Lower Yellowstone River fishery study : final report /

Haddix, Michael H.; Estes, Christopher C.

doi:10.5962/bhl.title.130174

Cited by 1 publication

(2 citation statements)

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“…Relatively low exploitation (15-20%) and high survival (68-73%) rates were observed. High survival rates were corroborated by the lengthdetermined age structure of saugers collected for this study; about half of the tagged fish were 5-10 years old (Haddix and Estes 1976;Carlander 1997). High proportions of old fish are characteristic of lightly exploited stocks (Van Den Avyle and Hayward 1999).…”

Section: Discussionsupporting

confidence: 54%

“…In 2003, saugers were only collected directly downstream of the Powder and Tongue rivers to explicitly assess tributary use. Only sauger adults, as determined by lengths greater than 350 mm or the expression of gametes, were used (Haddix and Estes 1976;Carlander 1997). We used radio transmitters of two sizes to maximize battery life while avoiding transmitter-to-body-weight ratios in excess of 2% (Winter 1996).…”

Section: Methodsmentioning

confidence: 99%

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Seasonal Movements, Habitat Use, Aggregation, Exploitation, and Entrainment of Saugers in the Lower Yellowstone River: An Empirical Assessment of Factors Affecting Population Recovery

Jaeger

Zale

McMahon

et al. 2005

N American J Fish Manag

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Migratory barriers, habitat loss, entrainment in irrigation canals, and overexploitation, especially at times of aggregation, have been suggested to explain the failure of Yellowstone River saugers Sander canadensis to return to historical abundances after a late-1980s decline that was attributed to drought. These factors are thought to affect saugers throughout their range and migratory large-river fishes in general. We characterized the seasonal movement patterns, habitat use, and aggregation of saugers and estimated movement, exploitation, and irrigation canal entrainment rates to test these hypotheses. Saugers aggregated near spawning areas in spring and subsequently dispersed 5-350 km to upstream home locations, where they remained for the rest of the year. Upstream movement was not overtly restricted by low-head diversion dams. During the spawning period, terrace and bluff pools, which are unique geomorphic units associated with bedrock and boulder substrate, were positively selected, while all other habitat types were avoided. Tributary spawning was rare. After moving to home locations, saugers used most habitat types in proportion to their availability but selected reaches in specific geologic types that allowed formation of deep, long pools. Exploitation occurred primarily in early spring and late autumn, was low annually (18.6%), and was not related to aggregation. Annual survival was high (70.4%). Entrainment in one irrigation diversion accounted for more than half of all nonfishing mortality. Therefore, habitat loss and overexploitation probably did not prevent sauger recovery, as the absence of migratory barriers allowed adult saugers unrestricted access to widely separated and diverse habitats and did not induce artificial aggregation. In other systems, population declines attributed to overexploitation during periods of aggregation may therefore have been caused fundamentally by migration barriers that created artificial aggregations.

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Section: Discussionsupporting

confidence: 54%

Section: Methodsmentioning

confidence: 99%