Management of Small Impoundments

1
Management of Small Impoundments

• Chapters 21 (22)

2
Introduction

• Pond small impoundment
• lt0.4 ha 40 ha
• 0.2 ha 2.4 ha (AFS Central States Pond
  Management Work Group)
• Dam constructed to impound water
• Various water sources
• Springs, streams, precipitation, runoff

3
Introduction

• Usually privately owned
• Farm ponds
• Livestock water
• Irrigation
• Most numerous in central and southeast
• Important contribution to sportfishing
• Rarely regulated as a water of the US

4
Management Philosophy

• Sustained or improved fishing quality
• High catch rates and above-average sizes

5
Multiple Uses of Ponds

• Boating
• Fishing
• Livestock
• Bird hunting
• Swimming
• Aesthetics

6
Ecological Principles

• Trophic Relationships
• Productivity and Biomass

7
Ecological Principles

• Carrying capacity max mass or density supported
  over a certain time period
• K Density Fish Size

8
Ecological Principles

• Average Fish Size varies as a function of overall
  pond productivity and population density

9
Ecological Principles

• Influence of Aquatic Vegetation
• Increased primary productivity
• Decreased predator foraging efficiency
• Decreased harvest efficiency
• Dense prey populations
• Stunted predator populations

10
Pond Types and Management Options

• Warmwater
• Bass and bluegill, sometimes catfish
• Fall, winter, spring trout (summer kills)
• Most Common and Most research
• Coldwater
• Trout, usually stocked
• Coolwater
• Rare Walleye, hybrid striped bass, perch, etc.

11
All-Purpose Option

• Harvest of LMB, BG, and CC
• 30-38 cm (12-15 in) slot limit for LMB after 4
  years
• Reduces mid-size BG and allow some BG to reach 8
  in
• Harvest 75 LMB per ha (8-12 in)
• Harvest BG and CC at will
• Importance of LMB slot limit
• Over harvest Over population of BG
• Release slot fish and smaller Over population
  and stunting of LBM

12
Harvest Quota Option

• Due to problems with length limits
• Set harvest independent of length
• Quota on number or weight per time
• Difficult
• Need accurate record keeping
• Tend to overharvest larger LMB and underharvest
  small LMB
• Harvest BG and CC at will
• Harvest 3-10 times the amount of LMB
• C/R after quota is reached

13
Panfish Option

• Big panfish instead of LMB
• 15 in min length for LMB
• Abundance of 8-15 in LMB reduce BG density
• Large BG survive and grow gt 8 in
• Small LMB generally
• May compete with BG (remove some)
• Easy unmanaged ponds tend to move in this
  direction

14
Big BASS Option

• Reduce number of LMB 8-15 inches so remaining
  individuals grow large
• Harvest 75 LMB 8-12 in and 13 LMB 12-15 in per ha
  per year
• Release all LMB gt 15 inches (except bucket
  mouths)
• Stock gizzard shad as prey for large LMB
• Catch rate is low but sizes are large
• Larger ponds
• Numerous small BG may reduce recruitment of LMB

15
Catfish Only Option

• In muddy or small ponds
• No structure for spawning or they overpopulate
  and stunt
• Fathead minnow prey
• Unrestricted harvest
• Restocking to replace harvested fish

16
Black Bass Only Option

• Shallow, weedy ponds with too much cover (BG
  stunting)
• Feed on crayfish, bugs, own young
• Need several year classes stocked
• Prevents development of dominant year class
• Inefficient use of pond resources?

17
Trout Options

• Coldwater pondsspring fed
• Usually rainbow trout
• Easy to control by stocking rates (wont
  reproduce in standing waterbrook trout will)
• Must Restock
• Become accustomed to formulated fish foods
• Fee-fishing ponds

18
All Purpose Recipe

• Initial Pond Survey
• Population Status
• Electrofishing and seining
• Assess population balance
• Alkalinity
• Aquatic Weeds

19
All Purpose Recipe

• Kill the Pond
• Initial Stocking
• Forage species (bluegill, shell crackers, fat
  head minnows)
• Predator species (largemouth bass)
• Stocking Rates
• Supplemental Stocking
• Essential in large ponds (gt2 acres)
• Threadfin shad, golden shiners)

20
All Purpose Recipe

• Liming
• Essential if pH lt 7 and Alkalinity lt 20 ppm
• Agricultural limestone
• Why useful?

21
All Purpose Recipe

• Fertilization
• Can triple productivity
• Can cause unwanted algal blooms
• Once started, difficult to stop
• Granular, water soluble, liquid

22
All Purpose Recipe

• Supplemental Feeding
• Dramatically increase size and growth of BG and
  LMB.
• Only recommended if Trophy Bass is the management
  objective.
• Same negatives as fertilizer.

23
All Purpose Recipe

• Aquatic Vegetation Control
• Optimum level at 20 in TX reservoir
• Optimum level at 36 in IL pond

24
Aquatic Vegetation

• Natural Succession of lentic systems
• Depressions accumulate material
• Increased organic matter and nutrients
• Cultural Eutrophication
• Ponds become increasingly susceptible to nuisance
  algae and vegetation

25
Aquatic Vegetation Control

• Mechanical
• Harvesting and Dredging
• Shading
• Draw Down

26
Aquatic Vegetation Control

• Chemical Herbicides
• Copper sulfate
• Nutrients stay
• Depletes DO
• Effective, quick, cheap in small impoundments

27
Aquatic Vegetation Control

• Biological
• Grass carp
• Non-native, illegal in some states
• Escape hatcheries and reproduce
• Triploid variety infertile
• Can completely eliminate vegetation, eat
  invertebrates (crayfish)
• Nutrients stay (convert macrophytes to
  phytoplankton)
• Barley Straw
• May inhibit additional algal growth
• Mechanism uncertain fungal chemicals?
• Nutrients stay

28
All Purpose Recipe

• Aerators and Destratifiers
• Often necessary in fertilized ponds or ponds that
  receive high nutrient runoff.
• Avoid stratification and extremely low oxygen
  levels.
• Expensive (especially with increasing gas prices)

29
All Purpose Recipe

• Harvest Control
• Limit over harvest
• Maintain population balance
• Minimum length limits
• Low recruitment situations
• Protects individuals until they reach maturity
• Slot Limits
• High recruitment where minimum length limits will
  lead to overpopulation and stunting
• Grows bigger fish
• Must harvest small fish

30
Balance and Population Analysis

• Are stocked ponds really in balance?
• Likelihood declines with ponds that are simple
  are artificial
• Artificial ecosystems? Must manage hard to get
  what you want
• Big aquarium?
• Ponds with a natural assemblage within a natural
  habitat are more likely to be a self-sustainable
  ecosystem
• Diversity of habitat
• Sustained source of water
• Prey diversity

31
Balanced Fish Populations

• Characteristics
• Continual reproduction of predator and prey
• Diversity of prey for all predators
• High growth rates
• Harvestable fish in proportion to pond fertility

32
Balanced Fish Populations

• Indices to assess balance
• Biomass Indices
• Length-Frequencies Indices
• Abundance-Weight Indices

33
Biomass Indices FC Ratio

• Total weight of all forage fishes (F) / total
  weight of all carnivorous fishes (C)
• 3-6 good
• 1.4-10 balanced
• Low too many carnivores
• High too many forage fishes

34
Biomass Indices YC ratio

• Total weight of forage fishes small enough to be
  consumed by the average sized carnivore / Total
  weight of all carnivorous fishes (C)
• 1-3 good
• 0.02-5 balanced
• Low too many carnivores
• High too many forage fishes

35
Biomass Indices AT value

• Total availability value
• that is harvestable
• Total weight of harvestable fish / total weight
  of all fish
• Need to define minimum weight harvestable
• 60-85 good
• Low stunted
• High too many big carnivores

36
Length-Frequency Indices Proportional stock
Density (PSD)

• fish of a given species greater than or equal
  to quality length / fish greater than or equal
  to stock length X 100
• Quality Length size most anglers like to catch
• Stock Length size at which fish reach sexual
  maturity, minimum recreational length
• 40-70 balance for LMB
• 20-60 balance for BG
• of fish attractive to anglers

37
Length-Frequency Indices Relative stock Density
(RSD)

• fish of a given species greater than or equal
  to length you want / fish greater than or equal
  to stock length X 100
• Must ID the size you want
• Special case of PSD
• More sensitive to recognizing quality of the stock

38
Comparing PSD and RSD

• Pop 1
• PSD 50
• RSD-38 0
• PSD quality size/stock size
• RSE other size/stock size

• Pop 2
• PSD 50
• RSD-38 15

39
PSD and RSD Size Categories

• Base on percentage of world record lengths
• Stock Length 20-26 of the world record length
  for the species (LMB 20 cm)
• Quality Length 36-41 (LMB 30 cm)
• Preferred Length (LMB 38 cm)
• Memorable Length (LMB 51 cm)
• Trophy Size 80 (LMB 63 cm)
• Table 21.1

40
Abundance and Weight Indices

• Relative Weight (Wr)
• Measured weight (Wt) / predicted or standard
  weight (Ws)

41
Length-Weight Relation

• W aLb
• Exponential relationship
• W is a function of L to some power
• a (constant) and b are parameters from L vs W
  relation
• log W log a b log L
• Equation for a line!
• Ws standard weight

LMB Length-Weight relation
42
W a L b

• b 3
• Isometric growth
• Growing in all directions in proportion
• Shape is not changing (rare)
• b ? 3
• Allometric growth
• Growing faster in girth than length or vise
  versa changing shape
• More common growth
• Old fish grow more in girth than length

43
Wr Wt / Ws

• Do fish weight what they should
• lt 85 underweight and too abundant
• 100 in balance with food supply
• gt 105 too plump pond can support more fish

44
Standard Weight Equations

• Largemouth Bass
• Log10 Ws -5.528 3.273 Log10 L
• Bluegill
• Log10 Ws -5.374 3.316 Log10 L
• Channel Catfish
• Log10 Ws -5.800 3.294 Log10 L

45
Internet Resources

• State Fish and Wildlife Agencies
• http//www.tpwd.state.tx.us/fish/infish/ponds/
  (TX)
• http//www.dgif.state.va.us/fishing/Pond_Managemen
  t/index.html (VA)
• Cooperative Extension Services
• http//www.wvdnr.gov/Fishing/FarmPondMgmt.shtm
  (WV)
• http//msucares.com/wildfish/fisheries/farmpond/ma
  nagement/ (MS)
• http//www.aces.edu/pubs/docs/A/ANR-0577/ (AL)
• http//www.dnr.cornell.edu/ext/fish/pond1.htm (NY)