Gray Whale Population example essay topic

Introduction Whale is a large mammal that lives its entire life in water. Like other mammals, whales have a large highly developed brain and nurse their young with milk. Whales resemble fish in many ways, but they are not. Fishes are cold blooded and breathe underwater using gills. Whale maintains a warm, constant body temperature of about 37 degrees Celsius (about 99 degrees Fahrenheit) and breathes underwater using lungs.

Unlike fish, whales move their tails up and down when they swim instead of moving side to side done by the fish. Whales can be found in all oceans and seas in parts of the world, rivers and lakes in Southeast Asia, South American tropics, Northern America and various other parts of the world. Whales are enormous in size compared to other mammals but at the same time, it is also one of the biggest animals living today. There are over seventy- five different species of whales and each species has its own unique characteristics. Now today, I would like to start the presentation off by talking about the different groups of whales and the different species within the groups. Since there are so many different types of whales, I would like to talk about the whales that I believed to be very important.

Whales are divided into two groups; toothed whales and baleen whales. The toothed whales have jaws lined with simple pointed teeth. These whales actively hunt fish and squid. Toothed whales vary in size from one's that are six feet long to the great sperm whales that average fifty-five feet in length and can weigh nearly fifty metric tons. Among the more unusual toothed species are the narwhal and the beluga, which both inhabit the Arctic waters.

From the toothed whales, I will be talking about the beluga whale. The second group known as baleen whales, instead of having teeth, they have mouths lined with giant flexible combs of a material called baleen, or whalebone which is used to filter small fis from the water. There are three types of baleen whales: the rorquals, the gray whales and the right whales. From this group I would like to talk about the southern right whale, northern right whale, bowhead whale, gray whale, blue whale and humpback whale. The reason why I chose these whales is because they are listed either as an endangered or vulnerable species.

Beluga Whale The beluga whale is a small, toothed whale that is white as an adult. Belugas have a small blunt head with small beak, tiny eyes, and a thick layer of blubber. Beluga means white one in Russian. The beluga is also called the white whale. Beluga whales grow to be about 15 feet long on average and weighing about 3300 pounds. Beluga whales are social animals that tend to hunt and migrate in pods- groups consisting of about ten whales.

Belugas live in frigid Arctic and sub- Arctic waters, but some populations migrate south to warmer water in the summer. Belugas at the same time also travel up northern rivers into brackish (partly salty) water to hunt prey. Killer whales and polar bears prey on belugas, especially the calves. People have hunted for belugas for hundreds of years but now only a few Arctic tribes hunt for them. It is estimated that there are about 40,000 to 80,0000 beluga whales worldwide. Although there are many still left, the St. Lawrence, Cook Inlet, and Alaskan belugas are classified as endangered.

The St. Lawrence belugas are critically endangered with only about 700 remaining. The St. Lawrence belugas are a victim of shipping disturbance including collisions, noise pollution, habitat degradation, and above all toxic contaminants. The beluga is so contaminated by DDT and PCB's that dead carcasses have to be disposed of as toxic waster. Humpback Whale The humpback whale is one of the rorquals, a family that includes the blue whale, fin whale, sei whale and the minke whale. The shape and color pattern on the humpback's dorsal fin and fluke tail are different for each whale so it is similar to fingerprints of human.

Because of this, new form of research known as photo- identification was made. Each whale is identified, catalogued and monitored so this gives researchers valuable information about humpback whale population, migration, sexual maturity and behavior patterns. Adult humpback measure 40 to 48 feet in length and weigh about 30 tons. Humpback whales are found in all the world's oceans. Most populations of humpback follow a migration routine, summering in temperate and polar waters for feeding and wintering in tropical waters for mating.

Because their mating, feeding and calving grounds are close to shore, they were the target for early hunters. But in 1966, the IWC- International Whaling Committee gave them worldwide protection. At present, there are about 15,000 humpback whales living, which is around 15% of the original population. Blue Whale The blue whale is also one of the rorquals. On land an animal the size of a blue whale would be crushed by its own weight without the support of large heavy bones. But because its body is supported by water, there were no needs for such large supporting bones.

Also with the availability of large food supply have made it possible for blue whale to reach an enormous size. This is why the blue whale is the largest animal ever to live. Blue whales are scattered all over the world but the northern and southern populations do not mix. They migrate to temperate waters from their polar feeding grounds at different times of the year. The blue whales was nearly exterminated until it received a worldwide protection from the IWC in 1967.

Most of the remaining blue whales are known as Pygmy blue whales while there are about 400 true blue- whales- ones that can be 100 feet in length- that shows no sign of recovery. It is said that approximately 5000 blue whales survive today in three primary locations; North Atlantic, North Pacific, and the Southern Hemisphere. Right Whale There are two groups of right whales. The first group is the Northern Right whale, which has the title of the most endangered great whale with less than 1000 existing. Northern right whale has shown no signs of recovery since the whaling days despite full protection from hunting by a League of Nations agreement in 1935. Some believe that eastern north Atlantic population may already have become extinct while western North Atlantic population has as many as 300 remaining.

The other right whale, the Southern right whale lives only in the southern hemisphere and never mixes with northern right whale. Southern right whales mate during the winter in the inshore waters of Chile, Argentina, Brazil, Africa, Southern Australia, and other southern islands then migrate to water near Antarctica to feed during the summer. Southern right whale have the status of vulnerable with about 1500 to 4000 remaining. The most serious threats to right whales survival today are the collision with ships and entanglement in fishing gear. In 1999, there was one known death from each of these causes. Right whales are 35- 60 feet in length and weigh about 50 tons.

Bowhead Whale The bowhead whale is also known the Greenland right whale and is similar to Northern right whales but a little different. It received its name from the high arched lower jaw that resembles the shape of an archer's bow. Bowheads live at the southern edges of the Arctic during winter and moves into areas with melting ice during summer. Found only in Arctic and sub Arctic water, the bowhead has a massive body, which is protected by two feet thick blubber.

As an adult, it can be fifty feet long and weigh 60 tons. Bowhead usually travels alone unless they are in the feeding ground. It is said that one bowhead can yield up to 100 barrels worth of oil and 1500 pounds of baleen (whalebone). At present, the number of bowhead is estimated around 6000. Gray Whale Gray whales are coastal whales that migrate along the North American Pacific coast between arctic seas and the lagoons of Baja California, Mexico. Frequently visible from shore, gray whales provide a unique opportunity for land and boat observation, and commercial whale watching has become a major industry along its migration route.

Gray whales are known to be friendly and closely approaches small boats so that it can be touched by humans. The gray whale receives its name from the gray patches and white mottling on its dark skin. Adult gray whales measure 45 feet and weigh about 40 tons. Killer whales are a cause of many gray whale deaths and many gray whales have killer whale teeth scars on their body. At one time, there were three gray whale populations. A north Atlantic population now extinct, possibly the victims of over- hunting.

Eastern north pacific population which is the largest surviving population. And North Pacific gray whale population which has made a remarkable recovery and there are about 19000 of them today. Total population of gray whales today is around 25,000. This is the end of my presentation and my partner Yoo hei will now talk about whaling. 314.