Are beluga whales disappearing?
(2006-2007学年第32期)
Belugas appear to be thriving across the Arctic, with an estimated population of 40,000 in 2005. However, in Alaska’s Cook Inlet beluga numbers have been plummeting, worrying wildlife officials and puzzling scientists. Last year the Cook Inlet population was below 300, more than a 75-percent drop from a high of 1,300 in the late 1970s.
Scientists have been examining noise pollution from shipping and recreational boating as one potential culprit. Waste discharges and development in and around the inlet could also be to blame.
The result has been a restriction on how many belugas Alaskan Native subsistence hunters can harvest.
Wildlife officials have set the individual limits so low — one or two per year, to a total of eight through 2009 — that the population should be growing, but it’s not. A status review is under way to determine whether belugas need protection under the Endangered Species Act.
Belugas live in coastal waters of the northern Arctic. Adults can grow to as long as 16 feet and weigh more than 3,000 pounds, with life spans as long as 50 years. Other than their white color, the most striking physical feature of belugas is the absence of a dorsal7 fin(鳍).
Bertha the beluga, a story
Once upon a time in a frigid land of ice and snow, there lived a pleasant beluga named Bertha. Bertha was born after her mother, Bessie, held her within the confines of her womb(子宫) for 15 months, in which she playfully swam with other pregnant mothers as they prepared to welcome the next generation into the sea. During this time, Bertha’s father, Bartholomew, was having meetings with the other fathers in the open sea.
On the warm spring morning that Bertha was born, Bartholomew and the other fathers protected the expectant mothers that all lived in a shallow estuary off of Baffin Bay(巴芬湾). Bertha was born a brownish-grey colour, weighing 50kg and measuring 1.5 metres in length. When she was born, Bertha came out of her mother’s womb tail first, in shallow, warm waters, near the surface of the ocean. Her umbilical cord(脐带) quickly snapped away from her mother and she was finally released into the waters of her new icy life. Bertha was free to swim up to the water’s surface to take her first breath — with her mother’s help, of course. Bessie and Bertha stayed close as Bertha nursed milk from her mother’s abdomen(腹部). This close relationship continued until Bertha’s first birthday, when her teeth began to form.
After Bertha’s teeth became fully formed, she was free to go out hunting to catch her own food all by herself, without her family’s help. Usually this hunting job was taken care of by her older brother, Benjamin, but today was Bertha’s turn to learn (just in case). On one bright, adventurous morning, Bertha set out with her best friend, Betty, in search of some food for lunch.
As the two whale friends traversed the cool coastal waters of their home, they kept watch for any unsuspecting mollusks(软体动物), fish, or benthic invertebrates(无脊椎动物) that crossed their paths. Suddenly, Betty spotted Mark the mollusk swimming with a few of his friends. Utilizing great stealth, Bertha and her friend managed to sneak up on Mark from behind and gobble him and his friends up for a most appetizing lunch.
Satisfied by her accomplishments, Bertha set off on the journey home. However, this adventure was tainted with peril. While swimming around a bend on her way to the home estuary, Bertha encountered Kenneth, the Killer Whale. With a menacing grin, he set off at full speed toward Bertha, determined to gobble her up for HIS lunch. Ever so smooth, Bertha managed to quietly swim behind an ice floe and with her bluish white skin, camouflaged by the frigid obstacle. She arrived home safely, with many stories to account to her fellow Beluga whales.
As Bertha began to mature into a grown up Beluga, her colouring gradually turned from a bluish-brown, grey colour into the pure white of an adult Beluga. By the time she was five years old, Bertha the Beluga weighed 1,360 kg, measured 4 metres in length and was considered a sexually mature adult. Bertha was now able to search for a male with whom she could start a new generation of whale families. At the age of 28, after living a long, prosper-ous, and fulfilling life, Bertha passed away peacefully, with the hope that humans learn to protect their environment and respect the animals that they share it with (especially the Belugas)