Virtual Viewing
Inside Passage Audio Guide
Humpback Whales
Transcript
Humpback whales
Humpback whales are the most commonly sighted and abundant whales in Southeast Alaska.
Marine biologists have been studying humpback whales in Southeast Alaska for decades. Some individual animals, identified by the pattern of white and black on the tail and distinctive marks and scars, have been monitored for almost 30 years. Researchers estimate there are about 1,000 humpback whales in Southeast Alaska in the summer. Studies show that whales return to the same areas year after year to feed, and individuals seem to favor specific locations.
Southeast Alaska's humpback whales migrate, spending summers in food-rich northern waters and wintering in the warm waters off Hawaii, where they mate and give birth. Gestation takes about 11 months, so a female that mates one winter will return to the tropics the next year to have her calf. The 3,500-mile migration takes about a month each way. The whales feed heavily in Alaska, eating almost 1,000 pounds of food a day. This food energy is stored as blubber. In the winter the whales generally fast, living off their fat reserves.
Bubblenet feeding is a cooperative feeding behavior seen in Southeast Alaska, but uncommon elsewhere. A school of fish, such as herring, is corralled into a tight ball. One whale dives beneath the school, circling and blowing bubbles. The bubbles rise through the water column as a kind of disorienting curtain surrounding and confining the school of fish. As this ring of bubbles reaches the surface, the group of whales lunges up through the prey, gulping tons of water and feed.
What to Listen for: The "whoosh" of the exhaled breath (the spout or blow) of a humpback can often be heard across the water. Although humpbacks are famous for their singing, this behavior is mainly associated with mating. It is rare in Alaska in summer, although some males will sing intermittently in the fall. They do vocalize in other ways. The most common is a loud, low, trumpet-like blast, which may be used to herd schooling fish or coordinate feeding activities with other whales. These sounds, uttered underwater, may be heard on the surface. A vessel at rest with the engines off can lower an underwater microphone (known as a hydrophone) and play the sounds through stereo speakers. The smack of a whale's tail and flippers on the surface and the splash of a breeching whale can also carry across the water.
What to Look for: The distinct white puff of the whales' spout is usually the first sign of humpback whales and can be seen more than a mile away. The spray from the whales' exhalation may linger for 10 or 15 seconds, standing out against the water as a misty plume about 10 feet high. The whale's blowhole is located on the top of its head, and the low, dark shape of the head and the knobby blowhole can be seen as the whale spouts.
In Southeast Alaska, feeding humpback whales usually surface, spout and breathe four or five times over a one to two minute period, then make a longer dive. The amount of time a feeding humpback spends submerged varies, depending on how deep it is feeding and the type of feeding activity. About five minutes is common. However, it's not unusual to wait 15 minutes for a whale to surface, and they can stay down for as long as 30 minutes.
Whales rarely show their tail flukes when cruising just under the surface, and they usually do show their tail flukes when making longer, deeper dives. When a whale first surfaces, note the direction of travel and try to anticipate where it will come up next. You will likely have several good opportunities to see the animal before it makes a longer dive.
During the "breathing session" at the surface, the whale first shows its blowhole and part of its back as it takes a few breaths. When it finally makes the deep dive you see the length of the whale - the rounded, rolling curve of the back, the small triangular dorsal fin, the tail stock or peduncle, and finally the massive flukes of the tail.
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Marine Mammal Code of Conduct
1. Remain at least 100 yards from marine mammals.
2. Time spent observing individual(s) should be limited to 30 minutes.
3. Whales should not be encircled or trapped between boats, or boats and shore.
4. If approached by a whale, put the engine in neutral and allow the whale to pass.
5. Federal law prohibits pursuit of marine mammals.
For more information on marine mammal viewing visit http://www.fakr.noaa.gov/protectedresources/mmv/guide.htm