Stock assessment of whitefish in the Chatanika River during 1996 and 1997
By: by Douglas F. Fleming.
Contributors: Alaska. Division of Sport Fish. Statewide Research and Technical Services Unit.
Series: Fishery data series -- no. 97-36.
Publisher: Alaska Dept. of Fish and Game, Division of Sport Fish, Research and Technical Services
Published: 1997
Place of publication: Anchorage
Language: eng
Number of pages: 33
Subjects: Whitefishes -- Alaska -- Chatanika River -- Statistics.; Least cisco -- Alaska -- Chatanika River -- Statistics.; Fish populations -- Alaska -- Chatanika River -- Measurement.
Description: In 1996, 623 humpback whitefish Coregonus pidschian 360mm FL and 529 least cisco C. sardinella 290mm FL were sampled from a 30 km section of the Chatanika River during August and September. The August sampling period corresponded to the timing of 1992-1994 assessments, while the September sampling corresponded to the time when the sport spear fishery was open to exploitation (prior to 1994). Ages 4, 5 and 6 predominated in humpback whitefish indicating strong pre-recruit classes; ages 4, 5 and 6 also dominated in least cisco, however the younger age classes (ages 2 and 3), normally vulnerable to sampling gear, were low in abundance. Significantly fewer age 4 humpback whitefish were sampled in September than in August (2 = 25.38, df = 11, P=0.008). There was no significant difference among the August and September age samples for least cisco. In 1997, we conducted a mark-recapture experiment in a 53 km (33 mi) section of the Chatanika River from August 20-28 to estimate abundance and stock composition of both species. The investigation was timed to correspond to the upstream spawning migration of both species, and to provide in-season estimates of abundance prior to the timing of a recreational spear fishery. An estimated 16,107 (SE = 1,260) humpback whitefish ( 360 mm FL) were present in the study area. The assessed stock was characterized by a high proportion of humpback whitefish between 390 and 430 mm FL with ages 5, 6, and 7 predominating. An estimated 22,811 (SE = 4,496) least cisco ( 290 mm FL) were present in the study area. The assessed least cisco stock was predominated by age 5 and 6 fish, and primarily comprised of fish greater than 340 mm FL. Poor recruitment within the least cisco stock was indicated by the age composition, and estimated recruitment levels of age 3 fish were the lowest in 11 years of stock assessment.
Notes: "November 1997"

Includes bibliographical references (p. 29-31).

Also issued online.

Partially financed by the Federal Aid in Sport Fish Restoration Act (16 U.S.C. 777-777K) Project F-10-12 and F-10-13, Job(s) no. R-3-5(a).