SMB KnowThyEnemy

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Nonnative Fish Control Workshop Grand Junction, CO December 12, 2006 Smallmouth Bass Life History: Know Thy Enemy Patrick J. Martinez Colorado Div. of Wildlife Grand Junction

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Habitat: Water, substrate & thermal conditions Biological: Age & growth, diet, reproduction Ecological: Interactions with other biota UCRB: Distribution in rivers & reservoirs; invasiveness Control: Mechanical, habitat, chemical, policies? Smallmouth Bass Micropterus dolomieu

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Smallmouth Bass - Habitat

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Smallmouth Bass - BIOLOGICAL

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Age & Growth: SMB Age & Growth and Body Condition Colorado River in Grand Valley & Middle Yampa River

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Some SMB cannibalism SMB prey on native fishes Smallmouth Bass - Ecological SMB prey energy content (cal./kg): insects@400, fish@600 & crayfish@800; crayfish absent in YAR in 1977, now abundant

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Colorado Yampa

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Small-bodied Fish (SBF) Equivalents Estimated SBF biomass+annual production = 160 kg/km

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Smallmouth Bass - UCRB

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SMB Origins & Invasiveness in UCRB: Blue Mesa? Bottle Hollow Rifle Gap Flaming Gorge Starvation Lake Powell McPhee Harvey Gap Rio Blanco Elkhead Juniata

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Time late 1800’s & 1970’s & 1990’s & establ. early 1900’s 1980’s 2000’s COR abundant rare common GUR none rare none WHR common rare rare YAR abundant abundant abundant In CO

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- Key issue in native fish protection scenario becomes how feasible would it be to encourage angler harvest as supplemental means of SMB reduction & control in YAR - SMB maintain widespread abundance, high densities in some reaches, and have recently expanded their range into DNM Despite reported & purported angler enthusiasm for & utilization of SMB fishery in Yampa River: - SMB retain high PSD despite demographics suggesting only moderately productive population characteristics - SMB display high Wr, which is more attributable to crayfish availability than to removal by angler harvest

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The Use of Water Temperature, Discharge & Turbidity to Approximate the Duration of Optimal Conditions for Smallmouth Bass Angling in the Yampa River

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RBT: decline in foraging strikes & feeding behavior at higher turbidity, also prey within visual field often ignored SMB: increased turbidity reduced reaction to prey, but not foraging success upon reacting to prey

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Suspended sediment transport: - YAR above LSR near Maybell, 1998-2002 QS = 0.0000581 Q2.13, where QS = sediment discharge in tons per day; Q = water discharge in cfs - Elliot, J. G. & S. P. Anders. 2005. Summary of sediment data from the YAR & Upper GRR Basins, CO & UT, 1993-2003. Suspended sediment concentration (SSC): QS = QW * SSC * 0.0027, where QS = sediment discharge in tons per day; QW = water discharge in cfs; SSC = suspended sediment concentration in mg/l - Dinehart, R. L. ????. Sediment transport at gaging stations near Mt. St. Helens, WA, 1980-1990. Data collection & analysis. USGS. http://vulcan.wr.usgs.gov/Projects/Sediment_Trans/PP1573/PDF/pg1-30.pdf

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Convert SSC to NTU (Nephlometric Turbidity Units): - SCCmg/l = 3.399 NTU – 5.603 - Barrett, J. C., et al. 1992. Turbidity-induced changes in reactive distance of rainbow trout. TAFS 121:437-443. Rainbow trout reactive distance vs. turbidity (NTU): - RDcm = -1.09 NTU + 52.81, where RD = reactive distance in cm - Barrett, J. C., et al. 1992. Turbidity-induced changes in reactive distance of rainbow trout. TAFS 121:437-443. Smallmouth bass RD vs. NTU: - RDcm = 65.0 * 2.718(-0.05 NTU) - Sweka, J. A. & K. J. Hartman. 2003. Reduction of reactive distance & foraging success in smallmouth bass exposed to elevated turbidity levels. Environ. Bio. of Fishes 121:437-443.

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http://www.deq.state.or.us/WQ/WQRules/Rulemaking/Div041DraftTechBasisRevTurbidity.pdf

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1996-2005 Discharge 1998 “High” flow 2004 “Low” flow

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1998-2005 Temperature 1998 2004

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Jun 15- Sept 30= 16 weeks 1998 Temperature

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Aug 7- Sept 30= 8 weeks 1998 Discharge Access by boat = 5 weeks

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Jun 1- Sept 30= 18 weeks 2004 Temperature

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Jul 7- Sept 30= 12 weeks 2004 Discharge Access by boat = 5 weeks

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Yampa River smallmouth bass sport fishery - SMB fishability 6-10 weeks due to turbidity & access - further restricted by base flow storm induced turbidity - angler use characterized as low, fish “unpressured” - <200 cfs limits boat access for anglers to only 5 weeks - private land restricts public access in some reaches - shore access limited due to road conditions (storms) - angling unable to control SMB due to local conditions - unpredictable access & turbidity limits organized derby - restricted to 8-12 optimum weeks in Jul, Aug & Sep

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June 2005 August 2005

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Smallmouth Bass - Control