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North American Journal of Fisheries Management
ISSN: 0275-5947 (Print) 1548-8675 (Online) Journal homepage: http://www.tandfonline.com/loi/ujfm20
Fillet Weight and Fillet Yield: New Metrics for the
Management of Panfish and Other Consumption-
Oriented Recreational Fisheries
John Lyons, Andrew L. Rypel, Jonathan F. Hansen & David C. Rowe
To cite this article: John Lyons, Andrew L. Rypel, Jonathan F. Hansen & David C. Rowe (2017)
Fillet Weight and Fillet Yield: New Metrics for the Management of Panfish and Other Consumption-
Oriented Recreational Fisheries, North American Journal of Fisheries Management, 37:3, 550-557,
DOI: 10.1080/02755947.2017.1296514
To link to this article: http://dx.doi.org/10.1080/02755947.2017.1296514
Published online: 11 Apr 2017.
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MANAGEMENT BRIEF
Fillet Weight and Fillet Yield: New Metrics for the
Management of Panfish and Other Consumption-Oriented
Recreational Fisheries
John Lyons*and Andrew L. Rypel
Wisconsin Department of Natural Resources, 2801 Progress Road, Madison, Wisconsin 53718, USA
Jonathan F. Hansen
1
Wisconsin Department of Natural Resources, 101 South Webster Street, Madison, Wisconsin 53703, USA
David C. Rowe
Wisconsin Department of Natural Resources, 3911 Fish Hatchery Road, Fitchburg, Wisconsin 53711,
USA
Abstract
Proposals for regulations to improve panfish size structure
often lack angler support, in part because of a perceived loss of
panfish harvest. We propose that fillet weight and fillet yield, the
percentage of the body weight available as fillets, are useful
metrics for exploring regulation options and potential outcomes.
We determined fillet weight and fillet yield for 321 Bluegill
Lepomis macrochirus, 139 Black Crappie Pomoxis nigromacula-
tus, and 137 Yellow Perch Perca flavescens and developed equa-
tions to predict fillet weight from total length. Mean fillet yield
was 29.5% for Bluegills, 28.6% for Black Crappies, and 33.1%
for Yellow Perch. We used Bluegill size increases associated with
a reduction in daily bag limits from 25 fish to 10 fish in seven
Wisconsin lakes and then estimated fillet weights to compare the
potential total weight of Bluegill fillets available to anglers under
both a 10- and a 25-fish daily bag limit. We projected that many
anglers might obtain a greater weight of Bluegill fillets per fishing
trip under a 10-fish bag limit. We conclude that for consumption-
oriented fisheries, fillet weight and fillet yield have value in
demonstrating how more restrictive harvest regulations may
sometimes lead to a greater weight of fillets for most anglers.
A key goal in the management of consumption-oriented
recreational fisheries is to provide anglers with adequate num-
bers of fish of harvestable size. But where angling effort is
relatively high, this goal may be difficult to achieve. This is
exemplified by the group of species known as “panfish,”often
defined as rock basses Ambloplites spp., sunfishes Lepomis
spp., crappies Pomoxis spp., and Yellow Perch Perca flaves-
cens, which supports some of the most popular freshwater
sport fisheries in North America (USFWS and USCB 2014).
Many heavily fished panfish populations lack the large indivi-
duals that anglers prefer, detracting from their popularity and
posing a challenge to their management (Beard et al. 1997;
Coble 1988).
Panfish are widespread, common, and heavily fished in
much of North America (USFWS and USCB 2014).
Historically, the ubiquity and ease of capture of panfish has
been taken as evidence that panfish populations are relatively
immune to growth overfishing, and consequently angling har-
vest limits have typically been quite liberal, in many instances
with no size limits, no closed seasons, and unlimited or high
daily bag limits (Quinn and Paukert 2009; Rypel et al. 2016).
However, because angling harvest tends to focus on the largest
individuals, liberal regulations have often led to undesirable
size structure, with abundant small fish but few of the larger
“keepers”that most anglers prefer (Coble 1988; Beard et al.
1997; Miranda and Dorr 2000; Isermann et al. 2005; Rypel
et al. 2016). In response, more restrictive regulations have
been proposed to improve the abundance of larger panfish
(Allen and Miranda 1995; Beard et al. 1997;Jacobson 2005;
*Corresponding author: john.lyons@wisconsin.gov
1
Present address: Minnesota Department of Natural Resources, 1200 Warner Road, St. Paul, Minnesota 55106, USA.
Received April 19, 2016; accepted February 10, 2017
550
North American Journal of Fisheries Management 37:550–557, 2017
© American Fisheries Society 2017
ISSN: 0275-5947 print / 1548-8675 online
DOI: 10.1080/02755947.2017.1296514
Edison et al. 2006; Mosel et al. 2015; Rypel 2015). Under
some conditions, harvest restrictions may lead to increases in
total fishery yield as gains in the size of fish harvested offset
reductions in the number of fish kept (Colvin 1991; Webb and
Ott 1991; Allen and Miranda 1995; Isermann et al. 2007).
However, despite evidence to the contrary, many anglers per-
ceive that restrictive regulations will reduce the amount of fish
that can be kept for food, and consequently proposals to
reduce panfish harvest are often unpopular (Reed and
Parsons 1999; Paukert et al. 2002; Edison et al. 2006). Yet,
at the same time, panfish anglers often express a willingness to
keep fewer fish if those fish are larger, which is usually the
ultimate goal of more restrictive regulations (Hale et al. 1999;
Reed and Parsons 1999; Paukert et al. 2002; Isermann et al.
2005; Petering et al. 1995). This apparent contradiction in
panfish angler attitudes suggests that many anglers do not
fully understand the purpose of more restrictive regulations
and that new ways of explaining fishery management goals
and expected outcomes are needed to improve support for the
acceptance of regulation changes (e.g., Petering et al. 1995).
We believe one reason anglers may not fully understand or
support more restrictive harvest regulations is the lack of an
easily applied measure to assess and explain the trade-offs
between the harvests of greater numbers of smaller fish versus
fewer larger fish. Anglers and fisheries managers frequently
communicate about the quality of a fish population by dis-
cussing the size of the fish caught. However, it remains
unclear the extent to which the size of harvested fish relates
to the amount of consumable food. Fisheries managers some-
times use total fishery yield, the estimated sum of the weights
of all harvested fish, to compare the effects of various regula-
tions. However, total yield for a fishery is not a direct measure
of the amount of food an individual angler will likely be able
to bring home and ultimately consume. We propose that the
weight of edible fillets available to anglers from fish of parti-
cular sizes would be a better metric for helping anglers under-
stand the pros and cons of different regulation options.
Our objective in this paper was to provide quantitative data
on the relationship between fish size and the amount of edible
fillets for three common panfish species. We estimated fillet
weight from size (total length) for three popular panfish spe-
cies, Bluegill Lepomis macrochirus, Black Crappie Pomoxis
nigromaculatus, and Yellow Perch, and we also calculated the
percentage of the body weight that is available as boneless
fillets, termed fillet yield. From these we used creel and fishery
survey data for Bluegills from Wisconsin lakes as an example
of how fillet weight and fillet yield might be used to explore
and communicate to anglers the potential effects of more
restrictive harvest regulations.
METHODS
We solicited fillet weight data from current or former
Wisconsin Department of Natural Resources (WDNR)
employees (including ourselves) who were willing to partici-
pate voluntarily during their nonwork personal angling activ-
ities. We asked each participating angler to provide
information on the capture location, date, sex, species, total
length (TL), total weight, and weight of the boneless skinless
fillets for any Bluegills, Black Crappies, or Yellow Perch kept
for eating. We provided precision weighing scales to partici-
pants and gave general guidelines on how to prepare fillets—
remove skin, exclude ribs and other conspicuous bones, and
include abdominal (“belly”)flesh, without spending atypical
amounts of time or effort in filleting the fish—and encouraged
participants to include as wide a size range of fish and as many
different fishing trips as possible.
Fillet weight data were summarized by species, and fillet
yield was calculated by dividing fillet weight by fish weight
and expressing the quotient as a percentage. We compared
fillet yield among species using ANCOVA with TL as the
covariate and least-squares means multiple comparisons
tests. We estimated fillet weight from fish TL for each species
using a linear regression having the following form: log
10
(fillet weight) = B
0
+B
1
× log
10
(TL), where B
0
and B
1
are
estimated coefficients (Neumann et al. 2012), fillet weight is
measured in grams, and TL is measured in millimeters. All
statistical analyses were done in SAS (version 9.3; Cary, North
Carolina) and were considered significant if P< 0.05.
We developed an example to illustrate how fillet weights
and fillet yields might be used in assessing and communicating
the projected results of angling regulations. First, we devel-
oped tables of the weights of fillets that could be produced
from Bluegills, Black Crappies, and Yellow Perch of different
TLs. Second, we employed creel survey data on the distribu-
tions of daily bags and TLs of harvested Bluegills to explore
how the weight of Bluegill fillets from a fishing trip might
vary depending on how many fish were kept. We had available
single-year creel surveys from 34 Wisconsin lakes during
1998–2014 that provided data from a total of 6,401 anglers,
2,156 of whom harvested a total of 10,798 Bluegills (WDNR,
unpublished data). We used these creel data to estimate the
weight of fillets an angler would obtain from realistic combi-
nations (observed means, medians, minima, and maxima) of
sizes and numbers of Bluegills. We also estimated how many
Bluegills of a particular size an angler would need to keep for
227 g (0.5 lb) of fillets, which Wisconsin has used as a bench-
mark in presentations to anglers on panfish harvest regulations
(WDNR 2015). Finally, we used observed data on changes in
Bluegill TL in response to experimental reductions in daily
bag limits from 25 fish to 10 in seven Wisconsin lakes (Rypel
2015), none of which had creel surveys, to illustrate how
amounts of fillets available to anglers per individual Bluegill
might change in response to more restrictive panfish harvest
limits. Across all seven lakes, Bluegill TL increased by a
mean of 21 mm following the bag limit reductions, with TL
changes in individual lakes ranging from −5 mm to 64 mm.
We assumed that the mean size of Bluegills harvested by
MANAGEMENT BRIEF 551
anglers prior to the bag limit reduction was the same as the
mean value from the 34 creel surveys of the 25-bag-limit lakes
and that the change in mean TL of Bluegills in electrofishing
or fyke-net assessments of the seven lakes was also reflected
in the change in the mean TL of the Bluegills kept by anglers.
RESULTS
We obtained fillet weight data from 321 Bluegills, 139
Black Crappies, and 137 Yellow Perch. These data were
collected by 28 anglers (including ourselves) over a 13-
month interval (40 dates from December 21, 2013, to
January 16, 2015) from 25 discrete locations on Wisconsin’s
lakes and rivers. However, none of the species were collected
from all locations or by all anglers (Table 1). Bluegills had the
widest and most balanced coverage in terms of numbers of
locations and anglers.
For all three species, fillet weight was strongly and signifi-
cantly positively related to TL (Figure 1;Tables 2,3). At any
given TL, Bluegills had the highest fillet weight and Yellow
Perch the lowest. Mean fillet yield ranged from 28.6% for
Black Crappies to 29.5% for Bluegills to 33.1% for Yellow
Perch (Table 4). Black Crappie and Bluegill fillet yields were
statistically indistinguishable but significantly lower than that
of Yellow Perch (F= 6.12, P= 0.0023). Although standard
deviations for mean species fillet yields were not particularly
high, ranging from 4.4% to 5.3%, the fillet yield of individual
fish varied considerably, with minimum and maximum values
differing by 34.6% for Bluegills, 27.8% for Black Crappies,
and 20.8% for Yellow Perch. Black Crappies had a small but
significant negative correlation between fillet yield and TL,
whereas Bluegills and Yellow Perch had no significant corre-
lations (Figure 1). In other words, larger Black Crappies had a
slightly lower fillet yield than smaller Black Crappies, but the
fillet yield of Bluegills and Yellow Perch remained constant
across different sizes.
Creel survey data from 34 Wisconsin lakes with a 25-fish
daily bag limit indicated that for anglers who had kept at least
one Bluegill, the median daily harvest per angler was 2.4 (i.e.,
50% of anglers kept three or more Bluegills and 50% kept
only one or two), the mean was 5.0 (29% of anglers kept more
than five), and the maximum was 25, the legal upper limit
(Figure 2). Less than 1% of anglers kept the limit of 25, and
16% kept 10 Bluegills or more. The mean TL of Bluegills kept
by anglers was 173 mm. Using this mean length, the fillet
weight of a single Bluegill was 30.7 g and the total fillet
weights of the median, mean, 10-bag, and maximum (25-
bag) angler harvests were 73.7 g, 153.5 g, 307.0 g, and
767.5 g, respectively. It would require 7.4 Bluegills of the
mean TL to achieve the benchmark of 227 g of fillets
(Table 5).
Based on the results from Rypel (2015), the projected mean
TL of Bluegills in the angler harvest after the bag limit
reduction would be 194 mm, with a range of 168 to
237 mm. From these lengths, the estimated mean weight of
fillets from an individual Bluegill would be 43.8 g, with a
range of 27.3 to 84.5 g. Based on these values, many combi-
nations of Bluegill size and number kept would result in a
higher total weight of fillets for the majority of individual
anglers than they would obtain under the 25-fish bag limit
(Table 5). Indeed, for the maximum projected increase in
Bluegill TL, 64 mm, an angler who kept a “limit”of 10 fish
from a 10-fish-bag-limit lake would have a higher weight of
fillets than would an angler who kept a limit of 25 fish from an
average 25-fish-bag-limit lake.
DISCUSSION
Our study appears to be the first to present data on fish fillet
weight and its relationship to TL and then to use these fillet
weights to assess different fishing regulations. Fillet yield is a
metric commonly used in aquaculture and can be employed to
approximate fillet weight if total fish weight is known, but only a
few estimates of fillet yield for Yellow Perch and no estimates for
Bluegills or Black Crappies are available in the literature.
Rosauer et al. (2011) reported fillet yields of 34.6–35.2%, higher
than our value of 33.1%, for captive stocks of Yellow Perch. A
higher fillet yield than ours, 34.9%, for Yellow Perch from
Stilwell Reservoir, New York has also been reported (M.
Dexter, K. Van Alstine, M. Courtney, and Y. Courtney, U.S. Air
Force Academy, unpublished). Fillet yields for the closely related
Eurasian Perch Perca fluviatilis were even greater, ranging from
40.1% to 47.9% (Jankowska et al. 2007;Mairesseetal.2007).
Discrepancies in the estimates of fillet yield across studies could
reflect differences in fish condition among populations, variation
in filleting procedures, or both.
Our application of the fillet weight and fillet yield data to
an experimental bag limit reduction in seven Wisconsin lakes
suggested that despite a substantial drop in the Bluegill bag
limit, from 25 fish to 10, there were a variety of realistic
TABLE 1. Description of the numbers of fish and sources of data used in the fillet weight analyses.
Species and total Individuals Locations Dates Anglers TL range (mm)
Bluegill 321 21 33 16 106–245
Black Crappie 139 9 12 12 147–330
Yellow Perch 137 7 7 8 118–285
Totals 597 25 40 27 106–330
552 LYONS ET AL.
scenarios under the new regulation in which many, if not most,
anglers would be able to bring home a similar or even greater
weight of Bluegill fillets. This finding was used to help con-
vince Wisconsin anglers to endorse an expansion of the
experimental reduced panfish bag limits to 94 additional
lakes in 2016 (WDNR 2016).
Bluegill bag limit reductions can increase the total
weight of fillets available to most anglers if they lead to
an increase in mean Bluegill size, which is supported by
evaluations in Minnesota (Jacobson 2005) and Wisconsin
lakes (Rypel 2015). However, these two studies indicate that
size increases may take several years to manifest themselves
FIGURE 1. Relationship of fish TL to fillet weight (top panels) and fillet yield (bottom panels) for Bluegills, Black Crappies, and Yellow Perch. Statistically
significant regression lines are shown.
MANAGEMENT BRIEF 553
and seem most likely to occur in relatively productive lakes,
where angler harvest is high and larger fish are removed
before they reach their potential maximum size. In low-
productivity or low-harvest lakes, a size increase may not
occur despite a reduced bag limit. The major unknown in
any future projection of regulation effects is if and how big
of a size increase will occur, and the conclusion of whether
or not the reduced bag limit will be beneficial to the har-
vest-oriented angler hinges on the magnitude of this
increase. Like all projections into the future, a variety of
assumptions had to be made about how the Bluegill popula-
tion would change and how angler harvest would respond,
and the predicted responses we present represent several
plausible but certainly not guaranteed outcomes.
The fillet weight and fillet yield of any species at any given
size will likely be highly variable because of the often large
differences in fish condition across space and time (Neumann
et al. 2012) and the wide range of filleting techniques and
abilities among anglers. Consequently, applications of fillet
weight data to regulation assessments must be tempered by
high uncertainty in the estimates of the weight of fillets avail-
able in the harvest. Thus, any equations relating fillet weights
to TL and any estimates of fillet yields should be treated as
rough approximations rather than precise determinations both
in fisheries analyses and in discussions with anglers.
MANAGEMENT IMPLICATIONS
Our Bluegill example illustrates how fillet weight can be
used to translate the potential effects of fishing regulations into
a currency of direct interest to anglers. Calculations from the
equations in Table 2 or data from Table 3 or 4 allow further
exploration of how potential changes in Bluegill, Black
Crappie, or Yellow Perch TL or weight in response to more
stringent regulations might change the weight of fillets an
angler could obtain from a fishing trip. As a hypothetical
example, if a reduced daily bag limit from 15 to 10 panfish
TABLE 2. Coefficients and statistics for the relationship between TL and
fillet weight for the three species, using the following linear regression
equation: log
10
(fillet weight) = B
0
+B
1
× log
10
(TL), where weight is mea-
sured in grams and TL is measured in millimeters.
Regression coefficients Regression statistics
Species B
0
B
1
FP
Bluegill –5.862 3.280 1,567.89 <0.0001
Black Crappie –6.312 3.418 2,344.94 <0.0001
Yellow Perch –5.810 3.163 1,603.98 <0.0001
TABLE 3. Fillet weights at specific TLs for Bluegills, Black Crappies, and Yellow Perch, estimated from equations in Table 2. Abbreviations are as follows:
FW= fillet weight, NA = not applicable (indicates fillet weights that were not estimated for TL because they were more than 5 mm outside of the range of TLs
included in the development of the equations), and N= the number of fish required to produce 227 g (0.5 lb) of fillets, a standard Wisconsin benchmark (WDNR
2016).
Bluegill Black Crappie Yellow Perch
TL(mm) TL (in) FW (g) FW (lb) NFW (g) FW (lb) NFW (g) FW (lb) N
102 4.0 5.3 0.01 42.8 NA NA NA NA NA NA
114 4.5 7.7 0.02 29.5 NA NA NA 5.0 0.01 45.4
127 5.0 10.9 0.02 20.8 NA NA NA 7.0 0.02 32.4
140 5.5 15.0 0.03 15.1 NA NA NA 9.5 0.02 23.9
152 6.0 19.7 0.04 11.5 14.0 0.03 16.2 12.3 0.03 18.5
165 6.5 25.8 0.06 8.8 18.5 0.04 12.3 16.0 0.04 14.2
178 7.0 33.1 0.07 6.9 24.0 0.05 9.5 20.3 0.04 11.2
191 7.5 41.7 0.09 5.4 30.5 0.07 7.4 25.4 0.06 8.9
203 8.0 50.9 0.11 4.5 37.6 0.08 6.0 30.8 0.07 7.4
216 8.5 62.4 0.14 3.6 46.5 0.10 4.9 37.5 0.08 6.1
229 9.0 75.6 0.17 3.0 56.7 0.12 4.0 45.1 0.10 5.0
241 9.5 89.3 0.20 2.5 67.6 0.15 3.5 53.0 0.12 4.3
254 10.0 NA NA NA 80.9 0.18 2.8 62.6 0.14 3.6
267 10.5 NA NA NA 95.9 0.21 2.4 73.3 0.16 3.1
279 11.0 NA NA NA 111.4 0.25 2.0 84.2 0.19 2.7
292 11.5 NA NA NA 130.2 0.29 1.7 NA NA NA
305 12.0 NA NA NA 151.1 0.33 1.5 NA NA NA
318 12.5 NA NA NA 174.3 0.38 1.3 NA NA NA
330 13.0 NA NA NA 197.8 0.44 1.1 NA NA NA
554 LYONS ET AL.
was projected to increase mean Black Crappie TL in the creel
from 203 to 229 mm, then the mean weight of a fillet would be
expected to increase 19.1 g (50%), from 37.6 to 56.7 g, and
the number of fish needed to meet the 227-g-of-fillets bench-
mark would be expected to decline by two fish (33%), from
six to four. An angler who kept his or her limit would be
expected to take home approximately the same weight of
fillets (564 g versus 567 g) under both regulations. If this
same bag limit reduction was projected to increase Yellow
Perch TL in the creel from 152 to 165 mm, then the mean
weight of fillets would be expected to increase 3.7 g (30%),
from 12.3 to 16.0 g, and the number of fish needed to meet the
227-g benchmark would be expected to decline by 4.3 fish
(23%), from 18.5 to 14.2. An angler who kept his or her limit
would be expected to take home a greater weight of fillets
(185 g) under the 15-fish limit than under the 10-fish limit
(160 g). Whether anglers would decide that this hypothetical
bag limit change was acceptable would undoubtedly depend
on many other factors besides just the projected increases in
individual fillet weights, but they would have a better idea of
how the amount of food they might be able to bring home was
likely to change under the new regulation.
Although the mean weight of panfish fillets and the total
fishery yield are likely correlated, our experiences in
discussing panfish regulations with the public lead us to
believe that the fillet weight and fillet yield of individual
panfish are more meaningful metrics to individual anglers
than is total fishery yield. Fillet yield and fillet weight data
(Tables 3,4) can provide anglers with estimates of how much
food they might obtain from a single panfish or from a panfish
fishing trip under different fishery regulation scenarios. They
can clearly illustrate how a restrictive regulation might result
in fewer fish in the creel but similar amounts of or even more
food on the table. Providing an easy-to-understand and rele-
vant benchmark, such as the number of fish necessary for a
certain weight of fillets, allows anglers to make direct and
informed comparisons among various regulation options that
might be proposed to change the size, catch rate, or both of
fish, such as the reduced bag limit in our Bluegill example. We
provide data for three panfish species, but throughout North
America at least 100 freshwater fish species have regulated
sport fisheries with angler harvest, so studies of additional
species are certainly warranted. Fillet weight and fillet yield
have potential utility for any species that is part of a consump-
tion-oriented recreational fishery.
Although we believe that fillet weight and fillet yield are
more meaningful to anglers than fishery yield, we certainly do
not mean to suggest that fillet weight or fillet yield should
replace calculations of fishery yield or other relevant fishery
statistics, such as population density, size structure, propor-
tional stock density, or relative weight. Fishery yield and other
fishery statistics remain essential to any complete assessment
of angling regulations or other fishery management activities,
and without them any analysis of potential regulation changes
will remain unacceptably speculative (Beard et al. 1997;
Isermann et al. 2007; Mosel et al. 2015). Fillet weight and
fillet yield build upon rather than substitute for traditional
fishery measures, providing a new communication tool for
translating essential technical results and predictions from
fisheries models into a simple format of strong direct interest
to the angler. Fishery yield and fillet weight–fillet yield are
complimentary and should be used in concert: fishery yield
will provide insight into how a population might change in
response to a regulation and fillet weight and fillet yield will
provide insight into what that change might mean for anglers.
Given the inherently and unavoidably high variation in
fillet weight and fillet yield, presentations of fillet weight or
fillet yield information associated with a potential angling
regulation change should always be accompanied by the
caveat that these are estimated values for the “average”angler,
who does not really exist, and that the actual weight of fillets
that a particular angler is likely to bring home will depend on
his or her level of fishing skill and filleting ability. In con-
sidering different harvest regulation alternatives, managers
should only present differences in the total weight of fillets
available to the angler when these differences are relatively
large and of a magnitude that an angler would clearly notice
on the filleting board.
TABLE 4. Summary statistics for fillet yield for Bluegills, Black Crappies,
and Yellow Perch.
Fillet yield (%)
Species Mean SD Minimum Maximum
Bluegill 29.5 5.0 11.8 46.4
Black Crappie 28.6 5.3 14.3 42.1
Yellow Perch 33.1 4.4 22.4 43.2
FIGURE 2. Plot of the distribution of harvested Bluegills in the daily bags of
individual anglers from annual creel surveys of 34 Wisconsin lakes that had a
daily bag limit of 25 fish.
MANAGEMENT BRIEF 555
ACKNOWLEDGMENTS
We thank the current and former WDNR staff who provided
data: Jim Amrhein, Scott Braden, Tom Cichosz, Jody Derks, Wes
Ellarson, Steve Gilbert, Jen Hauxwell, Joe Hennessey, Elliot
Hoffman, Paul Kanehl, Ryan Koenigs, John Komassa, Kim
Kuber, Al Niebur, Randal Piette, Jonathan Pyatskowit, Mike
Rennicke, Greg Sass, Mike Staggs, Gene Van Dyck, Dan
Walchak, Kurt Welke, Max Wolter, and Ryan Zernzack. We also
thank Paul Rasmussen for statistical advice and assistance. Support
for data analysis and manuscript preparation was provided in part
by the Federal Aid in Sport Fish Restoration, Project F-95-P.
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TABLE 5. Estimated weights of Bluegill fillets available to anglers under a daily bag limit of 25 fish versus potential weights available under a limit of 10 fish.
The current daily bag limit scenario is based on creel survey data from 34 lakes; 2.4 fish is the median number harvested per angler and 5.0 is the mean. Under
the 10-fish daily bag limit scenario, possible changes in mean TL are based on the range of responses observed in an evaluation of reduced daily bag limits on
seven Wisconsin lakes (Rypel 2015). Abbreviations are as follows: NA = not applicable (as no more than 10 fish could be legally kept) and N= the number of
fish needed for 227 g (0.5 lb) of fillets.
Total fillet weight (g) per individual angler harvest
Mean TL (mm)
of harvested fish Change in TL
1.0
fish
2.4
fish
5.0
fish
10
fish
25
fish N
Current daily bag limit (25)
173 30.7 70.6 153.5 307.0 767.5 7.4
Reduced daily bag limit (10)
168 Smallest (–5 mm) 27.3 62.8 114.7 273.0 NA 8.3
194 Mean (21 mm) 43.8 100.7 184.0 438.0 NA 5.2
237 Largest (64 mm) 84.5 194.4 354.9 845.0 NA 2.7
556 LYONS ET AL.
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