right whales: after seven years of declining numbers from 2013 to 2020, there has been a small increase in their population — enough to suggest a “leveling off” of that steep decline.
This is certainly welcome news, but it requires some perspective. Right whales are among the world’s most endangered large whale species, and their population remains significantly smaller than it was a decade ago. There were only 358 of these critically endangered whales counted in 2020 — an all-time low, according to the most recent survey estimate from the North Atlantic Right Whale Consortium, which releases new data at its annual meeting every October.
The numbers are complicated. They include not only an estimate for 2024 but also updated population numbers for previous years. The lookback is done because the count is actually a multiyear undertaking that involves a built-in delay in officially cataloging calves and adding them to the population estimates.
Here’s how that works: Calves that have been born and observed are added to the catalog only after the calf is photographed later, traveling with its mother, nursing, and deemed healthy. Researchers try to re-identify the calf, matching it with photographs taken in later years. Sometimes, this just doesn’t happen. Other times it may take a few years to accurately link a new sighting to the record of a particular calf’s birth.
The 2023 population model departs from that system and accounts for new calves sooner instead of waiting for them to be cataloged. So, the newly released population estimate for 2023 now stands at 372, a number that includes 12 calves from 2023.
The estimates are the result of a cooperative endeavor between research scientists at the New England Aquarium’s Anderson Cabot Center for Ocean Life and the National Oceanic and Atmospheric Administration, which has been calculating and tracking trends in the right whale population since 1990.
In the most recent calving season — from December 2023 to March 2024 — 20 calves were born. That is the most calves born in one season in 10 years. Unfortunately, this rather encouraging news is offset by the fact that five calves did not survive past the spring. And 20 is still slightly below the average of 24 calves born every year during the early 2000s.
While right whale births have increased compared to recent years, so have right whale deaths caused by human activities. And the 2024 mortalities were particularly alarming because a few of them included females with calves. There were five documented birthing female mortalities and four lost calves that have not been found and are presumed to be dead. That was the highest annual mortality count since 2019 and the third highest on record.
The presence of the mothers is essential to the calves’ survival, and the mothers are of course fundamental to maintaining the current population rebound.
Ship strikes and fishing gear entanglement are the two most common reasons for right whale deaths. The 10-mile-per-hour coastal and bay speed limit imposed in the spring during their northern migration and the ban on lobster gear seem to have addressed the issue — but only partly.
While we are doing what we can close to shore, large ship strikes that happen farther offshore are surely responsible as well for right whale deaths. And that issue seems to be overlooked as far as navigational regulations go.
Considering that as many as 50 right whales were observed feeding in an unexpected place this year — the Hudson Canyon, in and around the offshore shipping lanes — protective enforcement should probably be done to minimize the danger of strikes there. We will wait to hear if anything is forthcoming on that issue this winter.
