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Status and Recovery of Upper Columbia White Sturgeon. What We Know - Impacts. pre-development Kettle Falls “Z” Canyon Bonnington Falls. 16 dams. Lower Bonnington (1897) Revelstoke (1984). other industry. Celgar (1960) Teck Cominco (1906) modernizations (1990’s).
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What We Know - Impacts • pre-development • Kettle Falls • “Z” Canyon • Bonnington Falls • 16 dams • Lower Bonnington (1897) • Revelstoke (1984) • other industry • Celgar (1960) • Teck Cominco (1906) • modernizations (1990’s)
What We Know - Distribution • Border to Grand Coulee • ~2000 adults • likely spawning annually • Trail-Castlegar • ~750 adults • spawning annually (Waneta) • Arrow • ~40 adults • occasional spawning (Revelstoke golf course) • Headwaters • anecdotal • small numbers
What We Know - Genetics • preliminary DNA sampling • Kootenay Lake • Arrow Lakes • below Keenleyside Dam • lower Kootenay River • Ft Shepherd Eddy • Lake Roosevelt (TDB) • microsat DNA • Kootenay Lake different • others same • mtDNA • Kootenay Lake different • some substructuring of Columbia • common spawning location?
What We Know – Spawning • highly variable between locations • 10-11°C at Revelstoke, 14-18°C at Waneta • shallow at Revelstoke (<3 m), deep at Waneta (>10 m) • late summer at Revelstoke, mid summer at Waneta • Pend d’Oreille flows at Waneta not impacting spawning behaviour • eggs and subsequent larvae viable
What We Know – Fish Culture • FFSBC operations in place • Kootenay Trout Hatchery • since 2001 • broodstock, spawning, rearing • 12,000+ yearlings annually
What We Know – Juveniles • annual juvenile indexing • 1st year survival hatchery yearlings 60% • subsequent years 90%+ • excellent early growth (~0.06 cm/d, 1.36 gm/d) • Mysis relicta bulk of diet • depositional habitats preferred • juveniles highly concentrated in key areas • share eddy habitats with adults • evidence of recruitment • a few fish each year, especially in Washington • 1997 brood? …a high water year
What We Don’t Know • deformities • fins and head asymmetry • up to 50% of some families • not impacting early survival, but not evident in wild adults • mechanism?
What We Don’t Know • predation impacts • walleye 1965-1975 • larval substrate preferences and habitat suitability • imprinting • survival rates (require refinement) • carrying capacity • role of contaminants • unusually cool summer temps (Revelstoke) and warm winter temps (Coulee to Arrow Lakes) • age first maturity, spawning periodicity • upper limit of distribution • cause of recruitment failure
Critical Habitats? • spawning • Revelstoke golf course • Columbia - Pend Oreille confluence • Northport (USA) • others? • lake head/depositional • larval settlement • juveniles and adults • Arrowhead • Marcus Flats (USA) • why? • spawning occurs…not successful • start of exogenous feeding difficult