April 12, 2010
California Gray Whale Numbers Dwindling
After being removed from the endangered species list in 1994, the California gray whale has drawn thousands of fans to watch the peaceful goliaths make their way down the coast to their spawning grounds in Baja.
But recently, whale-watching boat captains have become alarmed after sightings of the whales have dropped from 25 a day in good years to only five a day this year. Conservationists and officials are now worried about the future of the species based on the figures.
"If you count 2,500 animals, all you really know rock solid for sure is there are more than 2,500. Beyond that you're using models and assumptions," said Stanford University marine biology professor Steve Palumbi to the Associated Press (AP). "The problem comes when you say, "ËWe do know how many whales there are and we're going to start making unalterable management decisions on that basis.'"
The study is based on population estimates made annually since 1967. However, only three census counts have been done in the past ten years, the most recent in 2006. Since then, the estimated number of calves has dropped from more than 1,000 in 2006 to only 312 in 2009. In addition, the species suffered a great loss, after several thousand whales died in 2000.
The California Coastal Commission urged the National Oceanic and Atmospheric Administration in January to perform a gray whale update study. The count has been taken, but the analysis will not be complete until long after the whaling commission makes its decision.
NOAA says the population estimates are reliable because the numbers have remained consistent over time. They say the drop in calf numbers may reflect nature thinning out the herd. One of the study's co-authors, Paul Wade, said the population is still more than double what it was in the 1960s and has been fairly stable the past two decades.
"If it truly does go into an important decline, it's not going to happen overnight. We're going to see it," Wade told AP.
NOAA researchers have not been as concerned with the gray whale populations as they are with other species that are very endangered, including the Northern Right Whale, which only 30 are known to be in existence. However, scientists have conducted a great amount of research on gray whales over the years, and offer that there should not be any great alarm or concern for their immediate well being.
NOAA biologist David Rugh told AP, "Of course we have a concern about them going through so many environments from Mexico to the Arctic but there are other species out there that we're also concerned about."
Gray whales migrate thousands of miles each fall from Alaska to Baja, then return north between February and May. They spend their summers in the Bering Sea and the Arctic. As the whales swim south, biologists at a small stand along the central California coast count them. The whales are counted again as they make the northward trek in the spring. The counts are used to estimate the overall population and monitor reproduction.
In 1970, when the whales were on the endangered list, there was an estimated 12,000 whales. A ban on commercial hunting and close monitoring led to a population rebound to more than 20,000.
Once removed from the endangered list, the whales needed to be monitored only once every five years instead of annually, and funding for the whale census ceased, which cost about $170,000 per season.
A count in 2006 yielded only 2,500 individuals, and led researchers to calculate about 20,000 whales total. A calf count in 2009, though, revealed the fewest since 2001.
Wayne Perryman, who oversees NOAA gray whale counts, told AP that he believes there is a link between lower reproduction rates and colder winters when lingering ice blocks whales from getting to their feeding grounds. He feels that there should be no reason for panic.
The International Whaling Commission allows the Russian Chukotka people and the Makah Indian tribe in Washington to hunt 140 gray whales per year. The commission reopens the issue every five years, but is also considering limits through 2020.
On the Net:
- International Whaling Commission
- California Coastal Commission
- National Oceanic and Atmospheric Administration