NonNative Fishes of Coeur d'Alene Lake

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Non-Native Fishes of Coeur d'Alene Lake

• CDA Tribe

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Fish Species of Coeur dAlene Lake

• Longnose sucker Catostomus catostomus
• Bridgelip sucker Catostomus columbianus
• Largescale sucker Catostomus macrocheilus
• Sculpin Cottus sp.
• Westslope cutthroat trout Oncorhynchus clarki
  lewisi
• Mountain whitefish Prosopium williamsoni
• Northern pikeminnow Ptychocheilus oregonensis
• Longnose dace Rhinichthys cataractae
• Speckled dace Rhinichthys osculus
• Redside shiner Richardsonius balteatus
• Bull trout Salvelinus confluentus
• Northern pike Esox lucius
• Black bullhead Ictalurus melas
• Brown bullhead Ictalurus nebulosus
• Channel catfish Ictalurus punctata
• Pumpkinseed Lepomis gibbosus
• Smallmouth bass Micropterus dolomieui
• Largemouth bass Micropterus salmoides
• Rainbow trout Oncorhynchus mykiss

Of the 25 species of fish found Coeur dAlene
Lake only 11 are native
Wolf lodge bay early 1900s
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• The long term vision of the Tribe is to manage
  the lake for sport and subsistence fisheries
  directed primarily at native fishes like
  westslope cutthroat trout and mountain whitefish.
• The Tribe feels confident that this can be done
  in the presence of the multitude of non-native
  species occupying Coeur dAlene Lake.
• The species of most concern are Northern Pike and
  Smallmouth Bass.

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Restoration is Essential but Regulation is Key

• What does this mean?
• It means that the Tribe focuses its efforts on
  restoration of tributaries where populations of
  native species currently exist.
• This also means that little or no money is left
  to manage the fish populations in the lake.
• So, where does that leave us?
• It leaves us with one option and that is to use
  our regulatory authority to manage the
  populations in the lake.

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Todays Situation

• Very few studies have been completed that give us
  clues to the interaction between native and
  non-native populations in the lake.
• Ones that are completed point towards negative
  interactions between young natives species and
  several non-natives species including smallmouth
  bass and northern pike.

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Smallmouth bass were illegally introduced into
Coeur dAlene Lake sometime in the early 1990s
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How Did We Get Here?

• Most non-native species in Coeur dAlene Lake
  were introduced in the late 1800s and early
  1900s with kokanee being introduced in 1937.
• With the advent of cheap portable aeration
  devices in the 1970s non-native species have
  been illegally introduced into almost every lake
  in North Idaho including Coeur dAlene Lake.
• Most notably Northern Pike

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10 pound northern pike are very common in Coeur
dAlene Lake
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What do we do now?

• Various strategies were considered for the
  management of non-native species.
• Those strategies included do nothing, removal
  (trap nets, electrofishing, gill nets, and purse
  seines) and harvest regulations.
• The current option being used is harvest
  regulation.

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Where do we go from here?

• We examine the effectiveness of current harvest
  regulations versus survival of cutthroat trout in
  the lake.
• If lake survival of cutthroat is at acceptable
  levels then we will most likely do nothing more
  than that.
• If survival is exceptionally low then more
  drastic action will be taken.

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Conclusions

• Non-native species are here to stay.
• Non-native species present some threat to native
  species in Coeur dAlene Lake.
• Results of studies are inconclusive as to how
  much of a threat they are.
• Current management is to regulate non-native
  species by increasing harvest with liberal bag
  limits (or no bag limits at all) and year long
  seasons.
• We will wait to see if more drastic actions are
  needed to protect native species in Coeur dAlene
  Lake

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