TRACKING THE MIGRATION Scientists use visual observation and photography to track individual gray whales during their annual migratory journey
During the Festival of Whales, keep your eye—and camera—out for the Eastern North Pacific (California) gray whale making its long journey down the coast of California. You’ll be witnessing the longest annual migration (10,000-12,000 miles) of any mammal on Earth, in much the same way scientists observe and track the By Kayla Causey whale population. The gray whale is a baleen whale that lives to be 50-70 years old and can reach a length of about 50 feet. Every October, after filling up on tiny crustaceans buried in the sea floor, 20,000 gray whales leave the Bering and Chukchi Seas of Alaska to find mates and birth calves in the warm—and orca-free—lagoons of Baja, Mexico. Gray whales fast during their entire journey—an incredibly taxing feat for a female whale who will soon birth and nurse a 13-foot, 2,000-pound calf. In California, we’re privileged to often see migrating gray whales right from our shores, thanks to their use of the coastline for navigation and protection from predators. Once they reach the lagoons between late December and early February, gray whales spend the next few months birthing and nursing calves and concluding their breeding season. In February and March, the first whales begin the northbound migration back to Alaska. Usually these are pregnant females. Mothers—referred to as cows—with
The “knuckles” on the back of a whale are one of the physical features researchers use to identify and study individual animals. Photo courtesy of James Gresham
newborn calves are the last to leave, and do so only when their calves are ready for the long journey home, usually in late March to mid-April. A gray whale nurses her calf for the entire journey up the coast, eating very little herself until she returns to the feeding grounds off of Alaska. Her milk is over 50 percent milk fat—think half-n-half coffee creamer—and her calf consumes between 50 and 80 gallons a day—about the amount contained in a large barrel. This continues for six to seven months. As a result, she loses over 30 percent of her body weight on the northbound migration. Once again in the cold waters of the Arctic, whales resume feeding. They do so by plowing up the ocean floor and filtering the mud and sand for crustaceans. Their “filter” is about 150 baleen plates, which are overlapping layers of hair-like bristles made of keratin—much like human fingernails—on the inside of their mouths. One whale alone will plow about 1-acre of sea floor between May and October. Nearly hunted to extinction in the 1850s and early 1900s, gray whales were protected under the Endangered Species Act in 1969. They have since been removed after recovering to numbers in excess of 21,000. However, scientists continue to monitor the abundance of this population for two related reasons: They are important
“ecosystem engineers” because they redistribute large amounts of material when plowing up the seafloor, making food available for other marine species, and their annual migration makes them very vulnerable to environmental conditions. For instance, if Arctic sea ice breaks up very late in the spring, the feeding season is shortened and females can not store the fat necessary to maintain a pregnancy. As a result, birthing rates decline and low birth weight calves often don’t survive the northbound migration. We saw this pattern in 1999-2001 (data provided by Wayne Perryman of the National Marine Fisheries Service). Because gray whales are such an important part of their ecosystem, even a short-term variation in feeding patterns can have longterm impacts on the population and its environment. How do scientists track individual whales for study? One method we use to study these whales is to track individuals during their migration using photo-identification techniques. Rather than “tagging” a few animals with trackers, scientists photograph as many gray whales as they can. Then we use the photos to take measurements of these whales’ “knuckles,” the ridges on their back where you might expect a dorsal fin to be. We can use the relative distance between these ridges to assign a “dorsal ratio” as an identification number for animals we photograph. Data can then be used to determine re-sighting rates for whales migrating through Dana Point. This helps us understand whether the same whale follows the same route during each leg of the migration and/or year after year. We can also estimate the cumulative number of gray whales that migrate off of Dana Point. This information is important in helping scientists determine the role that our local waters play in the gray whale’s great migration. Kayla Causey received her Ph.D. from Florida Atlantic University in 2010. Currently, she is the scientific advisor for the Gulf of Catalina Gray Whale Preservation and Education Foundation, a nonprofit organization that educates children about the Gray Whale while engaging them in research. Causey is also director and founder of the Coastal Dolphins of Orange County (CDOC) Project and a lecturer at CSU Fullerton. On the weekends, you will find her working as a naturalist on whale watching adventures. DP
PARK AT THE PARK, WALK WITH THE WHALES Doheny State Beach offers ample $8 all-day parking, whale sightings guaranteed When it comes to great adventures, sometimes getting there is a big part of the fun. And this year’s Festival of Whales is no exception. Doheny State Beach has not only taken some of the stress out of parking but also added a fun way to begin your festival adventure—the Doheny State Beach Interpretive Association Whale Walk, where whale sightings are guaranteed. DSBIA volunteers began to return life-sized paintings of whales to the walkways along Doheny Beach in January. They started with three—a California gray whale, an orca and a humpback—and will be adding more species of whales and dolphins in the coming months. The Whale Walk was a longstanding tradition at the park, absent for the past six years since being paved over during walkway maintenance. Now children once again will be delighted by seeing how they “measure up” to the behemoth marine mammals and 10
giving their parents a nice photo op upon arrival to the festival. The Doheny parking lot—enter at Dana Point Harbor Drive and Park Lantern—is offering all-day parking for only $8. Most Harbor lots are four-hour maximum and are monitored by the Orange County Sheriff’s Department. Not only is this a whale of a deal, it’s also a great way to avoid the stress of having to continually watch the clock while discovering everything the festival has to offer. And free shuttle pick-ups to and from events and attractions are scheduled at 15-minute intervals. So start your visit off right—park at the park, walk with the whales, ride the free shuttle and enjoy a worry-free day at the festival. For more information about the Whale Walk and the DSBIA—including how to become a volunteer—visit www. dohenystatebeach.org. DP —Andrea Swayne
Volunteer K.C. Kinnings puts the finishing touches on the new Whale Walk’s orca. Photo courtesy of Doheny State Beach Interpretive Association
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