Arkansas Game and Fish Commission Crappie Management Plan
Arkansas Game and Fish Commission Crappie Management Plan February 28, 2002
ARKANSAS GAME & FISH COMMISSION
CRAPPIE MANAGEMENT PLAN
D. Colton Dennis,
Mike Gibson, Chief of Fisheries
The goal of crappie management is to provide quality
crappie fishing. Management efforts towards improving recreational crappie
fishing will be optimized within the context of a multi-species fishery by
accurately characterizing crappie population density and structure and
crappie populations through harvest regulations, stocking, and habitat
1. Develop standardized sampling methodology for evaluating crappie
2. Develop a set of biological criteria for identifying what a model crappie
population in Arkansas should resemble based on standardized sampling
procedures to manage both black and white crappie populations collectively.
3. Develop a Crappie Stock Assessment to provide a standardized means for
fisheries managers to make objective evaluations of population structure and
population trends over time.
4. Develop a set of biological criteria that would determine when or if
regulations would be appropriate for improving crappie population structure.
5. Develop guidelines and evaluate effectiveness of crappie supplemental
6. Evaluate need for stocking forage species such as threadfin shad when
crappie growth is limited.
7. Evaluate need for stocking predator species such as saugeye when crappie
overpopulation and stunting occurs.
8. Assess crappie habitat needs in Commission-owned and Federal water
lakes and implement appropriate habitat improvement projects.
9. Exploit opportunities to influence water management policy and
features on Federal water project lakes to improve crappie habitat.
Crappie collectively are the most sought after sport fish among senior
resident anglers (44%), and second to bass (largemouth and spotted) among
resident (34%) and non-resident (25%) anglers in Arkansas (Duda et al.
Combined, resident and non-resident anglers spend an estimated $92.6 million
annually fishing for crappie in Arkansas. Because of high angler interest
significant contribution to the State’s economy, the Arkansas Game and Fish
Commission has intensified its efforts towards developing a species plan to
optimize management efforts and enhance the quality of recreational crappie
fishing by characterizing and improving crappie population structure.
A standardized sampling methodology for sampling and evaluating crappie
populations was developed using trap nets. Trap netting will be conducted a
minimum of 30 net-nights per month from September through November in an
effort to collect sufficient numbers of crappie to allow population size and
A set of biological criteria was developed to define a model crappie
population in Arkansas based on standardized sampling results. Objectives
the five population parameters of density, growth, age structure, size
and recruitment were established by examining trap net data from fifteen
Arkansas lakes. Lakes varied from oxbows to large Corps of Engineer
impoundments and from relatively clear and infertile waters to very
lakes with dense algae or plant growth.
A good crappie population has a high density of desirable-size fish
for angler harvest. Further, it will have adequate and consistent
accompanied with sufficient growth to compensate for harvest.
An optimal crappie population in Arkansas will exhibit a growth rate of 201-
mm to 275-mm (8-11 inches) at Age-2+, have a size structure (percent >
above 30%, and show consistent recruitment. These metrics are minimally
sufficient to describe a good crappie population. Age structure, growth, and
mortality estimates are needed to determine the suitability for enacting
length limits and/or other harvest regulations.
A crappie stock assessment was developed based on estimates of density,
growth, age structure, size structure, and recruitment. Values for the five
parameters were established by examining trap net data from Arkansas lakes,
highest values were assigned to optimum measurements of each parameter.
Values assigned to each population parameter were summed to give an overall
rating for the crappie population condition. The Crappie Population
should provide a standardized means for fisheries managers to make objective
evaluations of population structure and population trends over time.
A set of biological criteria was developed to determine when or if harvest
restrictions would be appropriate for improving crappie population
Management strategies based on growth and mortality rates, and age and size
structure include adjusting crappie creel and length limits, management of
predators, lake fertilization, stocking, and control of aquatic vegetation
Angler preference is an important consideration when minimum length limits
are being examined as management strategies. The use of population modeling
programs will be used to predict long-term effects on crappie harvest prior
implementation of minimum length limits. Due to the various growth and
mortality rates of crappie populations across the state, statewide length
may be detrimental and result in substantial reductions in yield to some
Therefore, statewide length limits are not a recommended management strategy
for Arkansas crappie populations.
Guidelines for crappie supplemental stocking were developed, in which
stocking rates are determined by lake size. New lakes have the highest priority
for crappie stockings. Supplemental stockings in other lakes will be based on
technical analysis of cove rotenone population samples and/or trap netting and
social needs relevant to the fishery. Lakes over 4,050 ha, including Corp of
Engineer impoundments, should be stocked through the nursery pond system.
Crappie should not be stocked in lakes during years of high recruitment, since
supplemental stocking is not likely to make a significant contribution to the
naturally produced, strong year-class. Also, crappie should not be stocked in
lakes where Age-0 to Age-1 mortality is high, because it is likely that
supplemental stocking will have a similar high mortality rate due to poor
conditions such as lack of adequate forage, habitat, or high predation.
Environmental manipulation techniques such as lake fertilization, water level
manipulation, and habitat improvement will be used in tandem with regulations
and stockings to improve crappie populations where these techniques are
appropriate. Habitat assessments are to be performed on Commission-owned and
Federal water project lakes to determine crappie habitat needs. Feasibility
plans are to be drafted and implemented to address these needs as budget and
resources allow in an effort to improve crappie habitat statewide.
No management plan is complete without proper evaluation, and management
strategies suggested in this plan should be appropriately evaluated after
exploitation studies have been initiated, population modeling has been
conducted, harvest restrictions have been imposed, or creel surveys have been
completed. Evaluation of additional trap netting data using the Crappie Stock
Assessment will yield further information regarding the effectiveness of the
Natural mortality rates of Age-0 to Age-1 crappie should be derived by
fishery managers to assess where supplemental stockings will be most
beneficial. Fishery managers should also re-evaluate current crappie minimum
length limits on Arkansas lakes using population modeling programs. Other
sampling techniques such as using larger 8’ x 8’ or 6’ x 6’ trap nets and
spring/fall electrofishing should be explored where standard trap net gear has
been ineffective at sampling the crappie population. Handling and hauling
mortality of crappie must be estimated and reduced by hatcheries to minimize
post-stocking mortality. Acceptable marking techniques for identification of
stocked crappie also need to be investigated. Once a desirable marking
technique is accepted, future contributions of stocked fish to year-classes can
A Crappie Recruitment Model is needed to determine what variables are
having the greatest impact on crappie recruitment in Arkansas waters. The
model would potentially help fishery managers identify those problems in
reservoirs where corrective management could be applied, and would also help
in predicting missing year-classes and thus, supplemental stocking
guidelines on an annual basis.
Finally, the purchase and replacement
of boats, motors, trap nets, funding for exploitation/tag reward studies,
and continued workshops and application of fish population modeling is
needed for successful implementation of this plan.
Both black crappie Pomoxis nigromaculatus and white crappie P. annularis
are found throughout Arkansas (Robison and Buchanan 1988). Both species prefer
quiet waters, and are almost always found near cover such as brush piles, tree
tops, standing timber, and aquatic vegetation. Black crappie prefer cooler,
deeper waters and seem to dominate in clear, vegetated, acidic waters, while
white crappie tend to dominate in eutrophic (richer), more turbid, alkaline
waters. Crappie collectively are the most sought after sport fish among senior
resident anglers* (44%), and second to bass (largemouth and spotted) among
resident (34%) and non-resident (25%) anglers in Arkansas (Duda et al. 2000).
Questionnaire results also indicated that a large percentage of anglers (62% of
senior residents, 48% of residents, and 43% of non-residents) choose to consume
the different species of fish they catch (Duda et al. 2000)
In 1996, resident anglers spent $191.3 million and non-resident anglers
spent $110.4 million fishing in Arkansas waters (Maharaj and Carpenter 1997).
Combined, resident and non-resident anglers spend an estimated $92.6 million
annually fishing for crappie in Arkansas. Because of high angler interest and
the significant contribution to the State’s economy, the Arkansas Game and Fish
Commission has intensified its efforts towards developing a species plan to
optimize sampling and management strategies towards improving the quality of
recreational crappie fishing. For years, biologists believed lakes with large
numbers of undersized crappie were the result of overpopulation and stunting
(Goodson 1966; Ming 1971). As biologists began to look more closely at crappie
age-and-growth, they often found over-harvest instead of over-population (Webb
and Ott 1991). Colvin (1991) reported over-harvest of crappie in a large
Missouri reservoir. However, this is not always the case as Reed and Davies
(1991) recommended against size restrictions to protect the crappie fishery
from over-harvest, because high natural mortality would have nullified the
benefits of a delayed harvest.
Past crappie management in Arkansas was seldom based on well-defined
objectives developed from the three rate functions of recruitment, growth, and
mortality, which reflect crappie abundance and size structure. Often, crappie
received little or no direct management. A standardized approach to
characterizing the state’s crappie populations was needed to provide reliable
information. A research team was formed in 1994 to develop criteria to best
characterize crappie population structure and optimize management efforts.
Fifteen lakes were sampled with trap nets between 1989 and 1993 to gather data
to develop this plan (Table 1). Lakes varied from oxbows to large Corps of
Engineer impoundments and from relatively clear and infertile waters to very
productive lakes with dense algae or plant growth.
Successfully managing crappie populations requires understanding
and manipulating processes controlling recruitment. Recruitment is the
number of crappie surviving their first year of life, and is influenced by
spawning success, environmental conditions (temperature, food availability,
water level fluctuation, turbidity, etc.) and predation on young-of-the-year
(YOY) crappie. Arkansas’ lakes undergo fluctuations in water levels,
temperature, turbidity and organic inputs. These factors greatly affect the
success of crappie spawns and produce natural variations in fry production.
Under proper circumstances these variations are evident later in recruitment
and eventually in age structure.
Cyclic and highly variable recruitment is a principal management problem in
crappie fisheries, which generally produce strong year-classes every 3-5
years (Swingle and Swingle 1967). Results from Allen and Miranda’s (1997)
crappie age-structure population model suggested that a specific combination
of stock abundance and environmental conditions produced cyclic recruitment
in crappie populations. These factors may act in combination resulting in
high recruitment when stock abundance is low and environmental conditions
are favorable, and low recruitment when stock abundance is high and
environmental conditions are unfavorable. In addition, modeling suggested
that even with favorable environmental conditions, production of a strong
year class might lead to reduced or only average recruitment in subsequent
(1-5) years. The predator population also affects fry/juvenile mortality and
subsequent recruitment. We speculate that a high-density bass population
results in low crappie recruitment due to intense predation (high natural
mortality), in which surviving crappie are fast growing and reach large
size. Many fishermen would prefer this situation to catching numerous
smaller crappies (AMRA 1988). An example is Bear Creek Lake, which holds a
dense population of 250mm-325mm (10-13”) largemouth bass, and shows low
crappie recruitment and rapid growth with average size of 320-mm (12.5”) at
age 2+. In contrast, Lake Greenlee has low bass density and shows crappie to
be * anglers who have purchased an Arkansas Senior Citizen (65+) fishing
license overpopulated, slow growing, and seldom reaching more than 150-mm
(6”) in length as adults.
Dense predator populations have been shown to be inefficient in controlling
YOY crappie when turbidity levels are high or thick vegetation is present.
Channel scar lakes or shallow lowland lakes are perhaps Arkansas’ most
fertile lake type and often have dense vegetation and/or turbid water used
as cover by many YOY fishes. These lakes show good to high recruitment
values and low mortality of YOY crappie, which results in low growth rates.
Recruitment must be controlled to properly manage these lakes. Added fishing
pressure and relaxed limits may not be sufficient to control overpopulation.
Control of vegetation and turbidity may provide an answer. In lakes
containing moderate densities of largemouth bass and low crappie density,
natural fluctuations in crappie production show up as inconsistent
recruitment and missing year classes. Lakes Beaver, Bob Kidd, Nimrod, and
Horseshoe show large variations in age structure due to inconsistent
recruitment. The most appropriate management strategy in these situations
may be to manage the habitat (water level, cover, fertilization) to enhance
spawning success and recruitment.
Harvest regulation is one possible way to influence crappie
populations when exploitation (angler harvest) is high. However, only under
conditions of rapid crappie growth and low natural mortality will minimum
length limits improve yield (average weight of fish harvested) in crappie
populations. Prior to the implementation of minimum length limits,
population-modeling programs should be used to predict long-term effects on
the crappie population. Modeling results can be evaluated by subsequent
field data collections. Knowledge of angler preference when minimum length
limits are being investigated should also be an important consideration for
fishery managers in the decision-making process.
Standardized Sampling Procedures
Net Set Procedures
Trap net samples are described as the most efficient and precise means of
sampling crappie. Boxrucker and Ploskey (1988) found trap nets to have a
per unit effort (CPUE) and lower within season variability than either
electrofishing or gill
netting, and were the only types to adequately sample YOY crappie. Fall trap
best represented population structure. McInerny (1988) found age and size
black crappie from fall trap netting similar to that harvested by fishermen
same season. Miranda et al. (1990a) found a significant correlation between
crappie abundance from spring trap netting and springtime angler harvest per
The primary objective of trap netting is to collect sufficient numbers of
allow population size and age structure analysis in lakes with significant
fisheries. Trap netting may also be used to collect fish for mark-recapture
and exploitation estimates.
Temporal variations in size and age structure of crappie are evident within
trap net samples in Arkansas. A higher percentage of YOY are caught in early
larger, older fish are caught in late fall. Better estimates of population
be obtained by sampling throughout the fall. All fish will be aged by
This method results in less error and variability than the scale method (Boxrucker
Trap nets are constructed with two (2) 3’ x 6’, 5/16” diameter, steel frames
center braces and four (4) 2.5’ diameter hoops of 3/8” steel. The 3’ x 6’
frames are 30”
apart, and the first hoop is 32” from the second frame. The hoops are 24”
second 3’ x 6’ frame has a slit throat and the first hoop has a 6” throat.
The net material
is 1/2” square NO.105 L knotless nylon, netset treated. The cod end of the
net has a
string closure with a 5’ No. 5 braided nylon string.
The leads are 1/2” square No. 105L knotless nylon hung 14 meshes per foot on
60 nylon twine, netset treated with 2” x 1.5” cork floats spaced at 3’
intervals and 1.5 oz.
weights spaced at 2’ intervals. The leads are 50’ in length and 3.5’ deep
exception that shorter leads can be used near steep drop-offs. Leads are
attached to the second 3’ x 6’ frame center brace.
Alternatively, Miranda et al. (1996) reported that floating trap nets with
frames, and longer and deeper leads than the standard 3’ x 6’ frame with 50’
be necessary in larger, deeper reservoirs where catch rates are low. These
large 8’ x 8’
frame floating trap nets with 200’ leads resulted in larger sample sizes
sampling effort when fished in habitats that previously were not sampled
standard trap net gear.
Although the larger 8’ x 8’ frame net caught more crappies than the standard
fishing the net can sometimes be problematic. The net is bulky, and because
of its size
and weight can be difficult to handle when wet. Wind and wave action can
nets to be disabled, especially in open-water sets. The large nets are also
floating in open waters where they are likely to be encountered by boaters.
Isaaks and Miranda (1997) developed a smaller 6’ x 6’ frame floating trap
net with a
150’ lead that is easier to handle than the larger 8’ x 8’ nets. The 6’ x 6’
net resulted in
catch rates that were lower than the 8’ x 8’ net, but significantly greater
nets. Therefore, the 6’ x 6’ floating nets may be a compromise between the
x 6’ nets and the more cumbersome 8’ x 8’ floating nets.
Trap netting will be conducted during the months of September, October and
November when water temperatures are between 16 - 26 degrees C (61 – 79 °F).
Minimum effort is 30 net nights per month, or 150 crappie greater than Age-0
less than 810 hectares (2000 acres), or 250 crappie greater than Age-0 for
hectares or larger.
Nets should be set perpendicular to crappie movement. Suggested areas
gradually sloping lake bottoms at the mouths of coves, off points, or areas
old river channels. Net sets in or near standing timber or where the leads
break over a
sharp drop-off should be avoided. To reduce variability over time, the same
should be netted from year to year. Global Positioning Systems (GPS) can
also be used
to record net site locations that are consistently more productive.
NET SET PROCEDURES
Nets should be set at least one hour prior to sunset. If nets are left in
location, then they should be checked at the same time each day if possible.
nets should not be fished at the same set more than two nights in
All crappie collected are differentiated by species, and total length and
each fish recorded. When large numbers (>200) of fish <80mm are collected,
subsamples of 25% by number are permitted.
Otoliths will be removed for age determination from a minimum of 10 fish per
(1-inch) length group for each species. Otoliths will be read using a
microscope or microfiche. A micrometer is optional, but is required for back
All trap net sampling data including information obtained from otolith
readings will be
recorded and processed using the Fisheries Division trap net software,
There are several problems inherent to this sampling scheme. These problems
should not influence recommendations; however, fish managers should be aware
these limitations and make changes in sampling schemes when necessary.
Crappies are growing during the sampling period from September through
November. Differences in lengths during this period may obscure
histograms and length-at-age determinations. Sample variance of
increase with the width of the sampling window. Growth during the sample
especially critical for younger age groups. This may cause problems when
population statistics from year to year and make it more difficult to
Young of the year crappie are typically caught in higher proportions earlier
fall, and larger, older crappie are generally caught later in the fall. This
necessary to sample over the entire 3-month period to obtain a
Should the minimum number of crappie be caught early in the sampling season,
older component may not be represented in proportion to their abundance in
Additionally, the percentage of crappie of a given age within a size group
be estimated within 10%, if 10 fish per size class are aged. When more
required, more or all fish should be aged. Sampling from September through
calculating length at a standard age (back calculations), and aging all fish
Developing appropriate objectives for population parameters combined with
standardized sampling procedures are vital to achieving effective fisheries
(Anderson, 1975). In the last few years, considerable attention has been
given to the
use of structural indices to describe and classify population structure.
Colvin and Vasey (1986) developed a method of assessing white crappie
populations in Missouri based on fall trap netting. Their system is based on
point values assigned to estimates of density, growth (length-at-age), age
structure, and recruitment calculated from fall trap net samples. A 0-10
assigned to each of the five population parameters. The five scores are then
give an overall index of population condition. This assessment is currently
evaluate crappie population structures in Missouri (M. Colvin, Missouri
Conservation, personnel communication).
A primary objective of the Crappie Management Plan was to develop a stock
assessment index to evaluate crappie populations in Arkansas (Table 2).
Stock Assessment Index was selected as a model from which to begin. The
index, however, was developed for large reservoirs and white crappie
Arkansas has both species of crappie existing in large impoundments as well
lakes. Therefore, the Missouri Stock Assessment Index was adjusted to
for these differences. Trap net data collected between 1989-1993 from
lakes, which varied from oxbows to large Corps of Engineer impoundments,
to generate the model.
Arkansas’ lakes contain mixed populations of white and black crappie that
managed as a group for regulatory simplification and so are combined for
assessment. Values (1-10) are assigned for ranges of five population
(density, growth, age structure, size structure and recruitment) calculated
from fall trap
net samples. Highest point values are assigned to optimum measurements of
parameter. Because crappie density values varied greatly among the fifteen
sampled, and recruitment values are sometimes a poor indicator of actual
abundance, these two parameters have been weighted disproportionally in the
assessment. Point values assigned to each population parameter are summed to
an overall rating for the crappie population condition. However, the values
individual parameters are more useful for management purposes than the final
The Crappie Population Assessment (Table 2) should provide a standardized
means for fisheries managers to make objective evaluations of population
population trends over time in specific lakes. The assessment can also be
compare indices between similar lake types such as Bull Shoals and Norfork.
CHARACTERISTICS OF A GOOD CRAPPIE POPULATION
A good crappie population has a high density of desirable-size fish
angler harvest. Further, it will have adequate and consistent recruitment
with sufficient growth to compensate for harvest.
Density is a function of recruitment and mortality. Catch per trap net-night
and older fish in fall samples is used as an index of density. Age-0
excluded because trap nets do not sample Age-0 in proportion to their
the presence of a large year-class could bias the sample.
Catch rates of 10 to 39 Age-1 and older crappie per net-night are considered
optimal for our purposes. However, when sufficient forage is available and
good (mean length @ Age-2+ >250mm) higher densities are acceptable. Lower
are assigned to the same catch per net night if growth is poor (mean length
Density, fish movement, weather conditions, and other factors influence trap
catch rates. Lake morphometry, water levels, presence of cover, etc
efficiency. Catch rates may not always represent actual density. For this
several years of data are desired when analyzing crappie populations.
Population density influences the ratings of 2 other parameters. When
crappie are good (>20 Age-1+ and older per net-night), broader ranges of
and size structure are accepted as desirable.
Growth rate (mean length @ Age-2+) should be a good indicator of the
forage relative to crappie abundance. Growth influences the size and age
structure of a
population and affects sizes of fish available for harvest by anglers. In a
population, fish should reach a minimum harvestable size in a reasonable
period of time.
A good crappie population should have a growth rate between 201-mm (8”)
and 275-mm (11”) at Age-2+. Current data shows Arkansas lakes are capable of
growth rates within this range. Crappies above 225mm begin to add weight at
rate and are valued more highly by fishermen.
High growth rates (> 275-mm @ Age 2+) are associated with lower than optimal
densities and age structure. However, higher growth rates are acceptable
is high since an adequate forage base must be present to produce good
growth (=200-mm @ Age 2+) may be attributed to other trophic levels other
fishes, since crappie less than 150-mm (6”) forage primarily on plankton and
Growth influences the value assigned to the density rating. Density is rated
when accompanied by good growth because density is not likely to be the
Growth indirectly influences age structure by determining at what age
vulnerable to angler harvest. Faster growing crappie become vulnerable to
mortality sooner. Growth rate also influences the value of recruitment.
rated higher when accompanied by good growth since density is not likely to
The age structure of a population is the result of recruitment and mortality
and natural). Age structure is most useful as an indicator of mortality and
may be our
best indicator of recruitment, although it takes 1 to 2 years for a year
class to show an
effect. The management objective for age structure is at least 10% of the
population comprised of Age-3 and older crappie. Colvin and Vasey (1986)
percentage of Age-4 and older as an indicator of age structure for
populations. Boxrucker (1989) found the highest mortality of Oklahoma
crappie to occur
before Age-3. Current data indicates Arkansas’ annual mortality is similar,
percentage of Age-3 and older crappie (excluding Age-0 fish) is used to
Higher assessment values are assigned to age structure when growth is good.
adequate forage base as indicated by good growth will allow for a higher
older, larger fish. High age structure (>25% of adult fish 3+ or older)
recruitment, relatively low angler harvest, and a higher proportion of
larger fish when
growth is good. Low age structure (<10% of adult fish 3+ or older) combined
growth indicates relatively high angler harvest, high natural mortality,
year-classes. Inconsistent recruitment and single year-classes moving
population most likely cause variability in age structure within a lake.
Size structure, the percent of fish greater than 250-mm (10”) excluding YOY,
indicates the percentage of desirable fish available to the angler. Size
dependent upon recruitment, growth rate, and mortality. It is related to age
since older fish are larger whenever there is sufficient forage.
Size structure is considered optimal if 30-59% of crappie are greater than
250mm (10”). Fewer points are awarded to higher values of size structure
high percentage of large crappie also indicates lowered numbers of younger
possible missing year-classes. Missing year-classes can cause negative
effects to the
size structure for several years.
High scores for size structure are assigned to a wider range of percentages
density is high. In a dense population, high percentages of large fish are
less likely to
indicate missing year-classes.
Size structure assessment is useful in predicting the effectiveness of a
For example, a 10” minimum length limit would be less effective when the
is either very low or very high relative to the age structure. A truncated
dominated by numerous small fish, relative to age structure, indicates a
lack of forage
and possible stunting. A size structure dominated with a few, large crappies
indicate a missing year class.
Recruitment, the number of (YOY) crappie per net-night, is variable between
and may not accurately describe abundance. Within the same lake, however,
recruitment should be consistent from year to year.
Catch rates of 4 to 29 crappie YOY per net-night is considered optimal.
Recruitment values provide insight into year-class strength. When growth is
values are given to a wider range of percentages because density is less
likely to be the
limiting factor. Low recruitment (very near 0) probably indicates low
densities of YOY
and potential missing year-classes, while high values are often associated
that display higher crappie densities and slower growth. Boxrucker (1989)
that excessive recruitment may adversely affect growth, but is sometimes
usually restricted to the first and second year of growth. Low recruitment
year-classes also reduces the numbers of fish available to fishermen and the
Recruitment directly affects density, size structure and age structure.
trap nets may not sample Age-0 in proportion to their true abundance, the
this metric to the assessment value is reduced. Age structure may be a more
indicator of recruitment, although, it takes 1 to 2 years for a year class
to show an effect.
In summary, an optimal crappie population in Arkansas will exhibit a growth
201-mm to 275-mm at Age-2+, have a size structure (percent > 250-mm) above
and show consistent recruitment. These metrics are minimally sufficient to
good crappie population. Age structure, growth, and mortality estimates are
determine the suitability for enacting minimum length limits and/or other
Of the 12 lakes that we have more than 1 year’s data, 4 lakes (Overcup,
Brake, DeGray, Lake Charles) exhibited metrics described for a good
Creek Lake has a high size structure assessment value, but a high growth
indicate less than optimal density. Horseshoe and Felsenthal both display
rates and possible stunting. Lakes Beaver, Bob Kidd, Nimrod, and Horseshoe
large variations in age structure probably due to inconsistent recruitment
Harvest regulations and management strategies are recommended to shift
populations toward what is considered a good population, as previously
(Figure 1). This chart outlines a consistent and objective way of assessing
populations, which will help fish managers identify problem areas and direct
towards needed research and management activities. Harvest regulations
angling exploitation is significantly impacting the size and age structure
of a crappie
population. Crappie 10-inches and larger provide considerably more benefit
than do smaller crappie. Ten inches was considered to be the minimum size
be harvested by anglers based on length-weight relationships showing that
black crappie begin adding proportionally more weight per unit length when
they are 8 or
9-inches long. According to Mark Zurbrick, (Missouri Department of
comm.), fifteen 10-inch crappie will weigh more than twenty 9-inch crappie.
(1990) found that 8-inch crappie would double in weight if allowed to reach
Restrictive size limits can perform an important role in managing crappie
The success of restrictive size limits meeting certain
managementobjectives for crappie populations has varied among water bodies (Colvin
1991; Larsonet al. 1991; Webb and Ott 1991; Mitzner 1995; Boxrucker 1999).
probably the most effective tool for controlling crappie harvest, because
which are likely to be acceptable to anglers (>15 fish/day) do not
crappie population characteristics (Allen and Miranda 1997). Length limits
increase average weight of fish harvested by anglers without a considerable
yield. Allen and Miranda (1995) evaluated published data from crappie
across the southeastern and Midwestern U.S., and indicated that only under
of rapid growth and low natural mortality would minimum length limits
improve yield in
crappie populations. In addition, crappie populations with slow growth or
mortality are probably best managed without a length limit.
Crappie populations are dynamic and greatly influenced by annual
Evaluation of a crappie length limit may be misinterpreted when population
survey data is used, since they are influenced by highly variable
(1991) reported that poor recruitment prevented an accurate assessment of a
length limit in a Missouri reservoir. Webb and Ott (1991) discovered that a
minimum length limit improved crappie fisheries in three reservoirs,
after the limit was established indicated that it was short-lived (3-4
The use of population modeling programs such as MOCPOP or FAST can assume
constant or variable recruitment and predict long-term effects on harvest
prior to the
implementation of minimum length limits. The results of modeling can then be
by subsequent collections of field data. Maceina et al. (1998) effectively
Beverton-Holt equilibrium yield model to predict the effects of four
length limits in Weiss Lake, Alabama. They found that a 10-inch minimum
would increase yield of crappie, only if conditional natural mortality rates
were less than
35%. However, anglers would also have to accept a decrease in their creel
exchange for the increased average weight of crappie.
Recruitment from fry into the adult population and subsequent growth appears
partially dependent on predators, primarily largemouth bass. High predator
may reduce crappie recruitment due to intense predation, in which surviving
fast growing and reach large size.
In lakes with dense, slow growing crappie, relaxed creel limits could be
aquatic vegetation or turbidity is causing inefficient predation, these
also be controlled.
Finally, anglers on a particular water body may desire higher numbers of
fish, and knowledge of angler preference when minimum length limits are
investigated should be an important consideration for the fishery manager in
decision-making process. Due to the various growth and natural mortality
crappie populations across the state, statewide length limits may be
result in substantial reductions in yield to some fisheries. Therefore,
limits are not a recommended management strategy for Arkansas crappie
The need to improve crappie growth rates in reservoirs has been the focus of
management efforts. The strategies used typically involve manipulation of
predator/prey balance. This is especially challenging when dealing with
species such as
crappie which are both planktivorous and piscivorous (after reaching
inches in length) for significant portions of their lives. A management
favorably affects the planktivorous life stage may have no effect or
possibly a negative
effect on the piscivorous life stage.
The introduction of threadfin shad as supplemental forage for a crappie
has been met with mixed results. Supplemental stocking of threadfin shad may
adversely impact young crappie in a population. Competition for plankton
threadfin shad and young crappie can occur if shad densities are too high.
Game and Fish Commission cut their stocking rate of threadfin shad from 25
to 12.5 per hectare because of possible problems with competition for
Osage Lake (Mosher 1984).
Over winter survival and availability of threadfin shad broodstock are viable
for the fisheries manager. Sustained winter water temperatures below 41
Fahrenheit are lethal to threadfin shad and will occur in Arkansas lakes
winters.Threadfin shad have also been shown to be valuable prey for crappie (McConnel
and Gerdes 1964; Bartholomew 1966; May et al. 1975; Hepworth and Pettengill
Some studies have documented growth of larger piscivorous crappie following
supplemental stocking of threadfin shad. These growth gains were most
systems where forage was deficient before threadfin shad introductions.
Arkansas lakes and reservoirs already contain adequate shad forage, shad
may not be beneficial.
Boxrucker (1987) reported the population of crappie in Thunderbird
Oklahoma improved after the introduction of saugeye. It appeared the
crappie population structure was the result of a density dependent growth
resulting from predation on crappie by adult saugeye. Horton and Gilliland
that saugeye in Thunderbird Reservoir began feeding on crappie after
(14 inches) and that crappie comprised more than 60% of the diet of saugeye
than 525-mm (21 inches). Saugeye became significant predators of crappie
reaching 457-mm (18 inches). This information, along with concerns regarding
overharvest of “needed predators” led to the implementation of an 18-inch
for Thunderbird Reservoir saugeye.
Fisheries managers should consider interactions of adult saugeye and
predator populations. In systems with high shad densities, crappie may not
utilized as forage by the saugeye. If data from Arkansas lakes indicates
populations are not effective predators due to high turbidity or thick
might also be poor at controlling crappie density.
CRAPPIE STOCKING GUIDELINES
Supplemental crappie stocking has long been used as a management strategy
when overexploitation, increased fishing pressure, or poor recruitment has
led to a
decline in the crappie population. Currently, the Arkansas Game and Fish
stocks approximately 0.5 million black and white crappie combined in many of
and reservoirs annually to improve crappie fisheries. However, Murphy and
(1986) suggest that several factors, including post-stocking survival,
success of any stocking program.
Post-stocking survival of hatchery-reared fish is related to many variables
fish size and condition, pre- and post-stocking environments, genetics, and
transportation processes (Mazeaud et al. 1977; Parker 1986; Williamson and
Carmichael 1986; Wallin and Van Den Avyle 1995). Estimates of initial
mortality rates of crappie reported from only a few studies in the
literature ranged from 0-
Sammons et al. (2000) assessed initial post-stocking mortality, year-class
contribution, and predation upon recently stocked crappies in seven
impoundments. Their initial post-stocking mortality rates for crappie ranged
averaged 16%, and were most heavily influenced by extreme hauling densities
Exposure to stresses such as poor water quality and overcrowding during
hatchery ponds likely influence initial crappie survival and should be
improve the stocking process.
Year class contribution is commonly used to evaluate the effectiveness of a
program (Boxrucker 1986; Heidinger and Brooks 1998; Sammons et al. 2000).
class contribution and survival of stocked fish has been shown to vary from
lake to lake
and from year to year within the same waters (Fielder 1992; Elrod et al.
and Brooks 1998; Sammons et al. 2000). Crappie year class contribution from
supplemental stocking ranged from 0-93% in seven Tennessee impoundments, and
indicates that supplemental crappie stocking is not successful in all
reservoirs (Sammons et al. 2000). Angler creel data also indicated that in
Tennessee reservoir only 1% of stocked crappies since 1995 had contributed
fishery through 1998, while in another reservoir stocked crappies
significantly to angler’s creel during the same time. Predation by resident
stocked crappie was a primary factor suspected of limiting stocking success
Predation on stocked fishes by resident predator fishes has been commonly
theorized (Fielder 1992; Elrod et al. 1993). The occurrence of stocked
predator stomachs containing food ranged from 14 - 41% in five Tennessee
(Sammons et al. 2000). Size of stocked crappie may have increased predation
because stocked black crappie were on average 30% and 40% smaller than black
white crappies found in the wild at the time of stocking. Sammons et al.
suggested that high predator densities in some Tennessee impoundments are a
significant factor limiting supplemental crappie stocking success.
Success of stocking contributions have been shown to vary with fluctuations
natural year-class strength, in which highest contributions from stocked
fish developed in
years when natural recruitment was low (Heidinger and Brooks 1998). In
Reservoir, Tennessee where supplemental crappie stocking was shown to be
successful, natural recruitment was considered below average (Sammons et al.
Hence, when strong year-classes are present in the fishery, stocking
less likely to be effective.
The effectiveness of stocking crappie to supplement missing year classes or
recruitment is currently being evaluated in Arkansas (S. Lochmann,
Arkansas at Pine Bluff, unpublished data). Early results suggest that there
some clear guidelines for stocking crappie in Arkansas’ waters.
1. Crappie should be stocked according to the most successful or dominant
species in the lake. If the lake is dominated by a particular species, then
environmental conditions of the lake are apparently more favorable or
that species recruitment and survival.
2. Crappie handling and hauling mortality needs to be minimized to 10-20%.
Handling/hauling mortality estimates in the Lake Chicot Crappie Study ranged
1-40%, while the Tennessee study ranged from 0-95% with an average of 16%.
Unless handling/hauling mortality is minimized, time, money, and manpower
being misappropriated by supplemental stocking crappie in Arkansas waters.
3. Crappie should not be stocked in lakes where Age-0 to Age-1 mortality is
the annual mortality rate of Age-0 crappie in the natural population is
high, then it is
likely that stocked crappie will have a similar high mortality rate due to
conditions such as lack of adequate forage, habitat, or high predation.
managers can determine mortality rates of Age-0 to Age-1 from cove rotenone
samples conducted over time.
4. Crappie should not be stocked in lakes during years of high natural
because supplemental stocking is not likely to make a significant
contribution to the
year class. For example, if a lake has a natural reproduction of 500
stocking 50 fish/ha (10%) would not make a reasonable contribution to the
class. This practice would allow for crappie supplemental stockings to be
reallocated to lakes where natural reproduction was unsuccessful.
There is good evidence that supplemental stocking of crappie during years of
unsuccessful reproduction and suitable conditions, such as low initial
mortality and decreased predator densities, can make up a reasonable high
of missing year-classes (Sammons et al. 2000). Currently, the Arkansas Game
Commission stocks approximately 0.5 million black and white crappie combined
of its lakes and reservoirs annually to improve crappie fisheries. The
supplementally stock a lake will be based on a combination of technical
sampling data and social considerations. Lakes with high natural mortality
occurrence of Age 0 crappie will be considered poor candidates for
stocking. New lakes and lakes exhibiting poor natural spawns are considered
candidates for stocking. Crappie should be stocked in the fall/winter during
the year in
which natural recruitment was poor in an effort to make a significant
contribution to the
missing year class.
Prioritization of lakes is warranted due to requests for crappie being
greater than the
number produced by the hatchery system. Therefore, new and renovated lakes
the highest priority for crappie stockings and should be stocked at a rate
at or near
250/ha (100/acre). Supplemental stocking justification varies on technical
needs as well as hatchery capabilities. Stocking rates are provided as
guidance only to
be considered in the matrix of population needs, social needs, and hatchery
Lakes under 1,215 ha (3,000 acres) will be given next priority and will be
stocked at a
rate of up to 125/ha (50/acre). Finally, lakes ranging in size from 1,215 to
(10,000 acres) will be stocked at a rate of up to 62/ha (25/acre). Lakes
over 4,050 ha,
including Corp of Engineer impoundments, should only be stocked through the
pond system to optimize hatchery production space.
Nursery ponds will be utilized for supplemental crappie stocking when
reservoirs, including Corps of Engineer impoundments, where stocking is
This will free up hatchery pond space for other species due to the length of
production (March-October) and also decrease handling/hauling mortality.
crappie may not be needed every year if lakes are capable of producing
natural spawns, therefore, District Fisheries personnel may choose to
space to other species, which could benefit from the nursery pond. District
personnel are strongly encouraged to use other means such as lake
level manipulation (controlled winter drawdowns), and habitat improvement to
crappie recruitment. Crappie brood stock collection for the nursery ponds
will also be
the responsibility of District Fisheries personnel.
Lake fertilization is a widely accepted technique used to improve fish
The fertility or richness of the water determines the productivity of the
lake, and a more
productive lake will support more fish. Fertilizer increases lake
stimulating the growth of microscopic plants known as phytoplankton.
the basis of the food chain and is a primary food source for many larval
Increases in phytoplankton will increase the production of zooplankton,
increases fish production. This is especially important to crappie, which
planktivorous feeders until they reach a length of 150-mm (6-inches) and
then switch to
a more piscivorous diet. Upper and Lower White Oak Lake has been fertilized
1978 and 1988 respectively, and has resulted in a 4-5 fold increase in the
crappie YOY/hectare produced since the fertilization program began (D.
Controlled winter drawdowns administered every four to five years is an
low cost management tool that provides several positive benefits to a
Nutrients tied up in exposed substrate are oxidized and released back into
when the lake is refilled, resulting in a natural lake fertilization.
Reduced lake area
concentrates fish and allows for heavy crappie predation on forage species
increases in angler success and harvest. Winter drawdowns are also useful in
controlling, by freezing, undesirable or expanding aquatic vegetation. For
effectiveness, drawdowns should be conducted from August through January and
expose from 40-50% of the lakebed, which can usually be achieved with a 4-6
Fishery biologists have long suspected that reservoir hydrology influences
reproductive success and contributes to the cyclic nature of these
reproduction and recruitment of fishes has been linked to years when high
provided more spawning sites and protective cover for larval fish (Bennett
Bross 1969). Side channels and backwater areas have been shown to provide
habitat for a variety of fish species (Bade 1980; Pitlo 1992).
Drawdowns or dewatering of backwater areas during spawning can result in
reductions in habitat size and quality, including temporary loss of the
littoral zone and its
associated vegetation. The temporary elimination of the littoral zone can
also result in
the loss of juvenile fish, because they use littoral zone aquatic vegetation
as shelter from
adult piscivores (Werner et al. 1983). Dewatering can also reduce
spawning substrate, and expose nests with eggs and larval fish to drying
Ploskey (1986) found that spawning success for most littoral species was
related to water level increases during the spawning period because
habitat was produced for adults, and increased food and habitat resources
available for larval fish.
It is widely recognized that management strategies designed to improve
populations and harvest is dependent primarily upon water-level management.
Therefore, the Arkansas Game and Fish Commission will actively pursue
to positively influence water control policy and operations on Federal water
to benefit crappie fisheries.
Lake managers have long recognized the advantages of structure to attract
hold fish. The primary purpose of fish shelters or attractors is to
congregate fish to
improve fishing success for anglers. Fish can also be encouraged to spawn
provided with good spawning substrate.
Suitable shelters can be constructed from a variety of materials. Brush,
beds, rock piles, standing timber, and shoreline vegetation all make good
Establishing native aquatic vegetation in the littoral zone is particularly
impoundments that lack fish cover, and is currently being studied on Greeson
Shoals lakes in Arkansas (C. Horton, AGFC, personal communication).
The placing of fish attractors in large impoundments has been shown to
catch rates and harvest of fish. The Bull Shoals/Norfork Fish Cover Project
fish attractors containing over 70,000 trees (M. Oliver, AGFC, personal
The attractors covered 65ha (160ac) of lake bottom and extended 53 km (33mi)
shoreline. Scuba inspection and angler reports indicated that the attractors
successful in congregating fish and improved fishing and spearfishing over
areas. Short-term evaluation of fish attractors in seven Florida lakes
indicated that areas
with attractors produced significantly higher angler catches than control
number and weight of fish increased after the addition of artificial
structures in Wewoka
Lake, Oklahoma (Wright 1979).
Brush shelters have been shown to be more effective than most other
used to construct attractors. Reef construction from tires, brush, and
cement blocks in
Lake Tohoekaliga, Florida revealed that more fish were observed and caught
brush than other materials, but all types of attractors congregated more
fish than open
water control areas.
More recently several artificial shelter designs have come on the market
made from plastic or synthetic materials. Fish attractors made from PVC
experimented with in Lake Chicot in 1985, and more recently heavy duty snow
was used to attract and hold fish. Both materials were successful in
and resulted in increased angler success (J. Smith, AGFC, unpublished data).
Habitat assessments are to be performed on Commission-owned and Federal
project lakes to determine crappie habitat needs. Habitat assessment
protocols are to
be developed and feasibility plans are to be drafted and implemented to
needs as budget and resources allow. Fisheries Division will actively pursue
opportunities to implement appropriate crappie habitat improvement projects
general goal of improving habitat statewide.
1. No management plan is complete without proper evaluation. Management
strategies suggested in this plan should be appropriately evaluated after
studies have been initiated, population modeling has been conducted, harvest
restrictions have been imposed, or creel surveys have been completed.
of additional trap netting data using the Crappie Stock Assessment will
information regarding the effectiveness of the management plan.
2. Natural mortality rates of Age-0 to Age-1 crappie should be derived by
managers to assess where supplemental stockings will be most beneficial.
3. Handling and hauling mortality of crappie should be estimated and reduced
hatcheries to minimize post-stocking mortality to 10-20%.
4. Crappie marking techniques, such as six-hour oxytetracycline baths,
investigated for supplemental stock identification purposes. Once a
marking technique is accepted, future contributions of stocked fish to
can be evaluated.
5. Fishery managers should re-evaluate current crappie minimum length limits
population modeling programs.
6. A Crappie Recruitment Model is needed to determine what variables are
greatest impact on crappie recruitment in Arkansas waters. The model would
potentially help fishery managers identify those problems in reservoirs
corrective management could be applied, and would also help in predicting
year-classes and thus, supplemental stocking guidelines on an annual basis.
7. Fishery managers should explore the use of other sampling techniques such
larger 8’ x 8’ or 6’ x 6’ floating trap nets and spring/fall electrofishing
in lakes where
standard trap net gear has been ineffective at sampling the crappie
1. Trap net boats and motors ($6,000) replaced as needed
2. Trap nets ($475/net) replaced as needed
3. Dissecting Microscopes
4. Ocular micrometers
5. Data reduction and analysis software for trap nets (currently being
6. Exploitation/Tag Reward studies ($2,500/each)
7. Continuing Education workshops on population modeling
8. Develop standardized protocol for assessing habitat needs in Arkansas
Upper White Oak
1993 0.68 287 18.03 22.95 30.33 61.25
Lower White Oak
1993 0.06 265 0 16.67 1.92 33.75
1993 3.2 264 13.75 25.6 0.68 58.75
1994 9.3 260 12.4 26.5 0.65 62.5
TABLE 2. ARKANSAS CRAPPIE POPULATION ASSESSMENT
Number per Trap Net-Night (excluding YOY)
0-2 3-4 5-9 10-19 20-29 30-39 >40
Density 1 2 5 8 9 8 5
(good growth) 1 2 5 8 10 10 10
(poor growth) 1 2 3 4 4 3 2
Mean Length (mm) at Age 2+
151-175 176-200 201-225 226-250 251-275 >275
Growth Rate 1 4 8 10 8 6
(w/ good density) 2 6 9 10 10 10
Percent Age 3 and Older (excluding YOY)
<4.9 5-9.9 10-14.9 15-19.9 20-24.9 >25
Age Structure 1 4 8 10 8 6
good growth 2 5 9 10 10 8
Percent Over 250-mm (10”) (excluding YOY)
<10 10-19 20-29 30-39 40-49 50-59 >59
Size Structure 1 3 5 8 10 8 5
good density 1 3 7 10 10 10 8
Number of Age 0 per Trap Net-Night
<1.0 1.0-1.9 2.0-3.9 4.0-9.9 10-18.9 19-29.9 >29.9
Recruitment 1 4 6 8 9 8 4
good growth 1 4 6 10 10 10 6
good growth Mean Length At End of 3rd Growing Season (2+) >250mm.
poor growth Mean Length At End of 3rd Growing Season (2+) <201mm.
good density At Least 20 Age 1 and Older Per Trap Net-Night.
To Calculate Total Assessment Value (Maximum 100) sum:
Value for Number per Trap Net-Night X 1.25 =
Value for Mean Length At Age (2+) X 2.50 =
Value for Percent Age 3 and Older X 2.50 =
Value for Percent Over 250 mm (10”) X 2.50 =
Value for Number of Age 0 per Trap Net-Night X 1.25 =
Total Assessment Value =
FIGURE 1. Management strategies for crappie populations under various
Mean Length @ Age 2+
<200mm 201-275mm >275mm
Crappie length limits
Decrease predator population
Relax predator creel limits
Relax crappie creel limits
Enhance predator populations
Impose predator creel limits
Control aquatic vegetation
% Fish > 250 mm
No change recommended
% Fish = 3+
Crappie length limit
Decrease predator population
Relax predator creel limits
# of Fish / Net Night > 1+
No change recommended
# of YOY / Net Night
% Fish = 3+
No change recommended
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