HUMPBACK WHALES
HAWAII'S HUMPBACKS HEAD NORTH FOR THE SPRING AND SUMMER!
As many as 10,000 humpback whales may visit Hawaiian waters every year from
November through May. During the spring and summer the North Pacific humpback
whales migrate north to cooler waters where they feast on krill and small
schooling fish. Scientist speculate that the whales use ocean currents,
temperature changes, acoustical cues, and even the earth’s magnetic field to
find their way to Hawaii (the most remote island chain in the world).
Humpbacks are mammals belonging to the order Cetacea, which includes whales,
dolphins and porpoises. The common name “Humpback” is derived from the
distinctive arch of the whales’ backs when diving. Humpbacks weigh about 40 tons
and can be up to 50 feet length; females are slightly larger than males. Their
average life span is between 30 and 40 years.
Humpback whales generally swim in pods, the basic social group consisting of the
cow (female), a single calf, and “escort” male. Most Humpback behaviors seen in
the Hawaiian Islands are related to courtship and mating, which places the cow
at the center of socialization during the winter months.
Humpbacks communicate via a wide variety of sounds produced by circulating air
through the tubes and chambers of their respiratory system. Their “concerts” are
best heard on whale watching trips equipped with a hydrophone (underwater
microphone). Humpbacks are generally curious about objects in their environment
and will often approach and interact with boats. It is not uncommon for whales
to come up alongside the boat or even swim beneath it. Captains nicknamed these
events “whale muggings” because legally they cannot move the boat until the
whale has departed. From this close you can hear the blow (an exhalation at 300
m.p.h.) and the loud slaps of tails, flukes and breaches. Hawaii’s “100 yard
minimum rule” states that people (whether on boat, kayak, swimming or by any
other means) may not approach within 100 yard of a Humpback whale.
Humpbacks have developed an ingenious method of cooperative fishing called
bubble-net feeding. First, hunting members of a pod form a large circle deep
below fish and krill. The whale then blows a cylindrical wall of bubbles as they
swim upwards in a spiral path. The bubbles confuse the fish and krill,
concentrating them at the surface and making an easy feast for the whales.
There are currently 30,000 – 40,000 Humpback whales worldwide. Federal laws
protect Humpbacks, however their habitat is under great pressure from
over-fishing and pollution. You can help protect Humpbacks by preventing marine
debris and pollution and supporting eco-friendly companies and organizations.
