Page 234 - NS-2 Textbook

OCEANOGRAPHY 229

Unlike baleen whales, toothed whales have teeth after
birth. TI,ese teeth number from just a few in some species
to as many as 250, although some may be concealed be-
neath the gum. The narwhal has a single long, tusklike
tooth in the upper jaw. Toothed whales have one blow-
hole, in contrast to the baleen, which have two. This
group includes the animals commonly called dolphins or
porpoises, as well as sperm whales. The sizes in this class
range from the porpoise, which is about 5 feet long, to
the sperm whale, which is up to 68-70 feet long. TIley eat
fish prinlarily, but the sperm whale also likes giant squid
found at great depths. Records of sperm whales being
entangled with submarine cables at depths to 3,700 feet
indicate that some of the squid on which they feed are
browsing on the bottom. Japanese fishermen take aboard a load of fresh-caught Alaskan
king crabs in the Bering Sea north of the Aleutian Islands. The U.S.
Coast Guard Bering Sea Patrol enforces the North Pacific fishing
LIFE IN THE OPEN OCEAN treaties within 200 miles of the Alaskan coast.

Beyond the shallow waters of the continental shelf, there in some phase of the marine fishing industry worldwide.
is much less sea life because there is little plant life. Food The armual worldwide consumption of fish and fish prod-
is scarce. The animals of the region come to the surface to ucts from all sources is some 120 million tons. Of this, some
feed on the limited zooplankton and smaller fish, but in 20 percent comes from aquaculture (fish farming). The re-
general, food is hard to find. maining 80 percent comes from fishing in the world's
We talked earlier of the Sargasso Sea in the central oceans and inland waters. Of this, about 55 percent comes
Atlantic. Here there is a great deal of floating salgasslll1l from fue Pacific, 20 percent from the Atlantic, and fue rest
weed, which gives the area its name. This weed floats from fue other world oceans and inland waters.
near the surface in clumps, plainly visible to sailors tra- The amount of seafood eaten armually in different
versing the area. With the exception of this weed, the parts of the world is related to eating habits that people
water of the Sargasso Sea is about the purest and clearest have developed over centuries and the local standard of
salt water in the world. In fact, as sea life goes, there is lit- living. For example, in a recent year in the United States,
tle life other than the tiny shrinlp, fish, and crabs that live each person ate an average of only about 15 pOlU1ds of
among the tangle of sargassum. Limited phytoplankton fish and other seafoods. In Japan in the same year, the av-
live in the area because there is almost no upwelling of erage person consumed over 80 pounds. Many other
nutrients from the deep sea bottom. people, especially in underdeveloped countries, may eat
On the edges of the currents of the sea live many of more than that, usually in the form of fish-meal cakes
the great game fishes of the world, such as marlin, sail- purchased from major commercial fishing nations.
fish, tuna, and sharks. Especially good fishing grounds The history of fue fishing industry is part of fue evolu-
for these fish are on the fringes of the Gulf Stream along tion of world commerce and the never-ending searm for
the eastern seaboard and on the Mexican coasts in both food. Since the beginning of fue twentieth cenhuy, many
the Atlantic and Pacific. Tuna species are found through- inlprovements in fishing vessels, nets, and preservation
out the world ocean as they follow the plankton commu- methods have occurred. Progress made in fishing methods
nities and migrate to central ocean spawning grounds. since 1930 alone has been greater than that made in the pre-
TI,ere are places on a continental 01' island shelf vious three thousand years. TIrree main types of new ves-
where the ocean floor rises much closer to the surface in sels have been developed: the giant plIl'se seiner, a vessel
high lU1derwater plateaus. These areas have an abun- that uses sonar equipment to locate and entrap schools of
dance of marine vegetation for fish to feed on. TI,ese fish; the oceanic IOllg-lillers, which can fish for tuna
plateaus are called banks. TIley are the best fishing tluoughout the tropical oceans; and fue jac/ory trawlers.
grounds in the world: the Grand Banks off Newfollild- The large purse seiners were designed by Americans
land, Georges Bank off Massachusetts, the Dogger Bank to pursue tuna on the high seas. They are based in Cali-
in the North Sea, and in the Pacific near Japan and Alaska. fornia but cruise the world. Their large nets can catch a
whole school of tuna at one set. Many of the larger ships
can carry 1,500 tons of frozen fish in their holds.
THE FISHING INDUSTRY
The long-liners originated in Japan and South Korea.
According to a recent United Nations report, some 3.8 mil- These vessels layout from one to three floating long-
lion vessels of all sizes and 30 million people are engaged lines, each more than 20 miles long and bearing baited