While today we are confident of seeing thousands of gray whales off our shores during the migration period and several hundred year round, there once was a time when this regularity was gravely threatened. Because of their habitual nearshore migration patterns, grays were predictable targets for shore-based whalers. Shore stations were set up along the California coast in the 1800’s. Whales were thick during the winter breeding season in San Diego Bay where a station was established in 1855. Just 18 years later, the population had been so depleted that the station closed due to a lack of whales. All of the California shore stations closed by 1895. However, whaling continued in the Mexican breeding and calving lagoons, where the whales were easy targets. The practice of harpooning calves to draw the mother close to the whale boat resulted in many whaling boats being attacked by enraged mothers, which earned them the nickname “devilfish.”
By the turn of the century, there may have been only 2-4,000 gray whales remaining. In the early 1900’s, the Mexican government finally protected the Baja breeding and calving grounds that had been decimated by whalers. International protection for the gray whale came in 1937 from the League of Nations when it was widely recognized that the species was endangered. The ban on killing gray whales was reinforced in 1946 when the International Whaling Commission was created. Despite a complete cessation of commercial whaling, it was decades before there were any signs of significant population growth. The Pacific stock was in such danger that it was placed on the Endangered Species list in 1970, which prevented international trade in animal parts and required a consultation on development within the species’ range (e.g. offshore oil and gas). Grays received additional protection in the United States under the Marine Mammal Protection Act of 1972, which forbade harassment that might alter the animals’ behaviors or use of preferred habitats. Eventually, after 57 years of protection, the Pacific gray whale stock had recovered and the species was removed from the Endangered Species list in 1994. The population is presently estimated at 26,600, a number thought to be close to the pre whaling population.
Gray whales once lived in the Atlantic also, but were wiped out by whaling. Both Pacific stocks (Eastern and Western) were almost lost as well because of human greed, but efforts to reverse this grim trend and foster the gray whales’ recovery are heartening. This does not mean that gray whales are free from harm. While whaling no longer threatens the eastern Pacific stock of gray whales, the western Pacific stock numbers only a few hundred individuals and a whole host of other threats exists for both populations - pollution, oil spills, development in their habitats, ecosystem changes and harassment from ever increasing human activity in the marine nearshore area.
Although our understanding of gray whales is better than for any other species, it is unfortunately still limited. Most of what was garnered from whaling records will not help us with contemporary issues. Marine mammal research has always been handicapped by the huge size of the ocean, by the expense of mounting expeditions across this vast surface, and by the fact that whale behavior is difficult to observe as they spend less than 5 percent of their time on the surface. Knowing the critical habitats of whales - where they breed, calve, feed, and migrate - is vital to the conservation of endangered whale species. For most species of large whales we only know their whereabouts for four to six months of the year. Where they are for the rest of the year is what we are trying to discover.
Technological Developments
The obstacles involved with studying these great whales can be overcome, especially by utilizing today’s advanced technologies. More that twenty years ago, the Oregon State University Marine Mammal Program (MMP) started using short-range VHF radio tags to partially circumvent these obstacles. Subsequently, the OSU program teamed with small technology firms to develop satellite-monitored radio tags and continues to advance this new technology. Satellite tags have several advantages over the other tools - photo identification and conventional radio tracking (VHF/HF) - that have typically been used in whale research. The latter techniques require both great commitments of researchers’ time and vessels. Photo identification enables researchers to recognize individual animals when they are resighted, but leaves their movements between sightings (days, months, or years) a mystery. Conventional radio tracking requires that researchers maintain close vessel contact with one single animal at a time. In contrast, satellite tracking allows the OSU team to follow numerous whales at the same time from our research lab at the Hatfield Marine Science Center in Newport. It takes the same initial expenditure of time to tag whales with satellite-monitored tags as it would to attach conventional radio-tags, but numerous animals can be track simultaneously, in all weather conditions, without the need for expensive ships and researchers’ time to maintain radio contact and recover data.
Once the whales have been tagged, the team returns home to monitor the whales’ daily movements from computers for less than the cost of lunch. Satellite tracking now allows us to follow the movements of each whale, both above and below the surface. When a tagged animal returns to the surface after a dive, the radio tag sends its data to satellites which then transfer the information to MMP computers. Satellite technology reveals the route of migration, rate of travel, and destination of individual whales anywhere in the world. The MMP is continually making improvements as we strive to make a longer-lasting tag that can provide us with even greater amounts of information.
Satellite technology has remarkably changed our knowledge of the whale species we track. The MMP regularly dispels earlier thinking about some species and discovers previously unknown critical habitats for others. For example, we have discovered the migration routes of Hawaiian humpbacks to known feeding areas along Alaska and British Columbia, as well as new areas along the Aleutian Islands and the Kamchatka Peninsula of Russia. We have also tracked the southern fall migration of blue whales feeding off California to the first probable breeding/calving area, 300 miles offshore Costa Rica. Only by understanding where these animals travel can we effectively protect these important habitats. The gray whale is a prime example of how habitat protection has allowed the population to rebound.
Gray Whale Migration and Critical Habitats
Although the migration of gray whales may seem like a simple movement between summer and winter “homes,” significant disturbance in any of its critical habitats can affect the population. The whales’ principal feeding habitat is along the shallow Bering Sea shelf where an adult may ingest up to two and a quarter tons of benthic (bottom-dwelling) amphipods (small crustaceans) daily. Gray whales are the only whale species which primarily feast on organisms that inhabit the ocean floor. They spend May through November building their energy reserve for the migration to the breeding and calving grounds because most do not eat again until they return north. Females need even more energy than males to develop a one ton calf every other year and then suckle it for six months. In early winter, even before ice encroaches upon the Bering Sea, the whales begin to migrate south. The stimulus to migrate may be a particular day length. Pregnant females are the first whales to arrive in the calving areas of Mexico. The south-bound and north-bound migrations take six to eight weeks each. Variable periods are spent in the calving grounds depending on the whale’s age, sex and reproductive state. Although pregnant females were first to leave the Bering Sea, they are also the last to migrate north because the new mothers have to wait until their 15 foot long “baby” gets strong and accumulates enough blubber to make the journey north into colder waters. In total, grays spend at least three months away from the feeding grounds, and calving females may be away as long as five months. Thus, the quantity and quality of food the grays consume in the Bering Sea is key to a successful migration.
Scientists studying the Bering Sea over the past two decades have noticed a dramatic decline in the productivity of the region. The Bering Sea has typically been a highly productive ecosystem, supporting more than 450 species of fish, crustaceans, and mollusks, 50 species of seabirds, and 25 species of marine mammals. As such, it has been the source of 40 percent of the U.S. fisheries catch and 10 percent of the world catch. The productivity decline, which is on the order of 30 percent, has been reflected in the fish catch for several years. Unlike an El Nino event, which takes place over one to two years, this decline is called a “regime shift” or a “decadal oscillation” meaning the event is spread out over a much longer period of time. Other marine mammal populations, such as Stellar sea lions, harbor seals, and sea otters - as well as bird populations - have also notably declined in this region, but the causes have not been determined.
This year’s gray whale migration has proven interesting for the community of researchers who study these mammals both in the United States and Mexico. Events surrounding this year’s migration may be linked to the changes in the Bering Sea ecosystem. Between 1978 and 1981, OSU conducted yearly surveys of migrating gray whales in Oregon. This past winter, the MMP again counted gay whales from Yaquina Head lighthouse as they migrated south past our coast from December through March. We were surprised by the absence of significant numbers of grays off Oregon until late December, three weeks later than “normal.” Despite the delayed start, the peak of this year’s migration passed only a day later than the latest peak we observed during our earlier studies.
Other observations proved this past migration season unusual as well. Over the last two decades, volunteer observers for the American Cetacean Society (ACS) have been counting gray whales during the south-bound migration along the Los Angeles coastline. Some calves are born en route north of Los Angeles. In recent years, ACS has seen increasing numbers of calves. These births are an indicator of each year’s calf production. Last year, 106 were seen; this year, only 15 were spotted, suggesting perhaps lower calf production. During an annual MMP natural history trip to San Ignacia Lagoon, Baja California, Mexico, our group observed fewer females with calves than normal. Mexican colleagues studying whales in Baja’s breeding lagoons also noticed lower calf production than normal.
Since 1975, Mexican researchers have noted only three other years with “high” numbers (45-52) of whale deaths. In past years, however, most of the dead animals were calves-of-the-year. This year, the majority of the animals were adults (mostly female) and many of the rest were yearlings. During the north-bound migration this past spring, observers also reported numerous gray whales dying along the Pacific coast. The most recent counts show that 167 grays were found dead along the Mexican coast and 112 animals have been found along the shores of California, Oregon and Washington. The numbers are continuing to climb. These differences from other years make this year’s winter season quite unusual. The deaths have been spread out over a wide geographic range and a period of months, making a toxic event (e.g. a spill or cyanide-based dyes used by drug runners) a highly unlikely cause of death. The number of deaths observed do not correlate merely with population growth. They are inordinately high.
The decline in Bering Sea productivity may have put gray whales under nutritional stress due to lower quality (calorie) and/or less available food resources. Poor nutrition may have made the animals more susceptible to diseases. This nutritional hypothesis could explain why the whales started their migration late; they may have remained in the feeding area longer than usual to build up their blubber layer before beginning the migration south. It might also explain low calf production and high adult female mortality (the age and sex group with the most demanding energy requirements). Unfortunately, diagnostic information from the dead whales that might be used to confirm this idea is difficult to obtain, especially if the bodies washing ashore are not “fresh”. Blubber samples have been taken from dead whales and will be tested to determine fat content. Most whales are at a seasonal low point for fat during the northbound migration because they have been going without food for so long. This is especially true for mothers who suckle their calves with milk which is 50 percent fat. Whalers tended to ignore these “dry skins” on the northbound migration because the whales yielded very little oil. This year, gray whales in southern California were observed surface skim feeding on krill right next to humpback and blue whales, suggesting that the grays were too hungry to pass up a feeding opportunity even if it wasn’t their usual fare. Locals have never reported this type of activity by gray whales.
What we are seeing is likely a normal process. However, we do not fully understand the impacts of natural environmental change. This is a rare and exciting opportunity to see how whale populations at or near the “carrying capacity” of their environment respond to such changes. Carrying capacity - the theoretical limit of how many animals can be supported in each trophic level - is not a fixed number, but rather fluctuates as the environment changes (dynamic equilibrium). The last time such a large scale “recovery” occurred for gray whales was after the last ice age, 11,000 years ago, when the shallow Bering Sea again became accessible for feeding. We know the critical habitats of gray whales, what they eat and how the population has recovered from exploitation, and we can monitor their nearshore mortalities. We don’t know these parameters for any other whale species. Thus, the opportunity to understand what is happening to gray whales in response to their environment is absolutely unique. Knowledge of gray whale habitats and habits was critical to the species’ recovery. In recognition of the importance of the Baja lagoons as breeding and calving grounds, Mexico prohibited whaling in these areas, fostering the gray whales’ recovery. Conversely, our lack of knowledge impedes adequate protection and recovery of whales that are still endangered. The MMP strives to discover the habits and habitats of gray whales and other endangered whales to improve their chances of future survival.
San Ignacio Research
San Ignacio Lagoon is the smallest of three well-known breeding and calving lagoons along Mexico’s Baja Peninsula. The other two are Laguna Ojo de Liebre (Scammon’s Lagoon) and Magdalena Bay. San Ignacio Lagoon was declared a whale refuge by Mexican presidential decree in 1976, designated part of the Vizcaino Biosphere Reserve (the largest in Latin America) in 1988, and named a Natural World Heritage Site by the International Union for the Conservation of Nature in 1993. The northern two-thirds of the lagoon is closed to tourism and fishing activities during the breeding and calving season. The southern third, nearest the ocean, permits closely regulated tourism where limited numbers of people can experience the majesty of these whales and the importance of this habitat with skilled guides. The impact of such activities on the whales is negligible, and the experiences build advocacy groups which support and protect whales and their critical habitats.
Support for habitat protection is important as development pressures start to impinge upon this area vital to gray whales. A proposal to build a salt production facility on the shores of San Ignacio Lagoon is currently being developed. Finding suitable employment for residents of this desert region is difficult. Traditionally, fishing and ranching have been the major sources of income. The author is on the scientific committee that will review the environmental impact assessment for all activities associated with the proposed process. While the evaporation of seawater may seem like a natural and environmentally safe process, there are still concerns to be considered. The committee will have to weigh the possible impacts associated with: (1) increased boat traffic which may harass whales, (2) possible contamination of the lagoon by toxic brine by-products, and (3) the entrapment of larval fish into the evaporation ponds which may threaten the local fisheries. When the MMP began studies of the gray whales visiting San Ignacio Lagoon in 1979, our purpose was to develop tagging technology and to prove that their migration route could be tracked using conventional short-range radio tags. We were successful in this endeavor, tracking one adult from the lagoon to Unimak Pass, the entrance to the Bering Sea, in 95 days. Since this first tracking success, we developed satellite-monitored tags while studying other species. In 1996, the MMP returned to study further the gray whales of San Ignacio Lagoon, but our goals had shifted. They were twofold: how many whales actually use this lagoon habitat and how important is this habitat to the population? To help answer these questions, our most recent research focused on two issues: (1) the length of time individual whales spend in the lagoon, along with their movements in and around the lagoon, and (2) the migratory route of the whales as they leave the lagoon. Understanding the length of stay and movement helps us estimate the number of whales that use the lagoon. Knowing the grays’ migratory route helps us better understand their exposure to localized risks (e.g. an oil spill) they may encounter en route, which could impact the entire population.
MMP researchers tagged 12 gray whales in San Ignacio Lagoon during the 1996 field season. Six of these were females with calves, who stayed within the protected breeding and calving lagoon much longer that whales without calves, suggesting the importance of the area for newborns. The MMP tracked the path of one adult whale on its north-bound migration from San Ignacio to northern California at a speed of 80 miles per day. Its route went along the western most Channel Islands off southern California. There has been recent concern that noise and vessel traffic may be causing gray whales to take a more offshore route during their migration. Researchers are unsure if noise is an issue or if the whales are just saving energy by taking the most direct route. Cause and effect relationships are difficult to prove on such a large scale, especially without controlled experiments.
Endangered Whales
As human activity increases in the marine environment, concerns will continue to arise. Because the gray whale has recovered, it is not considered a world conservation priority. There are other animals, however whose fate is more uncertain, species which have become depleted as a result of whaling.
The history of whaling is one of overexploiting one species after another. The larger species, blue, right and sperm whales, were taken first. When their populations were decimated, whalers targeted fin, humpback and gray whales. Only the smallest and most abundant of the filter-feeding whales, the minke, is still hunted commercially, though regulated by quotas. In this century, people killed over two million whales in the worlds’ oceans. The regions depleted of whales are unlikely to be repopulated by more abundant whale stocks from other oceans because stocks in different oceans do not appear to mix. For example, even though the California gray whale population has rebounded, it will not move into the Western Pacific, where the stock is depleted. While none of the endangered whales are still commercially hunted, human activities continue to impact many of them. Several species, driven to the brink of extinction by the whaling industry, have not recovered despite up to 60 years of “protection”
One of these species, the North Atlantic right whale provides an interesting contrast to the huge strides the gray whale population has made. Northern right whales are considered the most endangered of all whales, with only 300 remaining in the North Atlantic. Sometimes the whales’ biological processes serve as an impediment to recovery. Right whales have lower reproductive rates than gray whales, producing a calf every four to five years on average versus gray whales which calve every other year. Unfortunately, humans also remain an obstacle for right whales as our activities inadvertently kill them or compromise their use of important areas. One of every two right whale deaths is due to a vessel collision, doubling their natural mortality rate. Fifty-eight percent are scarred from fishing gear entanglement or vessels. It is important to know where these problems occur!
Not hunting is not enough protection for these endangered animals. We must find out where whales live and protect those places if they are to survive. Similar protection was extremely important to gray whales’ comeback and will be even more so to right whales. If the present pattern of human impact does not change, right whales will go extinct within the next 100-200 years.
The MMP is uniquely positioned to uncover many mysteries of the great whales. As these mysteries are uncovered, humans can act to change their activities to accommodate the habits and habitats of the great whales. Humanity is privileged to be the custodians of the earth and its inhabitants. When we observe the spouts of the gray whales passing our coast, we must realize that the progress we have made with gray whales can be repeated for other endangered whales. The research of the MMP is the catalyst; all of us are the stewards of this research, its results, and its implications. We can replicate the recovery of the gray whales if we invest in research, are committed to ecological change, and learn from our historical mistakes.
