don ingle pond profile 2007 limnology 415 zooplankton & littoral macroinvertebrates brent beller...
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Don Ingle Pond Profile 2007Limnology 415
Zooplankton & Littoral Macroinvertebrates
Brent BellerHeather GangKaren JohnsonRandy Johnson
Outline
Introduction: Heather Methods: Brent Results: Karen Interpretation: Randy
Objectives
To determine fish sources of food present in pond Zooplankton
Identify zooplankton species present Determine densities of zooplankton at different depths and
locations Macroinvertebrates
Identify species present Compare population densities between East and West sides
of the pond. Fish
Analyze stomach contents to determine fish diet
Background Mr. Don Ingle’s pond, located south of Kendrick,
was built in 1995 and filled in 1996 Originally 14-16 feet (~4m) deep, currently
approximately 8 feet deep (2.5m) Deepest point near dam on Eastern side
Original area estimated at 2-3 acres Western third area of pond is shallower to attract
waterfowl
Background Continued… Original Fish Stocking
1500 Trout (500 in three class sizes) 50 breeding Bluegill 50 Largemouth Bass
Excellent trout fishing for next 4-5 years Successive Fish Stocking
500 more Trout 50 Smallmouth Bass 250 Catfish 250 Bullfrog tadpoles
Current Status Cattails have invaded
~100 dump truck loads have been removed to deepen the shoreline and remove cattails
Fishing has declined Bluegills have white worms
Methods
Yellow = Zooplankton
Red = Macroinvertebrate
Methods Macroinvertebrate
Samples Used D-net Two locations
Midway between East end and dock
Far West end Three 1.0 m passes Depth of approximately
0.3 m at each location Just above substrate
Methods
Macrovertebrate Identification Used Dissecting microscope Either counted entire sample or split sample into ¼ and
estimated total
Methods
Fish Samples Used stick seine net Three areas
East of dock At dock West of dock
Methods
Zooplankton Samples Used Schindler Trap Two locations
East End (Deep) 0.5, 1.5, 2.5 m
West End (Shallow) 0.5 m
Methods Zooplankton Identification/Counting
Added sample to dilution (50-85 ml) 2 ml sample from dilution added to counting plate Rotifers
Counted 2 squares Average #/square then multiply by 59 (# squares/plate)
Counted entire plate for other zooplankton Density (#/L) calculated using equations from previous
lab
Macroinvertebrate Results
Total Macroinvertebrate Taxa
0
100
200
300
400
500
600
700
800
900
Baetid
ae
Caenid
ae
Chiron
omida
e
Cerato
pogo
nidae
Chaob
orus
sp.
Nemato
da
Oligoc
haet
a
Ostroc
oda
Mea
n #
of
org
anis
ms
East
West
Macroinvertebrate Results There were more macroinvertebrates in the West than the East Oligochaeta were the dominant taxa with 846 counted Ostrocoda was second with 440 counted Little, if any, Baetidae, Caenidae, and Chaoborus sp. were found High variance between replicates
Fish Sampling Results
Fish sampling Only Young of the Year bluegill were found No fish were caught which were large enough to analyze
stomach contents
Zooplankton Results
Overview West 0.5 m had the highest mean zooplankton
density while East 2.5 m had the lowest Rotifers were the most numerous zooplankton Other zooplankton found included: Cyclopoids,
Ceriodaphnia, and Daphnia
Zooplankton Results
Mean Zooplankton Density
0
20
40
60
80
100
120
West 0.5m East 0.5m East 1.5m East 2.5m
Me
an
De
ns
ity
Zooplankton Results
There was approximately the same density of cyclopoids in all the East sites with East 2.5m having the lowest density
Daphnia and Ceriodaphnia had very low densities
Zooplankton Density (excluding Rotifers)
0
10
20
30
40
50
60
West 0.5m East 0.5m East 1.5m East 2.5m
Zo
op
lan
kto
n D
ensi
ty (
#/L
)
Cyclopoids
Daphnia
Ceriodaphnia
Zooplankton Results
Rotifers were found in the highest concentration at the deepest location (East 2.5m)
Rotifer Density
0
5000
10000
15000
20000
25000
West 0.5m East 0.5m East 1.5m East 2.5m
Ro
tife
r D
en
sit
y (
#/L
)
Interpretation
No adult fish were captured Small seine net Poor footing Inability to access deeper, preferred habitat Other methods possibly more effective
Electroshocking Gillnetting
Interpretation Macroinvetebrate Samples
Possible errors in sampling (dist. above substrate) and identification lead to very high variances
Time constraints Resulted in the inability to generate densities Oligochaeta were the most abundant within the
samples Low species diversity Most were found in the sediment and algae
Interpretation Zooplankton
Rotifers Very high densities observed within pond After dilution were still too numerous to accurately count Inaccurate estimation may have occurred due to uneven
dispersal on the counting plate Daphnia
Low densities observed <10/L
Interpretation High rotifer densities may be explained by a
trophic cascade effect Bluegill prey on daphnia Daphnia prey on rotifers High density of bluegill depresses daphnia,
allowing rotifer densities to increase
Interpretation
No significant differences of mean zooplankton density found between locations or depths at an alpha of 0.05
Questions?