Their voyage of up to 12,000 miles (20,000 kilometers) from the Arctic Circle to the Baja California Peninsula and back is the longest known mammal migration, one of the most studied by scientists, and most watched by tourists. The gray whale (Eschrichtius robustus) of the eastern North Pacific Ocean was nearly hunted to extinction until it was protected in the 1940s. Today — thanks to science-based restrictions on hunting and carefully regulated watching — the mammoth marine mammal has nearly recovered to its pre-whaling population.
The gray whale is 46-feet-long (14 meters) and weighs an average of 35 tons (32,000 kg). They are the only cetacean that are bottom-feeders, rolling on their side and sucking up sediment from the seedbed, then filtering out everything but amphipods and other small crustaceans that are retained by their baleen plates. They generally feed only when in Arctic waters, and during peak feeding periods, adults may consume a ton of food per day. They swim south between October and February, then head north again between February and July.
Research conducted since 1996 by the Autonomous University of Southern Baja California (UABCS for its name in Spanish) has yielded valuable information about the gray whale’s behavior in its breeding area, findings that are being used to control whale-watching tourism and fishing. Gray whales are so easily studied and watched because they are large and slow, and during their migrations from their feeding grounds in the Bering, Chukchi, and Beaufort seas to the western coast of the Baja California Peninsula where they reproduce, they seldom swim farther than six miles (10 km) from the shoreline. In a behavior called “spyhopping,” they sometimes rise vertically out of the water, then sink slowly back beneath the waves. Scientists think spyhopping may help them navigate, by allowing the whales to orient themselves to the shoreline, or it may be social behavior.
Whale watching has become big business in Baja California, where the whales court, mate, and reproduce in the San Ignacio and Ojo de Liebre lagoons of the El Vizcaíno Biosphere Reserve, and in other lagoons in the area. “Gray whale-watching is a tourism industry that, when well managed, can be economically interesting,” notes Jorge Urbán, director of the Marine Mammal Research Program at UABCS. Local residents have a positive attitude because it is making money for them.”
The UABCS gray whale research project is funded by the US Fish and Wildlife Service, Packard Foundation, and Mexico’s National Biodiversity Commission, Secretariat of the Environment and Natural Resources, and the Exportadora de Sal Company.
University studies have shown that the birth interval of the gray whale is 2.5 years and the whales remain with their young in the lagoons up to two months. Gestation lasts a year to 13 months, so the pregnant whales swim north to the Arctic, then calve when they return to San Ignacio’s lagoons a year later. Female whales usually give birth to just one calf. Biologists now know how many whales visit the lagoons, what the carrying capacity of each lagoon is, and how long each whale stays in the lagoon according to their age and sex.
Whale-watching regulations based on UABCS research prohibit the entry of launches into the lagoons. Research in the El Vizcaíno Biosphere Reserve also helped define a whale-watching zone, the distance tourist boats must stay from from the whales, and how they should be approached.
According to Lorenzo Rojas, Coordinator of the National Marine Mammal Program of the National Ecology Institute in Mexico, local residents strictly follow the regulations established for whale sightings, because they are aware their livelihoods depend on the whales’ well being. They also respect a ban on fishing from January to March, when the whales are present, so there are few cases of the mammals getting tangled and trapped in fishing nets.
“The fishermen of the zone understand well that income from whale-watching can be equal to or better than what they were making before the tourists came, and they have adopted the gray whale as a symbol of their culture and their community,” Rojas says.
He adds that they also recognize that their support for protecting the lagoons, declared as a World Heritage Site thanks to the effort of the biologists, is also key to the species’s survival. Urbán points out that another gray whale population in Asia is on the brink of extinction with fewer than 100 individuals. This population of gray whales migrates between feeding grounds off Sakhalan Island in Russia and calve in some unknown location, probably in the South China Sea. Gray whales also once migrated along the North Atlantic coast, but whalers completely wiped them out in by the 18th century.
In contrast, the whale habitat protection along the western American continent, coordination of protection efforts among Mexico, the United States, and Canada, and the vigilance of the people of Southern Baja California, has helped the gray whale population recover to about 25,000 individuals.
— Katiana Murillo
Contacts in Mexico:
Instituto Nacional de Ecología
Read more about this project in the Eco-Index: