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Spring Brings Humpback Whales to Feed in Monterey Bay
By Nancy Black
Humpback
whales have arrived in large numbers to feed in Monterey Bay. As of May 1st, our
counts indicate there are at least 40 to 50 humpbacks in the Bay feeding on large
schools of anchovies. This is a key indicator that we are entering a new season
off the California coast -- the prime feeding season for whales, dolphins, and
seabirds. The gray whale migration is nearing an end, but we expect mother/calf
pairs of gray whales to continue past our coast through May on their way to Alaska.
The humpback whales that are currently in Monterey Bay have just arrived
from their breeding areas off the coast of southern Mexico and Central
America. Humpback whales are an endangered species with a population of around 1,000
that migrates from Mexico to California each year. Humpbacks occur in all the
oceans and there are at least three separate populations in the North Pacific.
Once they arrive at California they begin feeding off our coast through the
summer and fall.
Their arrival at Monterey Bay coincides with the upwelling season. During
this period, afternoon winds drive the nutrients from the deep up to the
surface, and the sun fuels massive plankton blooms. This provides food for
fish and krill, which are consumed by humpback whales, blue whales, dolphins,
other fish, and seabirds.
Humpback
whales are among the most interesting and spectacular whales to watch, as they
often breach, lunge feed (where nearly half their body lunges out of the water
with the mouths open and throat pleats expanded to engulf tons of water with their
food), pec slap, tail slap and exhibit other surface behaviors. Sometimes they
even become curious about our boat and will hang out right next to us as they
spyhop, roll on their sides, blow bubbles and exhibit what we call "friendly whale"
behavior.
When the humpback whales arrive, Monterey Bay Whale Watch switches to 5-6
hour trips. Since the whales are feeding and not migrating (as the gray
whales do), they move around the Bay and outer waters searching for the best
feeding areas. We need enough time to reach all their feeding areas, plus
plenty of time to watch them. With this trip length, we can often find
both humpback and blue whales plus several kinds of dolphins and occasionally
killer whales, minke whales, fin whales and beaked whales.
Currently, the humpback whales are feeding on massive schools of anchovies. Each
day the whales have been moving with the fish schools and we have been locating
them inside and near the edge of the Monterey Submarine Canyon. We have also been
sighting large groups (1,000 +) of Risso's dolphins and Pacific white-sided dolphins.
The dolphins are farther out over the edge of the canyon, feeding on squid and
anchovies. With the changing seasons, many seabirds are also arriving, including
black footed albatross and thousands of shearwaters.
In addition to running our regular whale watch trips, we are working with the
National Geographic Society for the third year on a film about Monterey Bay and
our research on killer whales. As part of this research project, some of our biologists
are out every day on our second boat searching for killer whales. At this time,
the killer whales frequent Monterey Bay in search of mother/calf gray whales.
They are hunting the gray whale calves, and we are studying these incredible predation
events. Unlike the humpback whales, killer whales are unpredictable and we never
know when we will find them.
So as we continue into the spring, we expect more humpbacks to arrive
each day along with the possibility of killer whale predation events and
large numbers of dolphins. Monterey Bay has historically been a prime feeding
area for humpback whales, and at one time in the early 1900's they were
heavily hunted here. In the last few years, the numbers of humpbacks feeding
in the Bay has been increasing and we hope they are reinhabiting the
productive waters of Monterey Bay. Our biologists continue to photo-identify
all individual whales and contribute the photos to the large project underway by
Cascadia Research Collective to monitor the population and recovery of the
North Pacific Humpback whales.
See our Photo Gallery for whale and dolphin photographs taken during April and May 2000.