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Zooplankton Analysis of Blue Lake October 23 rd , 2010

Zooplankton Analysis of Blue Lake October 23 rd , 2010. Ben Majsterek , Mary Coyle, Jackie Hancock, and Mary Ruskovich. Introduction. Kettle lake formation, heavy macrophytes , and extremely thick sediment along bottom “bottomless lake”

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Zooplankton Analysis of Blue Lake October 23 rd , 2010

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  1. Zooplankton Analysis of Blue Lake October 23rd, 2010 Ben Majsterek, Mary Coyle, Jackie Hancock, and Mary Ruskovich

  2. Introduction • Kettle lake formation, heavy macrophytes, and extremely thick sediment along bottom “bottomless lake” • 100’s of bullhead catfish as well as 60 hatchery rainbow trout stocked ~2 years ago • Used for fishing, boating, swimming, and as aesthetic appeal • Goal: reduce macrophytes and algae, increase zooplankton abundance, properly manage fish stocks, maximize recreational use

  3. Methods • Site selection • Li-Cor meter – aphoticvsphotic • Temperature profile – unstratified • Northeast to Southwest transect • Five locations, 3 replicates, entire water column with a 12.5 cm closing plankton net • Preserved with formalin for 2 weeks and analyzed at the U of I lab to determine zooplankton density and species distribution

  4. Location of SitesBlue Lake Oct. 23rd , 2010 1 2 3 4 5

  5. Site 1 Mean individuals/L for ceriodaphnia, cyclopoid, and diaphanosoma: 6.33, 7.66, and .333 individuals/L

  6. Site 2 Site 2: Mean individuals/L for ceriodaphnia, leptodora, cyclopoid, diaphanosoma, calanoid, harpacticoid: 8.33, 0.66, 9.33, 1.66, 2 and 0.66 individuals/L

  7. Site 3 Mean individuals/L for ceriodaphnia, leptodora, cyclopoid, and bosmina: 10, 0.33, 3.33, and 0.33 individuals/L

  8. Site 4 Mean individuals/L for ceriodaphnia, leptodora, cyclopoid, and bosmina: 7.33, 0.33, 5.33 and 0.33 individuals/L

  9. Site 5 Mean individuals/L for ceriodaphnia, leptodora, cyclopoid, diaphanosoma, and calanoid: 6, 1.66. 2.33, 0.33, and 1 individuals/L

  10. Total individuals/L for sites 1-5. Individuals/L for ceriodaphnia, leptodora, cyclopoid, diaphanosoma, calanoid, harpacticoid, and bosmina are 38, 3, 28, 2.33, 3, 0.67, and 0.67

  11. Zooplankton Ceriodaphnia Cyclopoid copepod Calanoid copepod Bosmina (Jones, B. 2006)

  12. Fish Species • Bullhead Catfish (Ameiurus spp.) • Diet: plants, detritus, small fish, worms and zooplankton • Rainbow Trout • Diet: midges, Diptera, Ephemeroptera, and Nemouridae larvae, fish, large zooplankton • Largemouth Bass • Diet: crustaceans, variety of invertebrates, fish, and odonate nymphs

  13. Discussion • Significant absence of large zooplankton • Fast growth in trout when first stocked • Large bullhead population • Changes (recent rainbow trout addition) may have long term effects • increased eutrophication • Increased dependency on human supplied feed Current management structures and goals cannot be met without change in other aspects

  14. Alternatives • Ecological Improvement (swimming, aesthetic improvement, improved clarity) • Reduction of trout and bullhead stocks • Fishery Improvement • Continual feeding of trout • Cons: may have long term effects – increased eutrophication • Change fishery structure • Movement from trout fishery to bass • Removal of a large portion of bullhead population

  15. Conclusion • Zooplankton stocks are depleted and cannot sustain current fish populations alone • To improve any aspect of the lake, another factor will have to change i.e. continued fish stocks at these numbers and nutrient levels will may result in murky, algae filled water

  16. References • Ahrenstorff, T. D. and M. R. Helmus. 2009. The influence of littoral zone coarse woody habitat on home range size, spatial distribution, and feeding ecology of largemouth bass (Micropterussalmoides). Hydrobiologia 623:223-233. • Cisneros, R., E. Hooker, and L.E. Velasquez. 1991. Natural diet of herbivorous zooplankton in Lake Xolotlan (Managua). Aquatic Ecology. 25: 163-167. • Jones, B. 2006. Limnology. Indiana University. http://classwebs.spea.indiana.edu/joneswi/e455/ • Newell, A. E. 1960. Biological survey of the lakes and ponds in Coos, Grafton and Carroll Counties. New Hampshire Fish Game Surv. Rep. 8a:297. • Harlan, J. R. and E. B. Speaker. 1956. Iowa fish and fishing. 3rd Ed. State of Iowa. 377pp.  • Steiner L.  2002.  Pennsylvania Fishes.  117-123 http://www.fish.state.pa.us/pafish/fishhtms/chap13.htm

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