Elements of ecology (1954) Elements of ecology elementsofecolog00clar Year: 1954 Efficiencies 499 represents a net production lor the herbivore equal to 2^2 pt'r cent of the food consumed. Obviously in the case of a mammal a large part of the food energy goes into heat production, and any active animal burns up considerable fuel in its locomotory activities, including foraging for food. Fish culturists have found that about 1 kg of fish can be produced for every 5 kg of meat consumed—or an efficiency of about 20 per cent for this highly digestible type of food. Measure- ments of the efficienc
Elements of ecology (1954) Elements of ecology elementsofecolog00clar Year: 1954 Efficiencies 499 represents a net production lor the herbivore equal to 2^2 pt'r cent of the food consumed. Obviously in the case of a mammal a large part of the food energy goes into heat production, and any active animal burns up considerable fuel in its locomotory activities, including foraging for food. Fish culturists have found that about 1 kg of fish can be produced for every 5 kg of meat consumed—or an efficiency of about 20 per cent for this highly digestible type of food. Measure- ments of the efficiencies of various steps in production for pond com- munities have been made by Lindeman (1942), for oceanic plankton by Riley, Stommel, and Bumpus (1949), and for certain farm crops by Transeau (1926). A schematic representation of the chief compo- nents in the ecosystem of Georges Bank, a fishing area off the coast of Massachusetts, shown in Fig. , summarizes our present knowledge of the quantitative relations involved. The blanks indicate the gaps Radiant energy: 3,000,000 gcal/day Currents Migration ^9000_g:ca/^ Fish landed Migration Currents Fig. Principal components and processes involved in production on Georges Bank, off Massachusetts. Values are averages for the whole bank per square meter of sea surface. Maximum and minimum values vi^ithin the cogwheels are for the standing crop; those over the wheels are for net production rate. Average yield during 1923 to 1945 is indicated at right. (Clarke, 1946.)
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