Right whales came by their name because they are slow moving, have lots of blubber, and tend to float when killed, making them the "right" whales to kill in the eyes of hunters. Researchers estimate that as many as 80,000 to 100,000 northern right whales once roamed the North Atlantic Ocean. Now, the numbers are fewer than 300. Even though they have been protected from hunting since 1935, the northern right whale's numbers do not appear to be increasing.
For the past three years, Biology Prof. Solange Brault has been studying data on northern right whales to assess their health and prospects for survival. Along with colleagues from the Woods Hole Oceanographic Institute, the New England Aquarium, and several graduate students, Brault has been analyzing extensive photographic records of individual northern right whales which date back to 1980. The records identify them by their calluses and scars. Some of the whales have names - - Stumpy, Quasimodo, and Radiator - - the latter so named because of a distinctive pattern of scars on his back made by a boat propeller.
Brault gathers information about when and where the whales have been sighted, and if and when an identified female is accompanied by a calf, using the photo records and a method known as "mark recapture analysis."
This method, which is used to track populations of small mammals and birds, usually requires animals to be captured, tagged, released, and then monitored at intervals to estimate population size and survival rates. In the case of the northern right whales, the photographic records serve as "tags," allowing them to be monitored by researchers who follow their seasonal movements.
"Our goal is to find out what is the survival rate, and what is the fertility rate, so that we can know if the population is increasing or decreasing," says Brault. "Right whales are long-lived - - 30 years for males, 50 years for females. We know that in the 1980s females appeared to have calves on the average of once every three years: One year for feeding and care of a new calf, one year for rest, and one year for gestation," explains Brault.
In the 1990s that pattern appears to have changed. "We don't know why. It could be due to either aborted fetuses, or early death of the calves," says Brault. "But there is an indication of lower fertility."
There have been other indications that the whales' normal patterns of behavior are disturbed. Every summer, researchers go to the Bay of Fundy to observe a group of northern right whales at their summer feeding grounds. This year, the whales left early. The reason is unclear, but Brault thinks that it may have to do with changes in the patterns of ocean currents in the North Atlantic. This in turn affects where the whales find their main source of food, tiny, shrimp-like creatures called copepods.
In addition, the whales still face many other dangers. For one thing, the coastal areas these whales inhabit are also major shipping lanes. "The right whales sleep on the surface of the water, and we know they get hit by ships," says Brault.
They also get entangled in fishing nets and gear. Brault says that things can be done to improve whales' chances for survival. Fishing gear modification, such as "pingers" attached to nets to warn the whales away, and early warning systems for ships, which alert the crews to whales in their path, are two examples.
Brault's research interests are life cycle processes and how they influence survival and reproduction within animal populations. She and her colleagues have received approximately $50,000 in funding from the Massachusetts Environmental Trust and The Northern Marine Fisheries Service for the northern right whale studies.