Hungry Horse Dam Fisheries Mitigation; Kokanee Stocking and Monitoring in Flathead Lake, 1996 Progress Report.

Fredenberg, Wade; Hansen, Barry; Deleray, Mark

doi:10.2172/544744

Cited by 3 publications

(6 citation statements)

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“…Although lake trout probably were increasing slowly in abundance since their introduction in 1905 (Spencer et al 1991), M. relicta appears to have facilitated the strong lake trout population expansion through improved survival of the young fish. Apparently, the expanded lake trout population is largely responsible for the kokanee declines in Flathead Lake (Carty et al 1997), although the decreased populations of large zooplankton also need to be considered (Beattie and Clancey 1991;Spencer et al 1999). Further, we strongly suspect the lake trout expansion is at least partially responsible for the bull trout declines post.…”

Section: Discussionmentioning

confidence: 99%

“…Lake trout have replaced bull trout as the dominant piscivore in Flathead Lake and compete heavily with bull trout in other systems (Donald and Alger 1993). Predation by the expanded lake trout population is also impacting the abundance of fishes in the lake, particularly kokanees (Carty et al 1997), which have virtually disappeared from the lake despite a substantial stocking effort.…”

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confidence: 99%

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Changes in Lake Trout Growth Associated withMysis relictaEstablishment: A Retrospective Analysis Using Otoliths

Stafford

Stanford

Hauer

2002

Transactions of the American Fisheries Society

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The establishment of the opossum shrimp Mysis relicta in Flathead Lake, Montana, was followed by a dramatic increase in the population of lake trout Salvelinus namaycush. Using otoliths, we compared lake trout growth before and after the arrival of M. relicta. The widths of annual increments 1-3 were similar, but width generally declined in increments 4-10 after the establishment of M. relicta. To calculate body size in the post-M. relicta fish, we used the relationship between body length and otolith radius. To retrospectively calculate body length for the pre-M. relicta fish (for which we lacked body sizes), we developed a simple empirical correction to account for the conservative nature of otolith growth rate relative to body growth rate.

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Changes in Lake Trout Growth Associated withMysis relictaEstablishment: A Retrospective Analysis Using Otoliths

Stafford

Stanford

Hauer

2002

Transactions of the American Fisheries Society

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“…However, total lake trout consumption exceeded our estimates of pelagic fish biomass in these reservoirs, strongly implicating lake trout predation as a contributing factor in these kokanee declines. Lake trout predation has been implicated as a threat to prey fish populations (including kokanee) in several other western lakes and reservoirs (Bowles et al 1991;Rieman and Myers 1991;Yule and Luecke 1993;Beauchamp 1996;Carty et al 1997;Ruzycki and Beauchamp 1998). In Lake Granby, relative weights (Piccolo et al 1993) of large lake trout have decreased by about 2% per year since 1986, concomitant with the decline of a major kokanee fishery (Figure 8a).…”

Section: Discussionmentioning

confidence: 99%

“…Chronic shortages in the kokanee egg supply in the western United States (Martinez 1995) preclude satisfying hatchery needs with eggs from other sources. Further, lake trout predation has frustrated efforts to reestablish kokanee in Flathead Lake through stocking (Carty et al 1997). Although harvest regulations for lake trout in Blue Mesa and Granby were liberalized in 1996, the changes may have come too late.…”

Section: Discussionmentioning

confidence: 99%

Trophic Economics of Lake Trout Management in Reservoirs of Differing Productivity

Johnson

Martinez

2000

North American Journal of Fisheries Management

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Because of their potential to reach large size, lake trout Salvelinus namaycush are managed as trophy fish in many reservoirs in the western United States. In Colorado, restrictive harvest regulations for lake trout were enacted in reservoirs exhibiting a range of productivities. Annual stockings of kokanee (lacustrine sockeye salmon Oncorhynchus nerka) and rainbow trout O. mykiss sustained sport fisheries, but stocked fish also dominated the prey fish assemblages in these systems. Hydroacoustic surveys suggested that lake trout management allowed an imbalance to develop between prey fish biomass and the biomass of piscivorous lake trout. Piscivorous fish biomass was, on average, 60% of total pelagic fish biomass. Bioenergetics modeling confirmed the imbalance: annual lake trout consumption was near or exceeded annual pelagic prey fish supply (standing stock plus production); the degree of imbalance was greater in less productive reservoirs. Annual subsidies to the food web, in the form of stocked sport fish, were necessary to allow the imbalance between predator and prey populations to persist, especially in the least-productive systems. Though highly sensitive to the size at which hatchery fish are consumed, the per capita costs to sustain lake trout growth at observed levels would total about US$200 per lake trout in the more productive reservoirs and $300-600 per lake trout in the less productive reservoirs. The cost of maintaining high lake trout biomass in these stocked systems may be a difficult management strategy to justify and sustain, either economically or socially.

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“…In many North Fork and Middle Fork tributaries, adfluvial (adult) DV and WCT redd counts have decreased despite adequate habitat quality. Large increases in lake trout numbers and predation in Flathead Lake and the main stem Flathead River have contributed to recent declines in adfluvial DV and WCT abundance (Carty et al 1997, Deleray 1997. This limiting factor conflicts with habitat and passage improvement projects targeting adfluvial trout that mature in Flathead Lake.…”

Section: Project Screening and Prioritizationmentioning

confidence: 99%

Hungry Horse Dam fisheries mitigation : Fish passage and habitat improvement in the upper Flathead River basin

Deleray¹,

Knotek²,

Marotz³

1997

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Hungry Horse Dam Fisheries Mitigation; Kokanee Stocking and Monitoring in Flathead Lake, 1996 Progress Report.

Cited by 3 publications

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Changes in Lake Trout Growth Associated withMysis relictaEstablishment: A Retrospective Analysis Using Otoliths

Changes in Lake Trout Growth Associated withMysis relictaEstablishment: A Retrospective Analysis Using Otoliths

Trophic Economics of Lake Trout Management in Reservoirs of Differing Productivity

Hungry Horse Dam fisheries mitigation : Fish passage and habitat improvement in the upper Flathead River basin

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