Nature Notes

Vol. X September, 1932 No. 9

Fish Food

Fish Food

Let us turn for a moment to a phase of natural history that is beneatht the notice of the average student of nature and only dimly suspected by his companion of the outdoors, the fisherman. I refer to the tiny, microscopic life that teems in the small alpine lakes on the slopes of "The Mountain"; life of apparently no importance whatsoever to man, but, nevertheless, to the finny population, a matter of life and death - or daily bread. Most of the living material is composed of one-celled plants, too small to be seen with the naked eye, while the rest consists of larger animals that may reach the size of a grain of wheat. To such a group of free-floating, aquatic organisms, science has applied the term "plankton", from the Greek word meaning to drift.

As to the dependance of fish upon plankton, the first chapter in the story is enacted by plant cells, the prime source of food materials built up from volcanic materials and dissolved gases in the water under the activating influence of the brilliant alpine sunshine. This activity goes on not only in the summer, but also in the winter under the ice. Hundreds of these plants are diligently gathered and eaten by larger animals, chiefly members of the Crustaceae, or crab and lobster family, and these in turn become the prey of fish - both large and small.

Thus, in a 'round-about way, the energy of the sunshine is converted into the brilliant colors of the Cut-throat Trout that leaps for the fly of the fisherman. A knowledge of the relationship between plankton and fish growth explains why fish thrive in certain lakes but not in others of apparently the same structure, yet lacking in certain elements vital to plant growth.

Fish Food

In approaching the study of plankton of lakes, the scientist uses few tools. Of most use is a long, cone-shaped net of bolting silk with meshes so fine that 200 of them occupy one inch. This net is dragged slowly through the water behind the rowboat, and gradually becomes clogged with tiny plants and animals. When placed under a microscope, the wriggling catch is seen to consist of many kinds of organisms - some of intricate design and brilliant color. When one particular kind is particularly abundant, the water itself may take on a hue of green, brown, or red. Plankton hauls that have been made in Reflection Lake show an interesting lot of fauna and flora; not perhaps as abundant as that found in lakes at lower elevations, but more varied in the character of its population. Especially noticeable are thick-bodied crustaceans that form a favorite item in the fare of the mountain trout.

Victor Scheffer,

The Diet of the Bear

The diet of the American Black Bear on Mount Rainier has always been a source of wonder to the writer because of the amazing variety. In simple terms, the bear is the hog of the park, and will eat anything not definitely injurious to his system. The following observation records may serve to bring out the wide range of Bruin's apetite.

Wild plants:- on the whole almost any green vegetation except coniferous trees. (1) Roots and bulbs; Skunk Cabbage and Avalanche Lily. (2) Flowers; Valerian and Avalanche Lily. (3) Berries; Huckleberry, both leaves and fruit, Salmon berry, and Wild Blackberry. (4) Grass; bears have been observed grazing like horses on bunch grass. (5) Fungi; Mostly fleshing varieties found in late fall.

Wild animals:- a minor portion of the diet. (1) Insects; wild bees and honey, yellow jackets (droppings have been found containing a large number of these insects), ants, beetles, and larvae. (2) Larger animals; shrews and mice in rotten logs, frogs (seldom), birds and eggs in the nest, and fish.

Human foods:- anything, fresh or spoiled, in storeroom or garbage can. Apples, watermelon rinds, etc., canned goods (bears become adept at crushing milk cans and holding them aloft to drain). Bears devour much miscellaneous material - one consumed a goodly portion of a sack of commercial fertilizer destined for the golf course.

Victor Scheffer, Ranger-Naturalist

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