Grace Gardner, Joe Buchanan,Casey Kristofferson

Pond Zooplankton Analysis at OX Ranch

Outline

• Background• Methods• Data• Results• Management • Summary

Background

• Purpose of ponds• Macrophytes• Location- middle pond• Zooplankton Assessment• October 7th and 8th

Methods

• Onshore vs. Offshore • Equipment• Sampling • Lab Analysis • Reasoning

X

X

X

X

X

X

Black X: Offshore sitesGray X: Onshore sites

Volume of offshore= 14015 m^3Volume of onshore =1300 m^3

Onshore vs. Offshore

vesr.ucnrs.org

wildco.com

Sampling

Reasoning: Daphnia

• Pond Community • Role of Daphnia

Trophic Level 4 Human

Trophic Level 3 Planktivore

Trophic Level 2 Zooplankton Daphnia

Trophic Level 1 Phytoplankton

Data and Results

• Comparisons of Offshore and Onshore zones– Abundances of all Zooplankton genera present– Average length of zooplankton – Average length of Daphnia specifically– Average biomass of Daphnia – If time permits: abundances between night and

day within the offshore zone

Daphnia Ceriodaphnia Alona Cyclopoid Chaoborus Odonata0

0.2

0.4

0.6

0.8

1

1.2

Zooplankton Abundance; Onshore vs Offshore

Onshore Offshore

Genera

Abun

dace

#/L

10

0.5

1

1.5

2

2.5

3

Length of Zooplankton; Offshore vs. Onshore

OffshoreOnshore

Pond Zone

Aver

age

Lent

h (m

m)

11

1.05

1.1

1.15

1.2

1.25

1.3

Daphnia Length: Offshore vs. Onshore

Offshore Onshore

Pond Zone

Leng

th (m

m)

10

1

2

3

4

5

6

7

8

9

Daphnia Biomass (mg/L) of Onshore vs. Offshore

OffshoreOnshore

Pond Zone

Biom

ass (

mg/

L)

Large-bodied Daphnia benefits

• Burns et al. 1968, found a correlation between length of zooplankton and diameter of particle able to filter

• This means that the larger-bodied zooplankton within onshore zone are providing top-down control upon algal blooms

• Management implications with removal of these zooplankton

(Burns 1968)

(Burns 1968)

Parameters Pond Total

Daphnia Biomass (mg/L) 11.77776678

Daphnia Abundance (#/L) 1.405452

Daphnia Average Length (mm) 1.193735

Zooplankton Length (mm) 1.86216

Daphnia length range: 0.30928- 2.7062mm

Management

• Ox Ranch Plan• Suggestions• Role of management plan

Pond Status

• Pond is in great condition for Daphnia.• High densities of Macrophytes

• Good for daphnia• Bad for fish

Management Suggestion

• Macrophyte removal• Dredging• Fish habitat• Fish stocking• Shading• Role

Macrophyte Removal

• Remove 30-40% of macrophytes• Mostly near/around dock• Significance

Dredging

• 3 meters deep• In front of dock• Depth for fish habitat

Fish habitat

• Brush piles in open water• In dredging area• Christmas trees, brush, anything.• (Bassett et al. 1994)

Stocking

• Conservative • Fish population boom at beginning• Ecosystem reaction

Shading

• Plant willows• Shading of pond• Bank stabilization

Role of Management plan

• Economically effective• Maintain balance• Supply fishing opportunities

Summary

• Background• Methods• Data• Results• Management• Questions?

Citations• Bassett, C. E. 1994. Use and evaluation of fish habitat structures in lakes of the eastern United States by the USDA Forest

Service. Bulletin of Marine Science, 55: 1137-1148. http://idahoid.library.ingentaconnect.com/content/umrsmas/bullmar/1994/00000055/F0020002/art00070

• Burks, R.L., Jeppersen, E., and Lodge, D.M. 2001. Littoral zone structure as Daphnia refugia against fish predators. Limnology and Oceanography 46: 230-237.

• Burns, C.W. 1968. The relationship between body size of filter-feeding cladocera and the maximum size of particle ingested. Limnology and Oceanography 13: 675-678.

• Wetzel, R.G. 2001. Limnology. 3rd Ed. Academic Press, San Diego, CA, U.S.A.

Daphnia Ceriodaphnia Alona Cyclopoids Chaoborus Odantata0

0.5

1

1.5

2

2.5

Zooplankton Abundance; Night vs. Day Offshore

NightDay

Species

Abun

danc

e (#

/L)