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 Objective Non-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 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

Distribution of Major Non-native Salmonids in U.S. Waters of Lake Superior from

Distribution of Major Salmonids in Ontario Waters of Lake Superior

Distribution of Major Non-native Salmonids in Ontario Waters of Lake Superior

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 Stocked in Lake Superior

Number of Rainbow Trout Caught in U.S. Waters of Lake Superior

CPUE of Rainbow Trout in 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 Stocked in Lake Superior

Number of Brown Trout Caught in U.S. Waters of Lake Superior

CPUE of Brown Trout in U.S. Waters of Lake Superior

Coho Salmon Introduced by MI in 1966, MN from 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 Stocked in Lake Superior

Number of Coho Salmon Caught in U.S. Waters of Lake Superior

CPUE of Coho Salmon in 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 Stocked in Lake Superior

Number of Chinook Salmon Caught in U.S. Waters of Lake Superior

CPUE of Chinook Salmon in Lake Superior

Chinook Salmon Study Contribution of hatchery fish to fishery Agency specific fin clips Returns assessed from Wild fish comprised 75% lake-wide Hatchery contribution greatest MN-WI-MI-ON Significant movement

Hatchery Contributions of Chinook Salmon

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