Safe Passage: NOAA Scientists and Gray Whales are Forging New Paths

April 22, 2012
 

It was a story ripe for Hollywood...at the height of the Cold War, on the frigid edge of Alaska, a motley crew came together to open a path to survival for three young gray whales. The true story that inspired the hit film Big Miracle was a tale of unlikely cooperation. Today, the story continues as NOAA scientists and their partners in the U.S. and abroad work to unravel new mysteries of the gray whale odyssey.

A Beloved Icon

These days, the California gray whale is a beloved icon, drawing crowds to the beaches for a close-up look at these migrating denizens. Their journey is one of the longest made by any mammal, covering over 12,000 miles round-trip, from rich feeding waters in the Alaskan Arctic to the placid lagoons of Baja California Sur, where they gather each winter to mate and give birth. In early spring, the northward journey begins anew, mothers and their calves hugging the coast for protection. The calves are only a few months old and still clumsy. The shallow coastal water provides shelter from killer whales, who have baby gray whales at the top of their menu. Gray whale mothers are known to protect their vulnerable calves fiercely. 

Big Migrations Require Energy

Each spring, a dedicated group of NOAA scientists gathers to witness this spectacular voyage and detect changes in the population. On a windswept rock on California’s central coast, the team settles in for weeks of diligent observation. This April, the NOAA Fisheries team is at Piedras Blancas conducting the 19th census of gray whales in the Eastern North Pacific. Census project leader Wayne Perryman, from NOAA's Southwest Fisheries Science Center, says calf birth rates appear tied to Arctic ice cover in the whales’ feeding grounds. The further north the ice edge retreats, the further the whales must swim to return south. The whales already burn plenty of energy during the long annual migration, so having to travel even further leaves less energy for breeding or for the survival of unborn whales. The last few years bear this theory out. In 2010 there were 254 calves, and in 2011 there were 850 calves. The population in the Eastern North Pacific is stable at around 20,000 whales, but there have been large fluctuations in the birth rate since the census began in 1994. This year, Perryman expects “a big year for calves,” and he says that the adults seem to be healthy and “in good nutritive condition.”
 

Left image: As sunset approaches on Laguna San Ignacio, gray whales cruise through the placid lagoon. Right image: A gray whale spyhops to get a better look at the scientists in Laguna San Ignacio.  Credit: Dave Weller, NOAA SWFSC.

Where Exactly do Gray Whales Go?

We’ve learned much about gray whales in the last few decades, but there are still mysteries unfolding. This spring, a team of NOAA researchers partnered with whale experts in Mexico to apply new tagging technology to track the whales (read more about how whales are tracked). The biggest question: where exactly do the whales go? There are a number of reasons this matters more than ever. Their journey takes the whales through the busiest shipping lanes on the U.S. West Coast—those serving the huge port of Long Beach, California. As recent entanglements off Southern California have shown, the whales also swim through areas where fixed fishing gear is used. Entanglement is a challenge worth tackling – it’s hard on the whales, and hard on fishermen whose gear gets damaged. Massive cargo ship strikes are often fatal to whales. Better tracking can help us to understand and manage our marine areas better. Sometimes, in pursuit of that knowledge, we cross borders, brave the unknown, and carve out a new path.

Gray whales have the longest migration of any mammal, more than 12,000 miles roundtrip from Alaska to Mexico. Credit LT Claire Surrey-Marsden  

Transnational Collaborations

Dave Weller, a biologist with NOAA Fisheries in La Jolla, California, has been working with Russian biologists since 1995 to study a critically endangered population of gray whales off Sakhalin Island in far eastern Russia. This group of about 130 whales is genetically distinct from the Eastern Pacific gray whales. Genetic studies indicate that the two populations seldom interbreed and it was long thought that they didn’t mingle. A 13-year-old male named “Flex” changed that assumption. Tagged off Sakhalin Island in 2010 by a team of scientists from Russia and the U.S.*, Flex traveled all the way to Oregon before his tag went silent. The next year, a female named “Varvara” was tagged by the same research team working off Sakhalin. What she did next was astonishing. She crossed the deep and dangerous Bering Sea and continued down the North American coastline to the breeding lagoons in Baja California Sur. She lingered there for a few weeks, visited all three lagoons, then retraced her route north toward Alaska. Her tag is still transmitting. You can follow her journey.

The Mystery Remains

Flex and Varvara's travels help to paint a more detailed picture of gray whale migration. The last two Arctic winters have been warm. So warm, in fact, the ice sheet that formed a barrier between Pacific and Atlantic surface waters retreated, opening the Northwest Passage for the first time in generations. What do all these changes mean for gray whales? Weller and his colleagues now see the potential to find a big piece of the puzzle. Flex and Varvara let us tag along with them, but the winter travels of their companions are shrouded in mystery. Weller is hopeful that he and his long-time NOAA colleague Bob Brownell can gain permission to enter China, and alongside their Chinese colleagues, talk with fishermen and “place a pin on the map” where gray whales have been seen in recent times. “There are very few records of where to look for gray whales along the Asian coast, but we know they are there from recent strandings and sightings. Whaling records from the 1800s give us a place to start, but we need to talk with people who live along that coastline, and find out where the whales spend their time now,” Weller says.   

 *Note: This research was conducted by A.N. Severtsov Institute of Ecology and Evolution of the Russian Academy of Sciences (IEE RAS) and Oregon State University Marine Mammal Institute in collaboration with the U.S. National Marine Fisheries Service, Kronotsky State Nature Biosphere Reserve and the Kamchatka Branch of the Pacific Institute of Geography. The research was contracted through the International Whaling Commission (IWC) and International Union for Conservation of Nature (IUCN) with funding from Exxon Neftegas Ltd. and Sakhalin Energy Investment Company Ltd.