Gray Whales Are Heading To Monterey Bay
As the days become colder and fall changes to winter, here in Monterey Bay we notice the seasonal change by the animals that arrive for winter and those that depart. Monarch butterflies arrive to their sanctuary in Pacific Grove to overwinter; a variety of birds such as loons, grebes, and ducks leave their northern breeding grounds to spend the winter in Monterey Bay. Millions of shearwaters, seabirds that never go to land except to mate and raise their young, spend summer and fall feeding in our rich waters then migrate down to New Zealand and Chile to reproduce. Arctic terns have all passed by Monterey Bay from the Arctic Ocean on their way to Antarctica for their continual summer. Humpback and Blue Whales head to their wintering areas off Mexico and Central America after gorging on the abundance of krill and fish during their summer and fall feeding season off Monterey.
the most anticipated animal that arrives predictably to Monterey Bay every
year in early winter is the Gray Whale. At 45' long and 45 tons, Gray
Whales are magnificent mammals that represent a tremendous success story.
At one time nearly hunted to extinction with just a few hundred whales
left, they now number over 23,000 and were taken off the endangered species
list in 1994. This year we are celebrating 10 full years since the Gray
Whale was removed from the endangered list. No other whale has yet reached
such pre-whaling numbers, but hopefully given more time the other endangered
whales will match the success of Gray Whales.
the Grays' northbound migration past Monterey Bay, Killer Whales are searching
for the Gray Whale calves that are born during January in Mexico and travel
with their mothers past Monterey Bay during spring on their way to Alaska.
The mothers and calves are the last whales to leave their protected lagoons
and pass Monterey nearly a month after the peak of the adult Gray Whales.
The mothers and calves closely hug the coast as they travel north. When
the whales reach Monterey Bay they generally cross the Bay and the deep
submarine canyon where their migration path crosses the deep-water habitat
of the Killer Whales. The Killer Whales patrol the canyon edges in search
of the Gray Whale calves. When a Gray Whale calf is located, one of the
greatest predation events on earth occurs -- several 5-ton Killer Whales
battling a 45-ton Gray Whale mother and her 10-ton calf for up to six
hours. If successful the Killer Whales gain a rich and abundant source
of food for over 20 whales.
this is a yearly event, last spring (2004) our research team led by marine
biologist Nancy Black documented an unprecedented event, as far as the
frequency of Killer Whale sightings and the number of attacks and feeding
events on Gray Whales. After several years of relatively low numbers of
Gray Whale calves and a significant decrease in the Gray Whale population,
the number of calves born in 2004 was the highest since counts by the
National Marine Fisheries Service began 10 years ago. Wayne Perryman,
who heads these counts, believes that more calves survive through full
term and are successfully nursed during years when whales have an abundant
and predictable food source in the Bering Sea, which occurred during the
summer of 2003. Last spring, many calves passed through the Bay each day,
with a peak of around 40 mother/calf pairs per day compared to less than
10 in previous years.