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NON-NATIVE SALMOINDS IN LAKE SUPERIOR. Don Schreiner, MNDNR Steve Schram, WIDNR Shawn Sitar, MIDNR Mike Petzold, OMNR. History. First successful introductions began in late 1800’s with rainbow and brown trout
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NON-NATIVE SALMOINDS IN LAKE SUPERIOR Don Schreiner, MNDNR Steve Schram, WIDNR Shawn Sitar, MIDNR Mike Petzold, OMNR
History • First successful introductions began in late 1800’s with rainbow and brown trout • Coho and chinook salmon first introduced by MI in mid 1960’s, quickly followed by other agencies • Introductions targeted at controlling exotic invaders and redirecting angling effort • All species have become naturalized and are sustained largely by natural reproduction
Fish Community ObjectiveNon-native Salmonids • Manage populations of Pacific salmon, rainbow trout and brown trout that are predominately self-sustaining, but that may be supplemented by stocking that is compatible with restoration and management goals established for native fish species.
Role on Non-native Salmonids in the Lake Superior Fish Community • Species are migratory - spawn in streams and migrate to the lake after smolting • Thermal habitat is limited • Impact on a lake-wide basis is minimal • May have significant impact in tributaries and near-shore areas
Waters of Lake Superior 0-240 ft (0-80 meters) > 240 ft (> 80 meters)
The Fishery • Approximately 1/3 of total angler catch • Expanded sport fishing opportunities • Provided increased shore and stream opportunity • Created a surface water trolling fishery • Contaminant levels less than lake trout
Status – Open Water Creel Surveys • Wisconsin – 1972 – 2000, May 1 – Sept. 30 • Minnesota – 1972 – 2000, Memorial W.E. – Sept. 30 • Michigan – 1987 – 2000, Selected sites May 1 – Sept. 30 • Ontario – Intermittent - selected sites - diaries • Lack of standardization in other recreational fisheries • Spring and fall stream fisheries • Winter fishery
Distribution of Major Salmonids in U.S. Waters of Lake Superior from 1990-2000
Distribution of Major Non-native Salmonids in U.S. Waters of Lake Superior from 1990-2000
Distribution of Major Salmonids in Ontario Waters of Lake Superior 1987-1999
Distribution of Major Non-native Salmonids in Ontario Waters of Lake Superior 1987-1999
Status • Stocking history • Catch history • CPUE in open water recreational fishery
Rainbow Trout • Introduced in 1895 • Present population largely a result of natural reproduction • Return rate of stocked yearlings less than 1% except Kamloops • Increased control of angler exploitation • Abundance has declined since the 1950’s – lake trout, pacific salmon, increased exploitation, stream habitat
Number of Rainbow Trout Caught in U.S. Waters of Lake Superior
Brown Trout • Introduced in late 1890’s • Have naturalized in a number of tributaries • WI and MI still stock in localized areas • Hatchery contribution 50% in WI and 40% in MI • Brule River supports largest naturalized run
Number of Brown Trout Caught in U.S. Waters of Lake Superior
Coho Salmon • Introduced by MI in 1966, MN from 1969-1974 • Quickly became naturalized, no longer stocked • Life cycle of 3 years, anglers mostly exploit age 2+ • Harvest fluctuates greatly – fishing mostly one YC • Slower growth and smaller size than other Great Lakes
Number of Coho Salmon Caught in U.S. Waters of Lake Superior
Chinook Salmon • Introduced by MI in 1967, followed by other agencies • Use larger rivers for spawning • BKD relatively low compared to other Great Lakes • Approximately 75% of chinook salmon are produced by natural reproduction – Peck et al 1999 • All agencies continue to stock – effectiveness ?????
Number of Chinook Salmon Caught in U.S. Waters of Lake Superior
Chinook Salmon Study • Contribution of hatchery fish to fishery • Agency specific fin clips 1988-1990 • Returns assessed from 1990-1994 • Wild fish comprised 75% lake-wide • Hatchery contribution greatest MN-WI-MI-ON • Significant movement
Pink Salmon • Accidentally introduced in 1956 • Have become naturalized • Life cycle of 2 years initially, 3 year life cycle common • Harvest fluctuates greatly – one year class • Late fall boat fishery and fall stream fishery
Number of Pink Salmon Caught in U.S. Waters of Lake Superior
Mean Size of Non-native Salmonids in U.S. Waters of Lake Superior
Mean Size of Non-native Salmonids Among States of U.S. Waters of Lake Superior
Recommendations • Meeting FCO’s based on present knowledge • Determine impact on native species in tributaries and near-shore areas • Standardized creel surveys • Critically review present stocking programs • Use of Lake Superior strains • Effectiveness – Cost:Benefit • Realistic expectations • Disease