Movements, food availability and stomach contents of northern pike in selected Susitna River drainages, 1996-1997
By: by David S. Rutz.
Contributors: Alaska. Division of Sport Fish.
Series: Fishery data series -- no. 99-5.
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: 68
Subjects: Pike -- Alaska -- Susitna River Basin -- Statistics.; Pike -- Food -- Alaska -- Susitna River Basin.; Fishes -- Alaska -- Susitna River Basin -- Statistics.; Fish populations -- Alaska -- Susitna River Basin -- Statistics.
Description: Four tributaries within the Susitna River drainage were sampled during 1996 and 1997 to assess movement, mean length, availability of food items, and stomach contents of northern pike Esox lucius. Movements of northern pike were investigated using radiotelemetry. The greatest distance a radio tagged fish traveled from capture location was 10 km; the least distance traveled was less than 1 km. Nearly all northern pike remained within the drainages where they were originally captured. Many of the radio tagged fish moved between sloughs and lakes within drainages, while only one incidence of movement was observed between drainages. We analyzed the stomach contents of northern pike captured in four selected Susitna River drainage systems to assess differences in food availability and items in the diet of northern pike. Of the 389 stomachs examined, 249 (64%) were non-empty. Of the 249 non-empty stomachs examined, 198 (80%) contained salmonids, 4 (2%) contained invertebrates, and 17 (7%) contained threespine sticklebacks Gasterosteus aculeatus. All five species of pacific salmon Oncorhynchus were observed in northern pike stomachs. Salmonids present in northern pike stomachs by species in order of magnitude were: coho salmon O. kisutch (59%), sockeye salmon O. nerka (24%), rainbow trout O. mykiss (6%) chinook salmon O. tshawytscha (3%), chum O. keta and pink salmon O. gorbuscha (<1%). We set 290 minnow traps in the same four Susitna River tributaries. Equal proportions were set in locations of confirmed radio tagged northern pike signals, primarily within side sloughs and within the adjacent creek proper. Catch per trap for the traps fished near locations of confirmed radio tagged northern pike were lower for salmonids (0.4 fish/trap) and higher for sticklebacks (30.6 fish/trap), while conversely, catch per trap for the traps fished within the adjacent creek proper was higher for salmonids (10.4 fish/trap) and lower for sticklebacks (8.3 fish/trap).
Notes: "May 1999."

Includes bibliographical references (p. 22-24).

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