ASPECTS OF HONG KONG MARINE FAUNA
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arrow worm is found in it. Light is another important factor, for only the blue end of the spectrum penetrates much beneath the surface of the water. This means that at only a few feet below the water's surface, blues and greens are the predominant colors, and lend an ethereal background to submarine photographs, unless artificial light is employed. Other factors, such as pressure, depending on depth; available nutrients, or food sources; and the type of bottom on which the organisms living in a particular habitat are found, are also important factors.
The focus of tropical marine fauna in the Pacific Ocean centers around Indonesia, and spreads widely to include the Indian Ocean, Red Sea, the South Pacific, and north to Hawaii, and is thus called the Indo-Pacific marine faunal realm. Variety is great in this realm, but representatives of most marine groups can be found in areas anywhere in the region. The fauna of Guam, in the Marianas Islands, is thus similar to that of the Great Barrier Reef of Australia, or that of the Seychelles Islands in the Indian Ocean.
Many marine organisms associate with one another, often in most peculiar ways. In some areas of the world, pearlfishes, which are my own specialty, live inside the body of sea cucumbers*. Some species of pearlfish are parasites, while others only use the body of the sea cucumber as a house, coming out into the open sea at night to feed. Clownfishes are another example. They often live in the folds of sea anemones. Although the clownfish is not harmed, other fishes approaching the anemone are stung by poison-filled threads, quickly die, and the clownfish and anemone share the meal.
Marine biology is thus a fascinating field of study in which great advances are constantly emerging. Its importance, with over 2/3 of the world covered by oceans, is becoming quite evident.
Marine Conditions in Hong Kong
Let us turn our attention back to Hong Kong. Having seen the importance of temperature to marine creatures, perhaps a look at the temperature ranges found throughout the year in Hong Kong would be beneficial. A graph plotting the average
* Trott, 1970.