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State-of-Lake Superior’s Fishes: Assessing Lake Superior’s Fish Community Objectives

State-of-Lake Superior’s Fishes: Assessing Lake Superior’s Fish Community Objectives. Great Lakes Fishery Commission FCO’s. Lake Trout. Lake Trout - Growth. Lake Trout.

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State-of-Lake Superior’s Fishes: Assessing Lake Superior’s Fish Community Objectives

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  1. State-of-Lake Superior’s Fishes: Assessing Lake Superior’s Fish Community Objectives

  2. Great Lakes Fishery Commission FCO’s

  3. Lake Trout

  4. Lake Trout - Growth

  5. Lake Trout • Objective: Achieve and maintain genetically diverse self-sustaining populations of lake trout that are similar to those found in the lake prior to 1940, with lean lake trout being the dominant form in nearshore waters, siscowet lake trout the dominant form in offshore waters, and humper lake trout a common form in eastern waters and around Isle Royale. • Lake Trout appear to have reached density-dependence; we are closely assessing trends as there are recent indications of potential declines • Stocks are almost entirely self-sustaining

  6. Lake Whitefish

  7. Lake Whitefish • Objective: Maintain self-sustaining populations of lake whitefish within the range of abundance observed during 1990-99. • Harvest, effort and catch-per-unit effort are similar over past two decades

  8. Lake Sturgeon Southern and Eastern Populations Batchawana R Sturgeon R Chippewa R Goulais R Ontonagon R St. Louis R Tahquamenon R Montreal R Bad R White R

  9. Lake Sturgeon • Objective: Rehabilitate and maintain spawning populations of lake sturgeon that are self-sustaining throughout their native range. • Prognosis is improving; general trend of increasing abundance, identification of more spawning populations • Most populations remain below minimum viable population targets

  10. Brook Trout

  11. Brook Trout • Objective: Maintain widely distributed, self-sustaining populations in as many of the historical habitats as is practical. • Progress is slow; limited success in most areas despite intensive stocking • Isle Royale and Nipigon Bay remain bright spots

  12. Walleye • Objective: Maintain, enhance, and rehabilitate self-sustaining populations of walleye and their habitat over their historical range. • All known populations remain extant, but well below historic abundance in most areas • Limited data from LSTC agencies

  13. Pacific salmon, Rainbow Trout, Brown Trout • Objectives: Manage populations of Pacific salmon, rainbow trout, and brown trout that are predominantly self-sustaining but that may be supplemented by stocking that is compatible with restoration and management goals established for indigenous fish species. • Populations are self-sustaining, and stocking has been greatly reduced in most jurisdictions

  14. Prey Species 2009: 1.12 kg/ha - lowest biomass on record: 2012: 1.14 kg/ha 2011: 3.63 kg/ha 1983: 2.15 kg/ha

  15. Prey Species • Objective: A self-sustaining assemblage of prey dominated by indigenous species at population levels capable of supporting desired populations of predators and a managed commercial fishery. • This objective is generally met, but there are concerns about low prey fish biomass, and whether there are enough prey fishes to meet predator demand

  16. Sea Lamprey

  17. Sea Lamprey

  18. Sea Lamprey • Objective: Suppress sea lampreys to population levels that cause only insignificant mortality on adult lake trout. • Mixed indicators, but consensus was that sea lampreys continue to cause significant mortality in every management unit

  19. Nuisance Species • Objective 1: Prevent the introduction of any non-indigenous aquatic species that is not currently established in Lake Superior; Objective 2: Prevent or delay the spread of non-indigenous nuisance species, where feasible; Objective 3: Eliminate or reduce populations of non-indigenous nuisance species, where feasible. • Limited new introductions into Lake Superior • Nuisance species do continue to slowly spread within the basin • Impact of existing nuisance species remain spatially limited

  20. Species Diversity • Objective: Protect and sustain the diverse community of indigenous fish species not specifically mentioned earlier (burbot, minnows, yellow perch, northern pike, and suckers). These species add to the richness of the fish community and should be recognized for their ecological importance and cultural, social, and economic value. • Limited data on which to base this assessment, but no indication in surveys that there are any issues with these native fishes

  21. Habitat • Objective: Achieve no net loss of the productive capacity of habitat supporting Lake Superior fishes. Where feasible, restore habitats that have been degraded and have lost their capacity for fish production . Reduce contaminants so that all fish are safe to eat. Develop comprehensive and detailed inventories of fish habitats. • Nearshore and offshore habitat remains excellent, capable of supporting nearshore and offshore fishes • Some inshore, embayment and tributary habitats remain stressed and are not capable of meeting FCO’s • Contaminant picture is mixed; some legacy contaminants are declining, but others are emerging

  22. Summary • Offshore and nearshore fish community is in good shape • Dominated by self-sustaining, primarily native fishes • Inshore, embayment and tributary fishes face anthropogenic impacts, or a poorly assessed • Identified gaps in our assessments • Limited interest by many LSTC members in these fishes

  23. Key Recommendations • Regularize quinquennial 1) offshore hydroacoustic; and 2) Lake Sturgeon surveys in conjunction with CSMI • Develop and implement routine assessments and standardized reporting for 1 ) Brook Trout; 2) inshore fishes; and 3) key invertebrate prey species (Diporeia, Mysis) • Conduct modelling to assess sustainability of proposed siscowet fishery • Determine relevance of species-specific FCOs under current ecosystem management framework

  24. Acknowledgments • LSTC is able supported by many individuals and agencies

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