SOLitude Lake Management
Woodland Pond Electro-fishing Study
4/11/12
Materials and Methods:
Using a MidWest Lake Electro-Fishing System fish species were
collected and fisheries assessment information was recorded.
Information was gathered over the course of two days. The first
run included collection of all fish. The following two days of work
focused on removing the intermediate size Black Crappie and
Largemouth Bass. Length and weight data was recorded and
logged into a database to be assessed.
Results Overview
Seven (7) species of fish were collected. Largemouth Bass, Black
Crappie, Chain Pickerel, Bluegill, Redear Sunfish, Golden Shiners
and Koi.
Largemouth Bass and Black Crappie make up the majority of the
lakes biomass.
Young of the year Bluegill and Redear Sunfish numbers are “Fair”.
Adult Bluegill numbers are “Low”.
Woodland Pond Fishery Health Indicator
***Scale is geared towards Bass and Bluegill Growth***
Woodland Pond Parameter:
Rating: Notes:
Habitat
Poor
Lacking dense cover required
by smaller fish
Fair
Chemistry was good at time of
sampling
Good
Lake has suitable spawning
substrate
Spawning Locations Good
Lake has suitable spawning
locations
Productivity (food
source)
Water is lacking in
phytoplankton and
zooplankton
Cover
Water Quality
Spawning Substrate
Poor
Fish Population
Predator/Prey Ratio Poor
Predator heavy
Relative Weight of
Predator Fish
Wr of the bass was acceptable
Good
Largemouth Bass
Micropterus salmoides
Habitat and Biology:
Spawning occurs from April to late May, when water temperatures reach
63º to 68ºF and takes place in deeper water than sunfishes, usually1 to 4
feet. Males build the nests which are at least 30 feet apart. After
spawning, the female leaves the nest although she, or another female, may
return to spawn later. The eggs hatch in 3 to 4 days. Females produce
2000 to 7000 eggs per pound of body weight. Until they are 2 inches long,
largemouth juveniles feed on plankton and miscellaneous insects and
other invertebrates. Average life span is from 10 to 12 years and they
typically grow 12 to 30 inches in length although growth rates are
extremely variable depending on the water body. Largemouth have a
tendency to become overpopulated and often require active harvest of
intermediate size fish to prevent size classes from becoming stunted.
Black Crappie
Pomoxis nigromaculatus
Habitat and Biology: Spawning season is April to May when the water
temperatures are higher than 68ºF. Before spawning, black crappie form
schools and venture to feed into shallow water where they can be caught
in large numbers. Nests are constructed in water 10 inches to 2 feet deep.
They are usually built in sandy bottom in weedy areas. Eggs hatch in 3 to
5 days. Young crappies are plankton feeders but older fish feed on insects
and fish. Considerable feeding takes place at night. They can live for
eight years and grow 12 to 18 inches in length. Crappie are a predator
species and tend to become over populated, especially in smaller ponds.
Bluegill (Bream)
Lepomis macrochirus
Habitat and Biology:
Bluegills begin spawning when the water temperature reaches 60°F and they have a
protracted spawning season lasting from April to September. The bluegill nests in
colonies and prefer sites that are firm sand or mud with some debris but little
vegetation. The nests are usually built in water 1 to 3 feet deep. They typically reach
maturity in year 1 or 2. Bluegills are routinely stocked in lakes and ponds as food for
Largemouth Bass. The long spawning season of bluegill give them tremendous
reproductive potential. Bluegills feed during the day and most actively in the
morning and afternoon. They eat a wide variety of organisms including significant
amounts of plant material. Young bluegills feed on plankton while larger
individuals eat insects and other larger particles. They feed throughout the water
column. Bluegills live for 5 to 6 years and grow 6 to 10 inches in length.
Note: Bluegills are density dependent, meaning that as their number increase, their
relative sizes decrease. It is therefore imperative to catch and remove smaller fish to
avoid overpopulation if managing for large Bluegill.
Redear Sunfish
(Shellcracker)
Lepomis microlophus
Habitat and Ecology: Spawning occurs during May, June and July when
water temperatures reach 70⁰F. They prefer water three to four feet deep,
and a firm, shelly bottom, often near a dropoff. Nesting sites are often
near aquatic vegetation. Breeding behavior is similar to other sunfish,
with the males doing the nest building and guarding the young. A
female may lay between 15,000 to 30,000 eggs during a spawn. Redear
sunfish have extensive molar surfaces on the pharyngeal arches and
associated musculature that enables the fish to crack mollusk shells,
hence the local name of shellcracker. They are usually stocked in small
ponds and lakes with bluegills and largemouth bass. They grow quite
well in these environments, and because they feed on mollusks and
benthic aquatic insect larvae, they do not compete with bluegills.
Individuals live for six years and grow 8 to 11 inches in length.
Golden Shiner
Notemigonus crysoleucas
Habitat and Biology: The body of the golden shiner is deeply and
laterally compressed, with a lateral line that curves toward the belly. The
golden shiner is a slow-water fish that thrives in ponds. Spawning occurs
from April to July when water temperatures exceed 68ºF. Females lay
adhesive eggs in shallow water over vegetation, including filamentous
algae and rooted aquatic plants. The eggs are usually broadcast with no
nesting or parental care but some golden shiners have been reported to
spawn over the nests of both bluegills and largemouth bass. Growth is
typically rapid and maturity is usually reached at age 2 although fast
growing fish may spawn during their second summer. Zooplankton
forms a large part of their diet. They are also known to feed on algae,
insects and eggs of other fish species. They grow 2 to 9 inches in length.
Chain Pickerel
Esox niger
Habitat and Biology: Chain Pickerel can withstand temperatures 95ºF and
higher and some salinity. The chain pickerel is normally a spring spawner
and spawning takes place when water temperatures reach 47º to 52ºF.
Spawning continues intermittently for a day or two and the sticky eggs
adhere to vegetation. Hatching takes place in 11 or 12 days where the
young will remain in schools and they begin to feed after about a week.
Sexual maturity is reached at age 4 or 5. Chain pickerel are predaceous,
opportunistic feeders. They feed on fish and crayfish during the night and
day. The live for 8 to 10 years and grow 15 to 30 inches in length. This
efficient predator lies motionless along the margins of aquatic vegetation
or undercut banks. It can also live in deeper parts of lakes that might be
void of vegetation and it can tolerate acidic waters.
Materials and Methods:
Water Quality data was collected using a Hanna 9828 Multimeter
Woodland Pond Water Quality
Parameter:
Reading
(Surface)
Unit
Atmospheric Air
Temperature
56
Fahrenheit 60-82
Water Temperature
62
Fahrenheit 60-75
Dissolved Oxygen
12.48
mg/l
>5
pH
7.43
mg/l
6.8-8.2
Conductivity
59
us/cm
>50
Visibility
>5
Feet
24” (Plankton)
Optimal Range
Fish Removal
Nice Female Largemouth (released)
US Fish and Wildlife transported the fish that were
harvested for Mussel propagation
Species
Number removed
Largemouth Bass
422
Black Crappie
1351
Male Bass
Female Bass
Male Bass are ideal to harvest in comparison to female bass. Female
bass have the potential to get very large, male bass do not.
Determining if a bass is male or female can be done with the naked
eye in the spring based on simple observations. Making a practice
of harvesting these males will help you reduce the number of
mouths to feed and give your bass population a needed edge to
support a population of larger bass.
Fish Removal
Many of the fish removed were used by the
state to propagate Fresh Water Mussels in
Virginia by VA State Biologists. Most
freshwater mussels must use a host fish to
complete their life cycle as their larvae are
parasitic. Some mussels use a small number
of host fish and some mussels use a wide
variety of host fish. When mussel larvae
hatch they must attach themselves to the gills
of fish. Once attached to the gill they will
develop into a juvenile mussel. The
Largemouth Bass collected were used to
propagate six species of mussels here in
Virginia – Yellow Lampmussel, Eastern
Lampmussel, Eastern Pondmussel,
Wavyrayed Lampmussel, Pocketbook, and
Pink Mucket.
The Yellow Lampmussel, Eastern
Pondmussel and Pocketbook are listed as
species of greatest conservation need on the
VA Wildlife Action Plan.
Pink Mucket is endangered and is extirpated
from VA.
Relative Weight Index (Wr)
Wr =
_______(Actual Weight of Captured Fish) * 100_______
Standard Weight of Fish at Same Length (From Table)
•Relative Weight is the ratio of the actual weight of a fish to what healthy
fish of the same length should weigh, called standard weight. Fish with
high relative weights are fat while those with low relative weights are
thin.
Relative Weight Reference:
Wr
Condition of Fishery
<75
Poor
80
Balanced
90
Healthy
100+
Quality
Relative Weight (Wr) Reference
This table helps illustrate the relationships between Wr and
current conditions within a fishery
Largemouth Bass Relative Weight
High
Low
Bluegill Relative Weight
High
Low
•Pond
is Well Managed
•Balanced Predator and Prey
Ratio
•Proper Habitat
•Predator
•Bluegill
•Poor
Crowded
•Competing Forage Species
Crowded
•Competing Predator Species
•Hybrid Bluegill Present
Fertility
•Inconsistent Management
•Competing Species
•Excess Weeds
•Poor “Habitat”
Largemouth Bass Length Distribution
Percent of Population
25
Woodland Pond
Balanced Fishery
20
Quality Fishery
15
10
5
0
8
9
10
11
12
13
14
Size Class (inches)
15
16
17
>18
Chart A
Largemouth Bass Relative Weight (Wr)
Distribution Graph
5
Wr = 100 (Quality)
Wr = 80 (Balanced)
Woodland Pond
Weight (lbs)
4
3
2
1
0
10
11
12
13
14
15
Size Class (inches)
16
17
Chart B
18
Woodland Pond Goals
To create a self-sustaining lake that has good fishing. Fish caught are
healthy and vary in size with a population of quality fish living within the
lake.
This is a obtainable goal, but will require following through with a fisheries
management plan that is tailored to the direct needs of the lake.
A Few Keys to Success
“Habitat” is the most important part of fisheries management. Habitat
includes: water chemistry, productivity of the water, contour of the bottom,
fish cover, vegetation, spawning locations and spawning substrate. Having
proper habitat required by the fish species within the water body is critical
to the balance of the ecosystem. Without the proper habitat fish
populations have difficulty staying balanced and fish growth is often poor.
Maintaining a balanced Predator and Prey Ratio is critical in the process of
growing fish. It takes ten pounds of forage fish to grow one pound of
predator fish. Water bodies that have overpopulated size classes of
predator fish will maintain a stunted predator population until the negative
cycle is broken. This cycle can be broken through predator harvest and
stocking forage fish. Often times restructuring the habitat is also required.
Keep fish harvest and fish stocking records. Successfully manipulating a
fishery occurs over the course of multiple years. Management strategies
require adjustment based on the response of the fishery. Keeping good
records will aid in the process of trouble shooting a management strategies
and improve fish growth rates.
Discussion
The fishery is predator heavy. The Largemouth Bass have 2 size classes that
are overpopulated based on the goal of a balanced fishery (See Chart A)
Largemouth Bass and Black Crappie account for a large portion of the lakes
biomass. A great deal of fish have been removed throughout this study;
1773 fish, averaging ~14 fish per acre. This is a great step towards
correcting the lakes issue, but is only one of several steps that can be taken
to improve the lake. Annually harvesting the intermediate size crappie and
bass is a management technique that should be implemented. Harvesting
15 lbs of predator fish per acre annually would help the lake shift to a more
productive fishery. This harvesting process can be completed using electrofishing equipment on an annual bases if fisherman are unable to remove a
sufficient number when angling. All bass 14 inches and smaller should be
harvested.
Relative Weight data shows that the bass population is currently healthy
(See Chart B). It is important to note that the female bass are getting ready
to spawn. This is inflating the health of the bass population.
The adult Bluegill are very low in population. This is a result of too many
predators, not enough cover and lack of available food.
Discussion
The lake is lacking the proper cover required by the fish species. The lack
of cover for smaller fish is a lead factor in why the lake is predator heavy.
Improving the cover throughout the lake is critical in the process of creating
a more balanced and more productive fishery. Establishing cover in a
couple dozen places throughout the lake would prove to be very beneficial
to the success of the fishery. The cover can be either natural or artificial.
Artificial cover is often used because it is permanent and does not require
revamping every few years. Natural cover is often used because it is
inexpensive. Improving the cover can be done over the course of a few
years, but it is important to start the process. Improving the cover will also
improve the fishing experience. Proper placed fish cover allows fisherman
to target predator fish more easily.
Improving the phytoplankton and zooplankton populations in the lake
would greatly improve the quality of the fishery. Based on the lakes low
Alkalinity level (~10 mg/l) it will be very difficult to get the lake to
respond well to a fertilizing program. To get the lake on a fertilizing
program would require applying 3-4 tons of limestone per acre every few
years. This is not practical based on the current budget and goals. The best
use of resources based on the lakes current needs would be to shift the
predator and prey ratio through harvesting predators and stocking forage
fish while improving the cover required to improve the survival of the
smaller fish.
Discussion
Stocking forage fish is an ideal approach to improving the fishery, but
stocking fish is only part of the solution to the issue and it is important you
don’t ignore the need to improve the cover. Improving the cover is more
important than stocking bait fish if you were to prioritize the long-term
needs of the lake. This goes back to the need for proper habitat. Stocking
forage is a short term band-aid, improving the cover is a sustainable
solution. With proper cover in place, stocking forage fish becomes a much
better investment since they are being stocking into a much more balanced
eco-system. Stocking 1,000 lbs of adult Golden Shiners would be sufficient.
Budgeting to have Shiners stocked on a annual basis would provide a good
boost to the productivity of the fishery. The expense involved with the
improvements required will likely result in the need to focus on only a
couple improvements annually.
Harvesting bass and crappie annually while adding cover and stocking
forage as budget allows is the best approach to improving the quality of the
fishery.
Conclusion
Continue to harvest all intermediate size bass and crappie.
All bass between 8 and 14 inches should be removed until the target of
15 lbs of predator fish per acre have been harvested (annually).
Release all Bluegill caught.
Budget to improve fish cover throughout the lake.
Improve fish cover in ~24 locations throughout the lake.
Budget to stock Golden Shiners in the lake.
Stock 500 - 1,000 lbs of Shiners to the lake annually or as budget allows.