B.W. Ho, A. R. Pape , C. Stice , N.S. Penoncello , L. Gauthier

B.W. Ho, A. R. Pape, C. Stice, N.S. Penoncello, L. Gauthier

Zooplankton Community Assessment in Baron Pond

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Introduction• Location • Magee Rd. (5.6 miles N.E. of Gennesse ID.) • Interest in management and fishery

Objectives• Determine the biotic community of Baron Pond.

– Determine zooplankton and macro-invertebrate species abundance and distribution

– Assess whether zooplankton and macro-invertebrate community is sufficient to support a fishery within the pond

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Hypotheses• 1: Zooplankton and macro-invertebrate species vary in

abundance between the littoral and pelagic areas of the pond.– Ho: There is no difference between littoral and pelagic

abundances.• 2: The zooplankton and macro-invertebrate community is

sufficient to support a fishery within the pond.– Ho: The community will not be sufficient to support a fishery

within the pond.

Methods1. Sampled 2 pelagic sites with Wisconsin-style

zooplankton tow net (12.5 cm, 80 µm)2. Sampled 2 littoral sites with D-net (251.6 cm2, 500 µm).3. Samples preserved with formalin (10%)4. Counted zooplankton using dissecting microscopes 5. Analyzed data using Microsoft Excel

Methods: 1

• Two sampling sites– Pelagic zone 1: 1.9 m (6.5 Liters)– Pelagic zone 2: 3.0 m (19.6 Liters)

• Obtained triplicate samples• Sampling limitations

– Tow length = site depth-net length– Not representative of entire water column– Bias toward surface

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Study Site

Pelagic zone 2 (1.9m)

Pelagic zone 1 (3 m)

Methods: 2

• Two littoral sampling sites– 1.5 m from shore – Volume sampled 26,312

L/site• Obtained triplicate samples• Sampling limitations

– Shape of net difficult to calculate area of sample

--Accuracy www.dynamicaqua.com

Study SiteLittoral zone 2

Littoral zone 1

Pelagic zone 2

Pelagic zone 1

Methods: 3

• Pelagic samples condensed using 80 µm mesh

• Littoral samples condensed using 500 µm• Samples were preserved in formalin until

analysis

Methods: 4

• Samples washed of formalin • Complete pelagic tow counts

– Direct enumeration /back calculation• Littoral zone samples counted

– Subdivided/ back calculated

Results: Littoral

Ephem

eropte

ra

Chiron

omida

e

Oligoc

haeta

Odona

ta

Ostrac

od

Cyclop

oids

Chaob

orus

Corixid

ae

Gastro

poda

Nemato

da0

0.02

0.04

0.06

0.08

0.1

0.12

Littoral Zone Site 1Littoral Zone Site 2

Taxon

Mea

n O

rgan

ism

s/L

Results: Pelagic

Chironomidae Daphnia Ceriodaphnia Ostracod Cyclopoids Calanoids Harpacticoid Nauplii0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

Pelagic Site 1: Depth (1.9m)Pelagic Site 2: Depth (3.0m)

Taxon

Mea

n O

rgan

ism

s /L

Results• Statistical analysis compared abundances in

littoral vs. pelagic sites• Significantly more Calanoids in pelagic

(p-value=.01)• More Chironomids in littoral sample

(p-value=.03)• Previous research indicates zooplankton vital to

supporting fisheries :– Daphnia– Bosmina

Future Research

• Refine sampling methods– Time of year influences estimates– Many invertebrates entering

quiescence/diapause by November• Sample size

– Schindler trap may reduce bias of pelagic sampling

– Seine net may be better for sampling littoral zone

Acknowledgements

• Frank M. Wilhelm, Tara Johnson (U of I)• Mike and Beverly Baron (Landowners)

www. missouristate.edu