File:California fish and game (20325572498).jpg

Title: California fish and game
Identifier: californiafishga64_2cali (find matches)
Year: [1] (s)
Authors: California. Dept. of Fish and Game; California. Fish and Game Commission; California. Division of Fish and Game
Subjects: Fisheries -- California; Game and game-birds -- California; Fishes -- California; Animal Population Groups; Pêches; Gibier; Poissons
Publisher: (San Francisco, etc. ) State of California, Resources Agency, Dept. of Fish and Game
Contributing Library: California Department of Fish and Game
Digitizing Sponsor: Internet Archive

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ANALYSIS OF TRAWL CATCHES 113
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FIGURE 4. Trellis diagram comparing the fish catches taken in Area 3 in 1971 with those taken in the same area in 1972. A black square represents a coefficient of community of 50 or more, a blank square one of less than 50. It should be pointed out that not all changes in the specific composition of fish catches are detectable by this technique. Thus, the replacement of the species found only in one sample with species which are also unique to a subsequent sample will not alter the coefficient of community obtained when both are compared to a third sample. Reference must then be made to species lists to detect this kind of change. An attempt was made to determine the adequacy of the otter trawl as a sampling device by comparing the cumulative number of species caught to the number of hauls made in each of the study areas (Figure 6). In Area 1 the frequency with which additional species were being caught decreased markedly after 15 hauls were made, although a few additional species continued to be obtained up to the 50th and last haul made in the area. Forty-eight species of fishes were caught in this area. In Area 2, a similar trend can be seen, although only six additional species were caught subsequent to the first 15 hauls. Forty-

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