Surprisingly, scientists believe that cetaceans evolved from hoofed mammals, perhaps cattle, sheep or camels, about 45 million years ago. Whales underwent a series of adaptations to allow them to thrive in a marine environment, explains Earthtrust. The mammals' forelimbs developed into flippers for steering, while the hind limbs atrophied. Their tail broadened, forming two flukes or tips, which move up and down to propel them through the water. The coat of hair has transformed into a thick layer of blubber for insulation from the cold, as well as for buoyancy. Most importantly, the whales' nostrils are now located at the top of their heads. This blowhole allows them to come to the water's surface for air. Commercial whalers have always hunted humpbacks for their oil, meat and whalebone. Their numbers were seriously reduced in the early part of the 19th century, with only 5 to 10 percent of the original population left by 1986. In that year, the International Whaling Commission (IWC) instituted a moratorium on killing whales to give whale populations, including the humpbacks, a chance to recover.
Since the moratorium, a number of countries have discovered that the whale populations off their shores are more valuable alive than killed for their parts, according to The Dolphin Institute. Through ecotourism and whale-watch cruises, the public gains adventure and knowledge, while the sponsoring state or country brings in tourist revenue. Almost 1 million visitors experience humpback whale watching every year. The whale-watch industry in Alaska, Baja California, New England and eastern Canada is also lucrative. Similar cruises in the Ryukyuan Islands of Japan and off the coast of Australia are gaining in popularity. Even Norway, which noted a desire to resume commercial whaling, is now experiencing success with whale-watch programs.
Humpback whales, because of their massive size, prey on many smaller species and have few predators of their own, besides humans. Their job is to eat enough to maintain balance among the other ocean inhabitants. If too many of certain species survive, they may threaten the existence of other creatures important to the environment. At their summer feeding grounds, humpbacks consume between 2,000 and 9,000 lbs. of small fish and krill, a tiny, shrimp-type organism, per day. Much of this is stored as blubber to sustain them during their winter fast in warmer waters. Scientists in the Southern Ocean are trying to determine how much krill the whales actually down, since the krill population may decrease as commercial fishermen seek it as fish farm food and a source for omega-3 supplements, reports the "Antarctic Sun Newspaper."
After the whales have processed their daily consumption of fish and krill, their excrement, which is fluffy and floats on the water's surface, feeds tiny, floating plants called phytoplankton. Fish then eat the phytoplankton. As an example of the full-circle process of the ecosystem, whales feast on the fish, according to an article in LiveScience. A research team in the Gulf of Maine analyzed 16 fecal samples from humpback whales, which showed a rich concentration of nitrogen. Nitrogen triggers phytoplankton growth.
