Biological characteristics of the gill net catch from the 1988-89 Pacific herring, Clupea harengus pallasi, roe fishery in California
1989
Spratt, Jerome D.
In Tomales Bay, 4-, 5-, and 6-yr-old herring, Clupea harengus pallasi, comprised 83% by number of the 1988-89 season's gill net catch.Recruitment of the 1985 year class (4-yr-olds) was relatively good, comprising 22% of the gill net catch by number.Average length of the Tomales Bay gill net catch decreased to 197 mm BL because the percent of 3- and 4-yr-olds in the catch doubled over the 1987-88 season.Average weight of 4- through 8-yr-olds returned to normal this season, reversing a downward trend.The origin of the Tomales Bay catch this season changed to Bodega Bay, and the possibility that the catch may be from a different stock must be considered.In San Francisco Bay, 4-, 5-, and 6-yr-old herring comprised 81% by number of the gill net catch; average length of the catch stabilized at 195 mm BL.A subtle gear change this season is believed to have resulted in very little change in the San Francisco Bay catch characteristics. A lighter monofilament that stretches easily was used in gill nets this season. This type gear effectively lowered the mesh size of many gill nets to 2 in. These gill nets technically were legal (2 1/8 in.) whenmeasured because they stretched easily. (18pp.)
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