For 15 years, Kenny Manzoni of Adventure Rib Rides has been motoring paying customers out of San Diego to watch whales and other marine mammals. He recalls the late 1990s, when he sometimes saw in a single season as many as several hundred gray whale calves, newly born in Baja California and migrating north along the coast with their mothers, bound for their summer sub-Arctic feeding grounds in the Bering Sea.

But this season, between late winter and early spring, Manzoni laid eyes on just six calves.

“It’s been a downward trend for at least the past three years,” Manzoni said. “We’re seeing fewer whales and less calves, with this year probably the fewest ever, and the whales we are seeing appear to be underfed.”

Similarly, observers in Baja have reported fewer pregnant females and births in the shallow waters of San Ignacio and Ojo de Liebre (formerly known as Scammon) lagoons, popular destinations for wintertime whale watchers. According to whale activist Sue Arnold, thousands of breeding and birthing gray whales may crowd into Ojo de Liebre in a normal year. In 2009, however, observers saw only 578. Arnold, who is the chief executive of the California Gray Whale Coalition, visited the lagoons this winter and says it was no better than the last, making 2010 the fourth consecutive year of diminished breeding activity.

Most winters, Arnold says, “You can hear them all across the lagoon, singing and talking, but this year it was silent. It was spooky.”

Observations by biologists with the National Oceanic and Atmospheric Administration confirm that gray whale calf counts are down dramatically from a decade ago. In 2009, observers stationed at the Piedras Blancas lighthouse near San Simeon counted just 86 calves migrating northward, the lowest number ever recorded. In better years, the count has come in at five times as many — like in the spring of 1998, when observers saw 440 northbound calves. Biologist Wayne Perryman with the oceanic administration’s Southwest Fisheries Science Center in La Jolla says 2010’s numbers are still being processed, but he suspects the final calf count could be as low as 2009’s.

Manzoni, Arnold, and many others, including biologists, believe they know just what is plaguing the world’s last viable population of gray whales: the animals are going hungry in their summer feeding grounds, and the culprit seems to be global warming and sea ice melting. Most summers, gray whales grow fat in the Bering Sea, just south of the Arctic Circle and west of Alaska, by feasting on small shrimplike, mud-dwelling amphipods, which in turn subsist upon algae that form on the underside of the sea ice above and precipitate as the sheets melt each summer. However, such algae fail to grow when the sea does not freeze, and the effects of this phenomenon are rippling up the food chain, all the way to gray whales, say biologists. Without sufficient amphipods, which whales sieve from the seafloor mud with their baleen, the whales are failing to gain the strength they need to migrate south and mate. Some whales that did make the trip this year, according to Manzoni, were so emaciated that their rib cages could be seen through their skin.

While scientists grapple with data and struggle to understand the animals’ reduced breeding activity, gray whales are facing another peril as the International Whaling Commission prepares to accept or reject a proposal that, among other things, would allow indigenous hunters of northeastern Russia to kill up to 140 gray whales every year from 2011 until 2020. The commission, a group of 88 member nations, begins reviewing the proposal on June 21 in Morocco at its annual meeting. Hunters of the Russian Federation already kill up to 140 whales per year on a five-year contract program, but the new proposal would grant hunters the go-ahead for the next ten years. It would also require that commission biologists evaluate the ecological impacts of whaling just once every two years — a reduction from the current mandatory annual evaluation. United States Inuit hunters in Alaska would receive a similar ten-year quota on killing bowhead whales, and yet another component of the proposal would legalize the whaling “for scientific purposes” currently conducted by Japan, Norway, and Iceland in return for each nation promising to take slightly fewer whales every year. This, say critics, would effectively end the 24-year global moratorium on whaling.

If the commission rejects the proposal, gray whale hunting by the Russian Federation will continue on the current five-year contract system with annual reviews.

Arnold, like other conservationists, firmly opposes the proposed ten-year extension on the hunt and believes a full moratorium is in order.

“The draft proposal says that if the whale population experiences a significant event, the hunt could be called off,” she said. “But it doesn’t define ‘significant event.’ We’re saying that a significant event is already happening.”

Researchers across the country agree that sea-ice disappearance is affecting the behavior and life cycle of gray whales. Jacqueline Grebmeier, a biologist with the University of Maryland’s Chesapeake Biological Laboratory, has studied the food web of the Alaskan Arctic water column for decades. Grebmeier says ice-free water has allowed the whales to move north of the Bering Sea, but how successful they will be in finding food there is unclear. Off the northern coast of Alaska, in the Beaufort Sea, most of the waters are too deep for the whales to reach the bottom, says Grebmeier, though she says that they are finding amphipods in the muddy seafloor off Point Barrow and even utilizing other food sources in midwater.

Dave Rugh, wildlife biologist with the Alaska Fisheries Science Center in Seattle, believes gray whales will cope successfully if sea ice continues to vanish. The animals are currently using new feeding grounds in the Beaufort, he says. Some whales have even traveled much farther. In early May, for instance, a gray whale was seen swimming off the coast of Israel. The sighting has stirred debate and controversy worldwide among cetacean experts. Some have speculated that the whale could represent a miniscule remnant population of the Atlantic gray whale, though this animal is recognized almost universally as extinct, wiped out 200 years ago during the height of the whaling era. Only an estimated 135 western Pacific gray whales survive, migrating along the coasts of Russia and China.

Thus, most experts agree that the Israel gray whale was born in a Baja lagoon. Members of the California Gray Whale Coalition have cited the event — perhaps the first case of an eastern Pacific gray migrating over the pole — as evidence of desperation, while Rugh sees it as a case of new feeding and migration opportunities.

“The disappearance of sea ice has allowed whales to explore farther north,” said Rugh. “One even got to Israel.” He says climate change is incorrectly characterized as a universally harmful phenomenon; whales, he predicts, “might find it advantageous for a while. Sure, it’ll be bad for polar bears and walruses, but it could be good for gray whales.”

But mass starvation caused by reduced ice formation has occurred among gray whales. In 1999 and 2000, the warming effects of El Niño prevented ice from forming over much of the Bering Sea. Experts believe that as many as one-third of the gray whales starved, many of the corpses washing ashore on California beaches, though the total population of gray whales before the crash is unknown. Information provided by the National Oceanic and Atmospheric Administration shows a starting population of about 21,000 whales in 1998, dipping to just over 16,000 in 2002, and subsequently climbing again to roughly 19,000. Another agency report, produced in part by Dave Rugh, says the population in early 1998 might have been as high as 32,427. However severe the crash, gray whales have experienced only two seasons of high breeding success in the years since, according to Arnold, and she doubts the population has recovered.

Biologists once believed the mass starvation of 2000 came as a result of the whales reaching the maximum carrying capacity of their environment. In 2007, however, Stanford researchers studying the wide range of genetic variation within the existing gray whale population concluded that as many as 118,000 might once have swum in the eastern Pacific. This pre-whaling figure would suggest that new environmental conditions — namely sea-ice disappearance and breakdown of the marine food web in the Bering Sea — are now limiting the food supply of gray whales.

The National Oceanic and Atmospheric Administration’s last official estimate of the gray whale population came in 2006, a figure of 19,600 animals based on data collected that same year in Baja and in California. The International Whaling Commission is factoring this figure into its current management regime. Sarah Graham, the Moss Landing–based West Coast manager of the California Gray Whale Coalition, believes a fresh population estimate is overdue. Perryman said such a figure will not be available until sometime in 2011.

“The whale-population numbers aren’t being properly presented,” said Graham, who suspects the gray whale population in the eastern Pacific could number as few as 16,000 animals. “They’re using 2006’s numbers as evidence that it’s okay to keep hunting [gray whales].”

Gray whales rebounded from near extinction a century ago and were removed from the federal endangered species list in 1994, but in response to Stanford’s pre-whaling population estimate of 118,000, conservation groups are now advocating an effort to relist the whale as threatened. Stanford whale researcher Stephen R. Palumbi wrote a letter in March 2008 to the California State Assembly urging the state to take action. He warned that the changing environment would likely lead to whale starvation, perhaps on par with the event of 1999–2000.

Palumbi also warned that should gray whales migrate farther north seeking food in a warming environment, they could encounter oil- and gas-drilling activity in the Chukchi Sea, off Alaska’s oil-rich North Slope, and the Barents Sea, north of Finland.

Norman Sanders, a retired UC Santa Barbara professor of environmental studies, believes the federal government is more interested in preserving oil-drilling possibilities than whales.

“It seems to me that [the National Marine Fisheries Service, a division of National Oceanic and Atmospheric Administration] wants to take no action that will interfere with offshore oil drilling,” said Sanders, who serves as a scientific advisor to the California Gray Whale Coalition. “That would be too much political mess for them, and so they aren’t being honest scientists. They’re afraid their funding will dry up if they get in the way.”

Perryman, of the fisheries center in La Jolla, has acknowledged the decline in breeding activity in Baja California but believes short-term weather changes rather than long-term climate patterns could be the cause. He also cautions against underestimating the whale population.

“I think that the conservation effort has to be based on getting facts straight, not on being alarmist,” he said.

Numbers are hazy in the field of gray whale research, yet Arnold believes ample cause for alarm has arrived.

“What is the benchmark for acknowledging that this population is in trouble?” she said. “We’ve had four years of low calf counts in Mexico, and whale-watch captains are reporting emaciated whales.” Why, she asks, is such information not sounding alarms? “Are we going to wait for six years of low calf counts? Or ten years, or until there are no calves at all? When do we call this an emergency?”