Baby Boom Comes After
Several Years of
Declining Birth Rates
NMFS Northeast Region
N E W SWoods Hole, Mass. -- Teams of biologists surveying ocean waters off Florida and Georgia have sighted at least 14 right whale calves in the last two months. (Editor's note added May 7: A total of 30 calves were sighted by the end of the calving season) This is more new right whales than the scientists observed in the previous three years combined. The right whale baby boom is extremely good news for a species whose chances for survival have been looking increasingly grim.
"Fourteen births is very good news," said Phil Clapham, a whale expert with NOAA Fisheries, the federal agency charged with developing a plan to protect the endangered whales. "There are only about 70 reproductively active females left, and they have been having calves less frequently than in the past, for reasons that are not clear," he said.
Officials cautioned that the population increase is only one small step toward recovery of the highly endangered species. There are approximately 300 North Atlantic right whales left, and recovery efforts have been hampered by whale injuries and deaths caused by collision with ships and entanglement in fishing gear.
"These births are the best possible news," said Pat Kurkul, regional administrator for NOAA Fisheries in the Northeast U.S. "Recognizing that there may be some natural mortality among the calves, it is important that we keep working to reduce the threat of entanglement and ship strikes in order to give these new whales every opportunity to grow up and contribute further to the population."
Scientists from a network of public and private agencies monitor the remaining North Atlantic right whales closely throughout the year. In the winter months, pregnant females migrate to the southern waters to give birth. Survey teams composed of scientists from the New England Aquarium (NEA), Georgia's Department of Natural Resources (DNR), and Florida's Fish and Wildlife Conservation Commission (FWC) scour southern waters looking for right whale mother-and-calf pairs.
The teams found only five live calves in 1998. In 1999, only four calves were sighted, and last year there was only one confirmed sighting of a calf.
This year the southern survey crews began flying December 1, with Early Warning System (EWS) flights contracted by NOAA Fisheries, funded by the U.S. Navy, the Army Corps of Engineers, and the U.S. Coast Guard, and conducted by scientists from New England Aquarium. The EWS flights focus on a 1,000 square mile patch of shallow water off southern Georgia and northern Florida, and serve the dual purpose of locating and photographing right whales for scientific purposes and alerting ships in the area to the presence of right whales that might be in their path.
With funding provided by NOAA Fisheries, a team from Georgia's DNR flies farther north, up the coast to Savannah. Florida's FWC covers the Florida coast farther south, and the two states jointly operate a survey in offshore waters out to 40 nautical miles.
The survey teams fly at low altitudes (approximately 1,000 feet) until they spot right whales, when they bank and descend to take photographs that researchers at the NEA back in Boston use to identify individual whales. Battling fog and strong winds in December, the EWS team was nonetheless able to mount 18 flights during the first month of the season, recording 31 right whale sightings that included five or six different calves.
"Despite less than optimal weather, we saw a pile of whales in the first month," said Chris Slay, a biologist from the New England Aquarium who heads up the Early Warning System in the southeast. "Last year we had just six right whale sightings in 80 flights, and we saw just one calf all year. Needless to say, morale is better this year."
By January 23, Slay's team had logged 32 flights with 66 right whale sightings that appear to include 13 different calves. A 14th calf was sighted by the Georgia DNR team.
"And we still have another dozen or so females in the area who could bring forth more young this year," Slay said.
The Florida FWC survey team that covers the southern most portion of the calving ground, has logged 22 right whale sightings in the past three weeks, compared with a single sighting at the same time last year.
"The teamwork and coordination between survey teams has resulted in extensive coverage of the calving ground, giving us an overall picture of the population," said Cyndi Thomas, head of the FWC right whale conservation project. "We are also providing protection from ship strikes by immediately distributing our sightings to mariners in the area."
Barb Zoodsma, Senior Biologist for the Wildlife Resources Division of the Georgia Department of Natural Resources, said the sightings a reason for cautious optimism. "Although this is great news, we must remember how close to extinction this species really is and continue our combined research efforts," Zoodsma said.
The boom in right whale births may provide new evidence to scientists who have been trying to solve the puzzle of why right whale birth rates have been declining. Last spring, NOAA Fisheries brought together a panel of whale experts and other scientists – including experts in reproductive biology of other endangered species – in an attempt to understand the declining birth rates. The possible explanations included diminishing food supplies, disease, the presence of biotoxins or other contaminants in the marine environment, or a genetic problem caused by inbreeding in a too-small population of animals.
"Most of the possible explanations are pretty discouraging," Clapham said. "If the problem is inbreeding, it is quite likely that you are stuck with it."
Likewise, disease or biotoxins are the types of difficult-to-solve problems that might well spell doom for the species. But the reproductive successes this year may indicate that the past problems were something periodic, such as a diminished food supply or perhaps an epidemic that may have left the females unable to reproduce.
"The food supply explanation is the only hypothesis for which there is any real evidence," Clapham said, citing a recent blubber thickness study by Michael Moore and Carolyn Miller, scientists at the Woods Hole Oceanographic Institution. Moore and Miller found that female right whales have diminished blubber thickness – raising the possibility that they were not healthy enough to have calves as often as they had in the past. In a different study, researchers at the Center for Coastal Studies in Massachusetts have suggested a link between food supplies and later reproductive success.
Not only is the nutrition hypothesis the only explanation supported by evidence, it is also the most hopeful scenario.
"These are long-lived animals," Clapham said. "If the problem is a variation in food, the females should be able to survive year to year fluctuations and produce enough calves in good years to slowly rebuild the population – if we can reduce the deaths from entanglement and ship collisions."