Humpback Whales in Papahanaumokuakea
Humpback Whales (Megaptera novaeangliae) were once on the brink of extinction, but their numbers have dramatically increased to approximately 10,000 migrating to Hawaii each winter. Along with this steady increase in the number of whales, is a geographic expansion from the main Hawaiian Islands into the Papahanaumokuakea Marine National Monument.
Researchers deployed nine electronic listening posts known as Ecological Acoustic Recorders (EARs) in both Papahanaumokuakea and main Hawaiian Islands to record the occurrence of humpback whale song. Song is produced by male humpback whales during the winter breeding season. Humpback Whale song was found to be prevalent not only in the Main Hawaiian Islands, but right up the archipelago into the Northwestern Hawaiian Islands from late December to mid-May.
It is not yet clear how many whales use the northern islands, but this area has twice as much shallow warm water habitat as the main islands. More whales were detected in the middle waters of the region, and fewer in the colder waters of the northernmost atolls. Song was found to be prevalent at Maro Reef, Lisianski Island, and French Frigate Shoals, but was also recorded at Kure Atoll, Midway Atoll, and Pearl and Hermes Atoll.
Humpback Whale Song Patterns
Humpback Whales learn new songs as adults, and gradually and progressively and collectively change the sounds and patterns within their songs throughout their lives. The song is made up of several different themes, and each of these themes is sung in the same order. They repeat a phrase of notes several times in one theme before moving on to another. For example, if the themes are A, B, C, D, E, the whales will sing A, BBBBBBB, C, EEE, but not A, C, B, D, E. Within these themes are patterns that are transforming, as whales will leave out some of the notes. It might leave out the note at the beginning and at the end, and then the whale will go on to change it by repeating the beginning note and the end note. Eventually the sequence will transform into a whole new theme.
When male Humpback Whales (Megaptera novaeangliae) meet, songs change. The song changes as individuals begin to make modifications, which are then adopted by the rest of the population. So a few years later, you might not recognize what had become of the theme, but if you listened to all the songs in between, you could see how it transformed. The unique dynamics of the Humpback Whale song changes collectively, which means all the singers within a certain ocean basin sing the same version, and the song’s rate of change may vary by area. In Bermuda one study showed a complete turnover in five seasons. In Australia, it was two seasons.
Humpback Whale Song
The Humpback Whale song is one of the most complex in the animal kingdom. Both male and female Humpback Whales (Megaptera novaeangliae) produce sounds, such as moans, grunts, blasts, hums, whups, chirps, and shrieks, however only males produce long, complex songs for which they are famous.
Whales have no vocal cords, so they generate their song by forcing air through their massive nasal cavities. Each part of their song is made up of high and low frequency sound waves from 30 Hz to about 8,000 Hz, and these sound waves can travel more than 10,000 miles in the ocean. Whales could once communicate halfway around the world, but due to increasing noise pollution of the oceans, this is now nearly impossible.
Males generally sing during the breeding season suggesting that the purpose of the songs is to attract females, and as a warning to other males. The song is made up of repeated phrases and themes, which can last for hours, and will slowly evolve over time, making it different from year to year.
Whales within a large area sing the same song, so all of the humpbacks of the North Atlantic sing the same song, and those of the North Pacific sing a different song. Each population’s song changes slowly over time, never returning to the same sequence of notes. Researchers working together in Mexico, Japan, and Hawaii, found when the song altered slightly in Hawaii, within several days it also altered in Mexico and Japan to match the Hawaiian singers.
Hawaiian Islands Humpback Whale Report
NOAA has produced a report on the health of humpback whales within the Hawaiian Islands Humpback Whale National Marine Sanctuary. The report provides a summary of the status of humpback whales (Megaptera novaeangliae) and their related habitats in the sanctuary, pressures on those resources, current condition and trends, and management responses to the pressures that threaten the health of humpback whales and their habitat.
The sanctuary was designated to protect the humpback whale and its breeding and calving waters around the main Hawaiian Islands. This area encompasses 1,370 square miles and supports more than half of the North Pacific humpback whale population. Although their overall population is increasing in the sanctuary, their health rating is “fair” because of an increase in reported collisions, entanglements, and associated impacts.
Entanglement and whale-vessel collisions have been widely identified as the primary human cause of mortality for humpback whales, both in Hawaii and around the world. Therefore, these two issues have been identified as immediate and pressing concerns for the sanctuary. This report reaffirms why humpbacks need protection. Through management, resource protection, education, outreach, research and cultural activities, the sanctuary strives to protect humpback whales and their habitat in Hawaii.
This condition report also includes the most up-to-date information from SPLASH (Structure of Populations, Levels of Abundance and Status of Humpbacks). The SPLASH project represents the largest and most complete examination of humpback whale migrations in the world and has revealed a far more complex pattern of movements than had been previously documented. You can read the entire condition report on the health of humpback whales here.
Humpback Whale Season Ending
The first whale sighting in the Hawaiian islands for the 2009-2010 season was at the end of October, and now the time is coming to say good-bye to the humpback whales as they migrate north to Alaska for the summer. The whales need to return to cooler waters so they can feed upon the large schools of small fish that are the mainstay of their diet.
The Hawaiian Islands Humpback Whale National Marine Sanctuary is the nation’s primary mating and calving grounds for the endangered humpback whale. The population of North Pacific humpback whales has recently been increasing about five percent each year. During the Sanctuary Ocean Count in March, volunteers spotted 1,208 humpback whales off the coast of Maui.
The Pacific Whale Foundation reported three sightings of humpback whale calves without their mothers this season. Calves may be without their mothers for a number of reasons – either the mother was accidentally separated from her calf, or she abandoned the calf after deciding it had a health problem which would not allow it to reach maturity, or that the mother died shortly after birth.
Just as the whales do not arrive all at once, they do not depart all at once. Immature whales of both sexes that are still growing and not yet ready to breed usually depart early. Mature males stay here as long as mature females are around (no surprise there). Mothers and young calves are often the last ones to leave Hawaii allowing the calves grow as fat and strong as possible before making the 3,000 mile migration. Mothers will have lost nearly 10,000 pounds by the time they return to the feeding grounds.
In 2009 the last whale sighting in Hawaiian waters occurred as late as mid June.
Life – Mammals
This episode of Life
Raising young is another important factor in mammals’ success. Coatis and meerkats form social groups to share the burden of childcare. A first-time African elephant mother needs the experience of the herd’s matriarch to get her young calf out of trouble. In an astonishing sequence, an elephant grandmother shoves her inexperienced daughter aside to pull her newborn granddaughter out of the mud and save her life.
Mammals have evolved different ways of travelling long distances. Reindeer move through the Arctic tundra, making the longest overland migration of any animal. A massive colony (only recently been discovered) of ten million fruit bats congregate at Zambia’s Kasanka swamps to gorge on fruiting trees.
The largest animals in the ocean are also migratory mammals. Humpback whales in different parts of the world all migrate from cooler feeding grounds to warmer oceans for mating and raising calves. Hawaii is one of the premier places on Earth to see these magnificent creatures. Life takes you on a heat run where a female leads her potential suitors on a chase with the males battling for dominance behind her.
The video shown here is the opening sequence of the previously recorded version narrated by David Attenborough.
