Salmon studies in interior Alaska, 1998
By: by Lisa Stuby.
Contributors: Alaska. Division of Sport Fish.
Series: Fishery data series -- no. 99-13.
Publisher: Alaska Dept. of Fish and Game, Division of Sport Fish, Research and Technical Services
Published: 1999
Place of publication: Anchorage
Language: eng
Number of pages: 79
Subjects: Salmon -- Alaska, Interior -- Statistics.; Fish populations -- Alaska, Interior -- Statistics.; Fishes -- Alaska, Interior -- Statistics.
Description: Escapements of chinook salmon Oncorhynchus tshawytscha in the Salcha, Chena and Chatanika rivers near Fairbanks, Alaska were estimated using tower-count methodology. The counts were conducted from 26 June to 9 August for both the Salcha and Chena rivers, and 7 July to 31 July for the Chatanika River. Tower-count estimates for chinook salmon were 5,027 (SE=331) for the Salcha River, 4,745 (SE=503) for the Chena River and 864 (SE=74) for the Chatanika River. Aerial survey counts of chinook salmon during the periods of maximum escapement were 1,992 for the Salcha River and 386 for the Chena River. These estimates were 0.40 of the Salcha River tower estimate, and 0.08 of the Chena River mark-recapture and tower estimate. Females comprised 0.30 (SE=0.04) of a sample of chinook salmon carcasses collected in the Salcha River during late August. For the Chena and Chatanika rivers, females comprised 0.40 (SE=0.03) and 0.33 (SE=0.06) respectively. The majority of males examined from the Salcha River were age 1.3 (0.76), with the rest comprising ages 1.1 (0.03), 1.2 (0.07), 1.4 (0.13), and 1.5 (0.01). For the Chena River, the majority of males were age 1.3 (0.86) with the rest comprising ages 1.2 (0.07), 1.4 (0.04), and 1.5 (0.02). The majority of females were age 1.3 (0.65) for the Salcha river with the rest comprising 1.4 (0.30) and 1.5 (0.05). For the Chena River, females were 1.3 (0.53), 1.4 (0.38), and 1.5 (0.09). The majority of females were aged 1.4 (0.44) for the Chatanika River with the rest comprising 1.2 (0.06), 1.3 (0.39), and 1.5 (0.11). For the three rivers, age and sex ratios have varied over the years since the inception of carcass surveys. A portion of the Salcha, Chena and Chatanika rivers chum salmon Oncorhynchus keta escapement was also estimated during the tower-counts. Estimated escapement of chum salmon was 17,289 (SE=696) for the Salcha River and 5,901 (SE=342) for the Chena River. Estimated escapement of chum salmon was 663 (SE=100) for the Chatanika River. Escapement of coho salmon Oncorhynchus kisutch was measured in the Delta Clearwater River near Delta Junction, Alaska, by means of aerial and boat-counts. The boat-count of the mainstem river was 11,100 on 20 October, and the helicopter count on 21 October of tributaries was 2,775. Total escapement was estimated to be 13,875. A total of 221 coho salmon were sampled for age, sex and length. Females comprised 0.51 of total fish sampled. Eighty-three percent of the total coho salmon sample were age 2.1. Since 1990, 2.1 has been the predominant age group for the Delta Clearwater River coho population sampled.
Notes: "August 1999."

Includes bibliographical references (p. 59-62).

Also issued online.