. California fish and game. Fisheries -- California; Game and game-birds -- California; Fishes -- California; Animal Population Groups; Pêches; Gibier; Poissons. STRIPED BASS FISHERY 15 The changes in angling methods in San Francisco Bay have already been noted as a factor causing biases during the current period. Calhoun (1949) and Chadwick (1962) used fall catches in Blocks 301 and 308 and yearly catches in Block 303 as measures of trends in population size. Effort in Block 303 has become so insignificant that it no longer provides a useful index. Catcli rates have declined through the curre
. California fish and game. Fisheries -- California; Game and game-birds -- California; Fishes -- California; Animal Population Groups; Pêches; Gibier; Poissons. STRIPED BASS FISHERY 15 The changes in angling methods in San Francisco Bay have already been noted as a factor causing biases during the current period. Calhoun (1949) and Chadwick (1962) used fall catches in Blocks 301 and 308 and yearly catches in Block 303 as measures of trends in population size. Effort in Block 303 has become so insignificant that it no longer provides a useful index. Catcli rates have declined through the current period in Blocks 301 and 308 in the fall (Figure 8), but the change in migration patterns and the initiation of a sizable sturgeon fishery undoubtedly have contributed to this decline. >- < O z < UJ Q. </) Q Z o OL z < 15 lO 5 -. BLOCK 488 o- ALL INLAND BLOCKS 57 58 59 60 61 62 63 64 65 66 67 YEAR FIGURE 8. Three-year moving average of mean pounds per angler day for full-day party boats (based on 3-year moving average of mean weights reported and 3-year moving average of mean catch per angler day). The size of bass in the fishery also provides information on popula- tion trends, although weights have to be used even more cautiously than numbers because they are estimates rather than counts. The differences in mean weights reported for half-day and full-day boats in Blocks 301 and 308 suggest biases in reporting. However, several sources indicate the general observed trend of increasing weight is real. One source is that mean weights of bass caught in gill nets during tagging operations in the Delta have increased and agree closel}^ with reported mean weights from Block 488 (Table 6). Another source is the increase in size of fish in the party boat fishery has been paralleled by a similar increase in the Delta fishery from 1959 to 1965 (Miller and McKechnie, 1969). Tlie increase in the Delta was due to an increase in the average age of bass in the catch (Mille
Size: 2688px × 930px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorcaliforniadeptoffishandgame, bookauthorcaliforniafish
