The birth of 11 North Atlantic right whale calves this breeding season so far is an encouraging sign for one of the most endangered whale species in the world. However, this time of year is one of the whales' most vulnerable as ship strikes account for many calf deaths.
“With only about 340 North Atlantic right whales remaining, the survival of every newborn is essential to prevent the extinction of this species,” said Jane Davenport, senior attorney of Defenders of Wildlife and right whale conservation expert. “We know right whales can recover if we act to stop human-caused deaths and stresses on reproduction.”
North Atlantic right whales give birth between mid-November and mid-April in the warm coastal waters of the southeastern U.S. from North Carolina to Florida. The region is the only known calving habitat for this species. Since the breeding season is far from over, there is hope that births this season may exceed last year’s number of 15 calves. However, it's hard to know exactly how many will be born. In 2018, no right whale calves were born, leading to fears for the species’ future.
Tragically, one of this season’s calves was found dead in Morehead City, North Carolina. As the whale was a newborn and emaciated, it may have died after being separated from its mother. Unfortunately, such natural mortalities among calves are not uncommon, which is why preventing human-caused deaths is essential.
The birth of new North Atlantic right whales each year is always a cause for celebration. However, scientists say that because of high human-caused right whale mortality, at least 50 calves would need to be born each year to avoid extinction. It’s not biologically possible, as there are currently less than 70 female right whales left that can breed. At best, they generally only give birth to one calf every three years. However, a shift in foraging habitat (primarily due to climate change) and the stress of chronic entanglements in fishing gear mean that many females take far longer to calve again, up to 10 years.
“We do not have the number of new births needed to avoid extinction, so we need to dramatically reduce the number of whales killed by human activities and reduce stressors on reproduction instead,” said Davenport.
One of the two major threats to right whales is vessel strikes (the other is entanglement in commercial fishing gear). The whales’ migration routes and feeding grounds between Florida and Atlantic Canada mean they must cross some of the busiest shipping routes on the East Coast. Moreover, it’s not just giant cargo ships and tankers that kill right whales; smaller vessels can and do kill whales when traveling at speed.
Mothers and calves are particularly at risk of vessel strikes because they swim close to the surface and stay close together for months. In 2020 and 2021 alone, three right whale calves were killed by small vessel strikes, one-off New Jersey and two off Florida. One of these incidents involved a 54’ fishing charter vessel returning to port at night. The boat killed a calf and its first-time mother, meaning all her future calves were lost to the species. The boat itself was totaled, and it was only due to luck and the captain and crew’s quick action that there were no human injuries.
Right whales are some of the world’s largest animals. At birth, calves are 13-15 feet long and weigh around 2000 pounds, while adults are 45-55 feet long and can weigh up to 70 tons. Right whales are notoriously difficult to spot from boats, even in ideal weather with calm seas during full daylight. Their upper (dorsal) sides are mostly black, they lack a dorsal fin, and they spend most of their time swimming below the surface. Reducing vessel speeds to 10 knots or below dramatically reduces whale injury and mortality.
“The good news is that we already know what we need to do to minimize the risk of whale-vessel collisions and protect vulnerable mother-calf pairs from vessel strikes,” said Davenport. “Similar to slow zones around schools to protect children going to and from school from cars, we’ve had a rule in place to slow down large vessels (65 feet and larger) to 10 nautical miles per hour (“knots”) or less in certain areas during the months when right whales are most likely to be there.”
Defenders and its conservation allies have worked for decades through advocacy and litigation to build on the successes of the 2008 rule and expand its protections to larger areas and smaller vessels. In 2012 and 2020, we petitioned the federal government to expand the 2008 vessel speed rule based on the best available science showing that seasonal speed zones work.
“The federal government finally proposed expanding the rule in August 2022,” said Davenport. “We are particularly concerned that the proposed rule is too late to finalize it before the start of the current calving season.”
In November 2022, Defenders and its allies filed an emergency petition calling for an emergency rule to implement the proposed rule’s expansions in the Southeast to protect vulnerable mother-calf pairs at this critical stage of their lives.