LOUISIANA DEPARTMENT OF
WILDLIFE & FISHERIES
OFFICE OF FISHERIES
INLAND FISHERIES DIVISION
PART VI -B
WATERBODY MANAGEMENT PLAN SERIES
Larto-Saline Complex
WATERBODY EVALUATION &
RECOMMENDATIONS
2
CHRONOLOGY
March 18, 2010 - Prepared by
Richard D Moses, Biologist Manager, District 3
Richard McGuffee, Biologist Supervisor, District 3
December 1, 2014 – Updated by
Richard Moses, Biologist Manager, District 3
Shelby Richard, Biologist II, District 3
March 2018 – Revised by
Richard McGuffee, Biologist Manager, District 3
Shelby Richard, Biologist Supervisor, District 3
The remainder of the page intentionally left blank.
3
TABLE OF CONTENTS
WATERBODY EVALUATION ................................................................................................................................. 4
STRATEGY STATEMENT ................................................................................................................................... 4
Recreational........................................................................................................................................................... 4
Commercial ........................................................................................................................................................... 4
Species of Greatest Conservation Need ................................................................................................................. 4
EXISTING HARVEST REGULATIONS ............................................................................................................. 4
Recreational........................................................................................................................................................... 4
Commercial ........................................................................................................................................................... 4
SPECIES EVALUATION ....................................................................................................................................... 4
Recreational........................................................................................................................................................... 4
Commercial ......................................................................................................................................................... 16
Creel Survey ........................................................................................................................................................ 17
HABITAT EVALUATION ................................................................................................................................... 21
Substrate .............................................................................................................................................................. 22
Artificial Structure ............................................................................................................................................... 22
CONDITION IMBALANCE / PROBLEM ......................................................................................................... 22
CORRECTIVE ACTION NEEDED .................................................................................................................... 22
RECOMMENDATIONS .......................................................................................................................................... 23
APPENDIX I .............................................................................................................................................................. 24
APPENDIX II ............................................................................................................................................................ 28
4
WATERBODY EVALUATION
STRATEGY STATEMENT
Recreational
Sportfish species, primarily Largemouth Bass (LMB, Micropterus salmoides) and crappie
(Pomoxis spp.), are managed to provide a sustainable population while providing anglers the
opportunity to catch or harvest adequate numbers of fish to maintain angler interest and efforts.
Commercial
Commercial fishing is minimal in the Larto-Saline Complex. Water control measures over the
past 40 years have altered water flow patterns and fisheries habitat in such a manner that the
Larto-Saline Complex does not support high numbers of commercial species. A strategy
directed specifically to the commercial fishery is not applied.
Species of Greatest Conservation Need
No threatened or endangered fish species are known to inhabit this waterbody.
EXISTING HARVEST REGULATIONS
Recreational
This waterbody is managed under statewide regulations for all fish species. The Louisiana
Department of Wildlife and Fisheries recreational fishing regulations may be viewed at the
link below:
http://www.wlf.louisiana.gov/regulations
Commercial
The LDWF commercial fishing regulations may be viewed at the link below:
http://www.wlf.louisiana.gov/regulations
SPECIES EVALUATION
Recreational
Largemouth Bass
Largemouth Bass (LMB) populations are targeted for assessment because they are a species
indicative of the overall health of the fish population due to their high position in the food
chain, and they are a popular recreational species. Electrofishing is the most efficient sampling
method for collecting Largemouth Bass to evaluate abundance and size distribution.
Largemouth Bass Relative Abundance and Size Structure Indices
Electrofishing has been used to collect Largemouth Bass population data in the Larto-Saline
Complex since the fall of 1989. Catch-per-unit-effort (CPUE) from spring and fall
electrofishing are used as indicators of LMB relative abundance. Spring electrofishing results
5
0
25
50
75
100
125
1992 2000 2001 2006 2009
Number Per Hour
show a relatively stable average CPUE for the sampling period 1992 through 2009 (Figure 1).
The significant increase in CPUE observed in 2000 can likely be attributed to a drought that
caused low water levels at the time of sampling. Low water levels force LMB to congregate
in areas accessible to electrofishing methods. Fall electrofishing from 1989 through 2010 also
indicated a relatively stable CPUE average (Figure 2). Fall samples from 2015-2017 had a
significant increase in CPUE. These observed variations are likely due to increased spawning
and nursery habitat from the 2014 drawdown and high water events. Significant variable
annual recruitment is typical for sub-stock catch rates. Sub-stock (<8”) and stock-size (8-12”)
LMB CPUE from fall 2015, 2016, and 2017 indicates that the 2014 drawdown and high water
increased spawning success and recruitment in those years (Figures 3 and 4).
Figure 1. Average CPUE (± SE) for Largemouth Bass collected during spring electrofishing
from Larto-Saline Complex, Louisiana, from 1992 – 2009.
6
0
25
50
75
100
125
150
175
200
225
250
Number Per Hour
YEAR
Figure 2. Average CPUE (± SE) for Largemouth Bass collected during fall electrofishing
from Larto-Saline Complex, Louisiana from 1989-2017.
Figure 3. The average CPUE for Largemouth Bass by size class collected from Larto-Saline
Complex, Louisiana during spring electrofishing from 1992 – 2009.
0
25
50
75
100
125
1992 2000 2001 2006 2009
Number Per Hour
YEAR
Sub-Stock (<8") Stock (8"-12") Quality (12"-15")
Preferred (15"-20") Memorable and Greater (>20")
7
Figure 4. The average CPUE for Largemouth Bass by size class collected from Larto-Saline
Complex, Louisiana, during fall electrofishing from 1989 – 2017.
Proportional stock density (PSD) and relative stock density (RSD) are indices used to
numerically describe length-frequency data (Figures 5 and 6). Proportional stock density
compares the number of fish of quality size or greater (greater than 12 inches for Largemouth
Bass) to the number of bass of stock size or greater (8 inches in length). PSD is expressed as a
percent. A fish population with a high PSD consists mainly of larger individuals, whereas a
population with a low PSD consists mainly of smaller fish. For example, Figure 5 below
indicates a PSD of 41 for 2006. The number indicates that 41% of the bass stock (fish over 8
inches) in the sample was at least 12 inches or longer. Individual lakes vary widely in their
ability to support populations of bass. PSD values between 40 and 60 are considered to be
satisfactory.
Number of bass>12 inches
PSD = ———————————— x100
Number of bass>8 inches
Relative stock density of preferred size (RSD
-p
) is the proportion of Largemouth Bass in a
stock (fish over 8 inches) that are 15 inches or longer.
Number of bass>15 inches
RSD
-p
= ———————————— x100
Number of bass>8 inches
0
25
50
75
100
125
150
175
200
225
250
1989 1990 1991 1992 1999 2000 2001 2003 2006 2010 2015 2016 2017
Number Per Hour
YEAR
Sub-Stock (<8") Stock (8"-12") Quality (12"-15")
Preferred (15"-20") Memorable and Greater (>20")
8
Figure 5. PSD and RSD-p for Largemouth Bass collected from Larto-Saline Complex,
Louisiana during spring electrofishing from 1992 – 2009.
Trends in sampling data indicate PSD and RSD
-p
values have increased from 1992 through
2009. This is likely the result of an increased level of complex cover during that time. Hydrilla
became established in the lake in the early 2000’s. Hydrilla coverage fluctuates depending on
the influence of water level fluctuation. PSD and RSD
-p
values based on fall electrofishing
results have gradually declined from all-time highs in 2010 (71 and 35%, respectively), to 40%
and 10%, respectively in 2017 (Figure 6). The 2017 values show a balanced Largemouth Bass
population.
0
10
20
30
40
50
60
70
1992 2000 2001 2006 2009
Percentage
Year
PSD RSD
9
Figure 6. PSD and RSD-p for Largemouth Bass collected from Larto-Saline Complex,
Louisiana during fall electrofishing from 1989 – 2017.
Forage
Abundances of shad and sunfishes are the primary forage of Largemouth Bass in the Larto-
Saline Complex. Crawfish are plentiful as well due to the regular occurrence of backwater
flooding. Forage availability is measured by shoreline seine sampling (Figure 7) and by
electrofishing sampling (Figure 8).
Forage availability is also measured indirectly through measurement of LMB body condition
or relative weight. Relative weight (Wr) is the ratio of a fish’s weight to the weight of a
“standard” fish of the same length. The index is calculated by dividing the weight of a fish by
the standard weight for its length, and multiplying the quotient by 100. Largemouth Bass
relative weights below 80 indicate a potential problem with forage availability. Information
displayed in Figure 9 suggests the presence of sufficient forage each year. Relative weight
values ranged from 83 to 108 from 1989-2017.
0
10
20
30
40
50
60
70
80
1989 1990 1991 1992 1999 2000 2001 2003 2006 2010 2015 2016 2017
Percentage
Year
PSD RSD
10
Figure 7. The CPUE (average number of fish per seine haul) of all species collected from
shoreline seining for Larto-Saline Complex, LA, from 1990 – 2019.
Figure 8. Number per hour of Lepomis spp., Dorosoma spp., and all other species less than 6
inches TL captured in standardized fall community samples on Larto-Saline Complex, LA,
from 2003-2017.
0
100
200
300
400
500
1990 2000 2001 2006 2009 2019
Average Number of Fish Per Haul
0
50
100
150
200
250
2003 2006 2017
Number of Individuals
Lepomis spp. Dorosoma spp. All Other Species
11
Figure 9. Relative weight values for stock-, quality-, and preferred-size classes of
Largemouth Bass collected during fall electrofishing for Larto-Saline Complex, Louisiana
from 1989 – 2017.
Largemouth Bass Age and Growth
Age and growth data was collected in 1989-1990, 2006, and 2015-2017. A population
assessment was conducted in 2015-2017 on Largemouth Bass in the Larto-Saline Complex.
The age, growth, and mortality results showed that the length-at-age is similar to the statewide
average until age 8, and within the 95% confidence interval (Figure 10). Ages 8-9 are below
the statewide average, but this is likely due to small sample sizes of that age class. Larto-Saline
Complex LMB growth rates are compared in Table 1. The maximum LMB length observed in
the most recent (2015-2017) Larto-Saline Complex assessment was 20 inches TL and the
maximum age recorded was 9 years.
0
25
50
75
100
125
1989 1990 1991 1992 1999 2000 2001 2003 2006 2010 2015 2016 2017
Relative Weight
Stock Quality Preferred
12
Table 1. Mean length at capture by age for Largemouth Bass in 1989-90, 2006, and 2015-17
for Larto-Saline Complex, Louisiana.
AGE
1989-1990
(N=87)
2006
(N=99)
2015
(N=168)
2016
(N=134)
2017
(N=136)
0
-
6.7
6.7
6.1
6.6
1
10.1
11.5
9.9
9.3
9.1
2
12.7
14.3
13.0
14.0
13.0
3
15.5
16.0
15.8
16.5
15.9
4
-
16.4
16.5
18.0
16.8
5
-
17.5
18.2
17.6
17.4
6
-
20.2
18.6
18.3
18.2
7
-
-
19.3
-
-
8
-
-
18.4
20.2
-
9
-
-
18.4
-
-
Figure 10. Mean length-at-capture by age class for Largemouth Bass collected during fall
electrofishing samples for the years 2015-2017 from Larto-Saline Complex, LA (n=437).
Error bars represent 95% confidence intervals.
0
5
10
15
20
25
0 1 2 3 4 5 6 7 8 9
Inches
Age Class
Statewide Average 2009-2017 Larto-Saline 2015-2017
13
Largemouth Bass Genetics
Electrophoretic (Isozyme) analysis of liver tissue was used to determine the percent of the
Florida Largemouth Bass (FLMB) genome present in the Larto-Saline complex. Florida
Largemouth Bass were not introduced into the Larto-Saline Complex by LDWF until 2015.
Prior to stocking, analysis showed that the Larto-Saline Complex LMB population did contain
a 12.1% Florida X northern hybrids in 2006. The introduction of FLMB likely occurred during
a high water event, since FLMB have been stocked into the Red River and other Louisiana
waterbodies. The LDWF stocked approximately 250,339 FLMB into the complex from 2015-
2017, and 81,100 FLMB were stocked in 2020. See Table 2 for a complete summary of genetic
testing.
Table 2. Largemouth Bass genetic testing results from Larto-Saline Complex, Louisiana.
Year
% Northern
% Florida
% Hybrid
% Florida Influence
2006
87.9 (n=87)
0
12.1 (n=12)
12.1
2015
100 (n=170)
0
0
0
2016
99.3 (n=143)
0.7 (n=1)
0
0.7
2017
91.1 (n=124)
1.5 (n=2)
7.4 (n=10)
8.9
Crappie
Crappie fishing in the Larto-Saline Complex is considered to be outstanding. Both Black
Crappie (Pomoxis nigromaculatus) and White Crappie (P. annularis) occur in the complex.
The dynamic nature of crappie populations includes considerable variance over time. Levels
of angler satisfaction are typically proportional to crappie population trends, and therefore, also
tend to be cyclic.
Crappie were sampled with electrofishing gear from 1999-2010. The sample catch rate was
variable, ranging between 0 and 65 fish per hour average (Figures 11 and 12). The technique
of sampling crappie with lead nets has become a standardized sampling method for LDWF.
Lead nets were effectively used to sample the crappie population from 2009 – 2012 (Figure
13). These results show an equal abundance and size distribution in population between both
species of crappie (Table 3 and Figure 14).
A crappie population assessment study was conducted from 2010 – 2012. An additional
population assessment, which began in 2020, is in progress and will be completed in the Fall
of 2022. The 2010-2012 assessment indicated that crappie in the Larto-Saline Complex had
the second lowest growth rate when compared to eight other lakes that were sampled during
that same time period, and reached a preferred-size class (10-inch TL) in 2.95 years on average
(Appendix I, Table 3). Because the majority of the fish sampled for age and growth were
captured by lead nets, age 0+ crappies are represented minimally due to this gear’s size
selectivity. Crappie growth rate results can be found in Table 4.
14
Figure 11. Average CPUE for crappie collected during fall electrofishing from Larto-Saline
Complex, Louisiana, from 1989-2010.
Figure 12. Average CPUE for crappie collected during spring electrofishing from Larto-
Saline Complex, Louisiana, from 2000-2009.
0
10
20
30
40
50
60
70
1989 1990 1991 1999 2000 2001 2003 2006 2010
Average CPUE
White Crappie Black Crappie
0
5
10
15
20
25
30
2000 2001 2006 2009
Average CPUE
White Crappie Black Crappie
15
Figure 13. Average CPUE for crappie generated from standardized lead net results from
Larto-Saline Complex, Louisiana, from 2009-2020.
Figure 14. Black crappie (n=834) and White Crappie (n=806) size distributions (inch
groups) on Larto-Saline Lake, Louisiana, generated from standardized lead net results
2009-2012.
0
50
100
150
200
250
3 4 5 6 7 8 9 10 11 12 13 14 15
Number
White Crappie Black Crappie
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
2009 2010 2011 2012 2020
Average CPUE
White Crappie Black Crappie
16
Table 3. The contribution of black and White Crappies to total crappie catch by year for
Larto-Saline Complex, Louisiana, fall lead net surveys 2009-2012.
Year
Black Crappie
White Crappie
Total
2009
5 (7%)
69 (93%)
74
2010
61 (14%)
366 (86%)
427
2011
320 (70%)
135 (30%)
455
2012
448 (65%)
236 (35%)
684
Total
834 (51%)
806 (49%)
1640
Table 4. Length at capture by age by species of crappie captured in 2011-2012 for Larto-
Saline Complex, Louisiana.
Commercial
Large fish species that comprise a commercial fishery are not found in sufficient numbers to
support a viable commercial fishery in the Larto-Saline Lake complex. However, periodic
backwater flooding of the Black and Red Rivers creates habitat to support a wide variety of
commercial species. Commercial harvest of these species is allowed in accordance with
statewide regulations. Wire traps, jug lines, trotlines and rod and reel are used to catch
commercial fish. Standardized biomass sampling (rotenone) conducted in 1998 showed the
most abundant commercial fish to be Channel Catfish followed by Freshwater Drum. Gill net
sampling conducted in 2018 showed buffalo and catfish to be the most abundant commercial
species.
Age
2011 Black
Crappie
(N=48)
2012 Black
Crappie
(N=104)
2011 White
Crappie (N=57)
2012 White
Crappie (N=107)
0
-
-
-
-
1
8.7
6.9
6.7
7.1
2
8.0
8.9
10.4
10.7
3
9.5
10.2
11.4
12.3
4
10.4
11.4
-
12.8
5
-
-
13.0
-
6
-
-
12.8
-
17
Figure 15. Biomass sampling results for commercial species for Larto-Saline Complex,
Louisiana, in 1998.
Figure 16. The CPUE (pounds per net night per 100’ net) for all fish collected in gill nets from
the Larto-Saline Complex, Louisiana in 2018.
Creel Survey
Angler creel surveys were conducted on Larto-Saline Complex in 2000, 2001, and 2015. A
creel survey is also in progress in 2021 to gather data on recreational fishing efforts and
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
Total CPUE (Pounds/100' Net/Net Night)
Species
0
20
40
60
80
100
120
1998
Pounds per Acre
Fresh water drum
Big mouth Buffalo
Small mouth Buffalo
Flathead Catfish
Channel Catfish
Blue Catfish
18
harvest.
Largemouth Bass Anglers
Creel Survey results show that 505 LMB anglers were interviewed. Catch rates improved from
1.66 LMB caught per angler trip to 3.45 LMB caught per angler trip from 2000 to 2015. The
retention rates were between 48.87% and 68.1% (Table 5). Harvested sub-stock-sized LMB
decreased from 2000 to 2015, while quality-sized LMB increased in 2015 (Figure 16). The
most frequently harvested size groups were 11-13 inches TL (Figure 17).
Crappie Anglers
Crappie creel survey results show that 637 crappie anglers were interviewed. Crappie catch
per angler trip decreased in 2015 (Table 5). This decreased catch per angler can be attributed
to high water events that allowed crappie to move into heavily wooded and vegetated areas
that anglers could not reach. Harvested crappie size class results indicate a normal distribution
with an increase in harvested memorable size crappie in 2015 (Figure 18). Angler harvested
inch groups ranged from 8-10 inches TL (Figure 19).
Table 5. Largemouth Bass and crappie creel survey results from Larto-Saline Complex,
Louisiana, from 2000, 2001, and 2015.
Year
Total
Interviews
LMB
Anglers
Interviewed
LMB
Catch Per
Angler
Trip
LMB
Retention
Rate
Crappie
Anglers
Interviewed
Crappie
Catch Per
Angler
Trip
2000
382
191
1.66
68.10%
243
7.86
2001
274
84
2.97
48.87%
204
11.09
2015
374
230
3.45
59.09%
190
5.22
19
Figure 17. Number of Largemouth Bass harvested by size class from creel surveys
conducted in 2000, 2001, and 2015 on Larto-Saline Complex, Louisiana.
0
10
20
30
40
50
60
2000 2001 2015
Number
Sub-Stock (<8") Stock (8"-12") Quality (12"-15") Preferred (15"-20") Memorable (>20")
20
Figure 18. Size distribution (inch groups) of angler harvested Largemouth Bass from Larto-
Saline Complex, Louisiana, creel survey from 2000, 2001, 2015.
Figure 19. Crappie angler harvest percentage by size class from creel surveys conducted in
2000, 2001, and 2015 on Larto-Saline Complex, Louisiana.
0
10
20
30
40
50
60
70
80
8 9 10 11 12 13 14 15 16 17 18 19 20 21
Number
LMB 2000 LMB 2001 LMB 2015
0
10
20
30
40
50
60
2000 2001 2015
Percentage
Sub-Stock (<5") Stock (5"-8") Quality (8"-10") Preferred (10"-12") Memorable (>12")
21
Figure 20. Size distribution (inch groups) of angler harvested crappie from Larto-Saline
Complex, Louisiana, creels surveys conducted in 2000, 2001, 2015.
HABITAT EVALUATION
Aquatic Vegetation
A vegetation survey was conducted on June 25 2020. No submersed vegetation was
observed. Emergent vegetation consisted of alligator weed (Alternanthera philoxeroides)
and water primrose (Ludwigia peploides), and covered approximately 100 acres
combined. No American lotus (Nelumbo lutea) was observed, even though it is typically
present. The absence of submersed vegetation and American Lotus is likely due to the
consecutive and prolonged high waters during the past few years. Floating vegetation
consisted of giant salvinia (Salvinia molesta), common salvinia (Salvinia minima), and
water hyacinth (Eichhornia crassipes). There were approximately 600 acres of giant
salvinia and 200 acres of common salvinia present. Giant salvinia was mostly located in
the Shad Lake area and the backs of the many bayous and coves in the complex. There
were approximately 200 acres of common salvinia present, mainly located in the Shad
Lake area. There were approximately 100 acres of water hyacinth present.
Vegetation projections in 2021 will depend on water levels and freezing weather events.
Submersed vegetation and American Lotus will likely return if no prolonged high water
events occur. Salvinia will likely increase, although the lake drawdown of 2020 has
reduced the total coverage in the lake.
0
50
100
150
200
250
300
350
400
450
500
4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
Number
Crappie 2000 Crappie 2001 Crappie 2015
22
Substrate
The frequent water level fluctuation that occurs in the Larto-Saline Complex promotes
increased decomposition of the organic layer in the substrate. The process improves the
suitability of the substrate for nesting sport fish species. The majority of the shoreline area is
wooded. This creates good buffer zones and helps to reduce sedimentation. Areas in close
proximity to Red River backwater inflow have an accumulation of silt.
Artificial Structure
The physical characteristics of the Larto-Saline Complex include an abundance of complex
cover including aquatic vegetation, standing trees, stumps, logs, and button bush. No
additional complex cover is necessary.
CONDITION IMBALANCE / PROBLEM
Since construction of the Catahoula Lake Diversion Canal in 1972, there have been numerous
failures of the spoil bank. Related consequences have included an uncontrolled hydrological
connection between the Larto-Saline Complex and the diversion canal. Despite the recent
replacement of the problematic Cross Bayou Weir, the potential for spoil bank failures at other
locations remains.
CORRECTIVE ACTION NEEDED
Due to the introduction and establishment of giant salvinia into the complex, it will likely be
necessary to conduct more foliar spray activities, weevil stocking, and lake drawdowns in the
future.
Consequences of the drawdown that was conducted in 2020 and the several days of freezing
temperatures and ice formation on the lake in February of 2021 need to be assessed before
making future decisions on lake management and vegetation control.
23
RECOMMENDATIONS
1. Continue LDWF standardized sampling to assess fisheries populations.
2. LDWF spray crews will continue treating emergent and floating vegetation as needed
following the guidelines in Table 6.
Table 6. LDWF Aquatic Herbicide Application Procedures.
Plant Species
Herbicide
Surfactant
Salvinia spp. Alternative 1
Common/Giant Salvinia
(April 1 to October 31)
Glyphosate (0.75 gal/acre)
Diquat (0.25 gal/acre)
Turbulence (or approved
equivalent, 0.25 gal/acre)
Salvinia spp. Alternative 2
Common/Giant Salvinia
(April 1 to October 31)
Glyphosate (0.75 gal/acre)
Flumioxazin (2 oz./acre)
Turbulence (or approved
equivalent, 0.25 gal/acre)
Salvinia spp. Alternative 3
Common/Giant Salvinia
(April 1 to October 31)
MSM (1 oz./acre)
Flumioxazin (1 oz./acre)
Turbulence (or approved
equivalent, 0.25 gal/acre)
Salvinia spp. Alternative 4
Common/Giant Salvinia
(November 1 to March 31)
Diquat (0.75 gal/acre)
Nonionic surfactant (0.25 gal/acre)
Salvinia spp. Alternative 5
Common/Giant Salvinia
(November 1 to March 31)
Flumioxazin (12 oz./acre)
Turbulence (or approved
equivalent, 0.25 gal/acre)
Water Hyacinth
2, 4-D (0.5 gal/acre)
Nonionic surfactant (1 pint/acre)
Water Hyacinth in waiver areas
(March 15 to September 15)
Glyphosate (0.75 gal/acre)
Nonionic surfactant (0.25 gal/acre)
Alligator Weed/Giant Cut Grass
(undeveloped areas)
Imazapyr (0.5 gal/acre)
Turbulence (or approved
equivalent, 0.25 gal/acre)
Alligator Weed/Giant Cut Grass
(developed areas)
Imazamox (0.5 gal/acre)
Turbulence (or approved
equivalent, 0.25 gal/acre)
American Lotus
2, 4-D (0.5 gal/acre)
Nonionic surfactant (1 pint/acre)
American Lotus in waiver areas
(March 15 to September 15)
Glyphosate (0.5 gal/acre)
Nonionic surfactant (0.25 gal/acre)
American Lotus in waiver areas
with potable water intakes
(March 15 to September 15)
Triclopyr (0.5gal/acre)
Turbulence (or approved
equivalent, 0.25 gal/acre)
Duckweed
Diquat (1.0 gal/acre) or
Flumioxazin (8 oz./acre)
Nonionic surfactant (0.25 gal/acre)
or Turbulence (or approved
equivalent, 0.25 gal/acre)
Cuban Bulrush (sedge)
2, 4-D (0.5 gal/acre)
Nonionic surfactant (1 pint/acre)
Cuban Bulrush (sedge) in waiver areas
(March 15 to September 15)
Glyphosate (0.75 gal/acre)
Nonionic surfactant (0.25 gal/acre)
Water Lettuce
Diquat (1.0 gal/acre) or
Flumioxazin (6 oz./acre)
Nonionic surfactant (0.25 gal/acre)
or Turbulence (or approved
equivalent, 0.25 gal/acre)
3. Continue aquatic vegetation surveys each summer to determine species composition and
area coverage.
24
APPENDIX I
LOUISIANA DEPARTMENT OF WILDLIFE & FISHERIES
OFFICE OF FISHERIES
INLAND FISHERIES AND
RESEARCH AND ASSESSMENT SECTIONS
Larto-Saline Lake Crappie:
Population Characteristics
Freshwater Report Series
Baton Rouge, Louisiana
2014
25
LOUISIANA CRAPPIE PROJECT
Larto-Saline Lake
Every fish population is the product of a unique set of influences, both natural and man-induced.
A thorough understanding of those influences and the corresponding population response is
essential to good fisheries management. As part of a statewide effort, the Louisiana Department
of Wildlife and Fisheries (LDWF) recently completed a study to describe the Larto-Saline Lake
Black Crappie and White Crappie (crappie) populations. The project included data collection
over a four-year period from 2009 – 2012. Population dynamics including relative abundance,
spawning success, growth, body condition, mortality, and longevity were measured.
Leadnet fishing gear was used to collect crappie from Larto-Saline Lake each fall. Length and
weight measurements were recorded for each fish and ear bones (called otoliths) were removed
from approximately 28% of the sampled fish for age and growth analyses. Annual growth rings
on the otoliths provide an accurate measurement of fish age. Since both species of crappie are
managed under the same harvest regulations, size and age for all of the sample fish were
combined to generate estimates of average growth rate and longevity.
Figure 1 illustrates that Larto-Saline Lake supports a healthy crappie population with some
individual crappie reaching 15 inches. Five to 12-inch fish were observed in all four years of the
project. It is important to note that fall leadnet sampling typically does not include young-of-the-
year size crappies. However, the recurring presence of small 5 to 10 inch (age-1) crappie
indicates successful reproduction from the previous year.
26
Figure 1. Length distributions of crappie collected from Larto-Saline Lake during fall leadnet
surveys in 2009-2012. Sample sizes (n) are presented in each graphic.
Age structure of the complete leadnet sample (2009-2012) is shown in Figure 2. Eighty-eight
percent of the total sample was comprised of age-1 and age-2 crappies. While crappie up to 7
years of age were found, only a small percentage of Larto-Saline Lake crappie were 4 years and
older. Average age at length for Larto-Saline Lake crappie is provided in Table 1. Growth is
generally good through age-1, but then slows to only two inches or less in length per year.
Body condition for Larto-Saline Lake crappie can be described as good. Good physical
condition of crappie generally is the product of an adequate food supply that is readily available
to predation.
Larto-Saline Lake exhibited moderately stable recruitment of age-1 crappies during the four-year
study. Consistently favorable spawning conditions for crappie are attributed.
Figure 2. The age structure of Larto-Saline Lake crappies 2009 - 2012.
0
200
400
600
800
1000
1200
0 1 2 3 4 5 6 7
Total Number Sampled
Age (Years)
n = 1,640
27
Age in Years
Length in Inches
2.02
8.0
2.95
10.0
4.46
12.0
Table 1. Average age at length for Larto-Saline Lake crappie.
The rate at which fish die each year is referred to as mortality. Mortality consists of two parts:
natural mortality (predation, disease) and fishing mortality (angler harvest and discard mortality).
Results of the study indicate that the total mortality rate for Larto-Saline Lake crappie is high
(81%) when compared to other recently sampled Louisiana lakes. The following example is
provided to illustrate the effect. At 81% mortality, if you start with 100 age-1 Larto-Saline Lake
crappie, 19 will remain alive by age-2, 4 by age-3 and less than one fish remaining by age-4.
The results of this study suggest that the Larto-Saline Lake crappie population has a total
mortality that is much more influenced by fishing mortality than by natural factors (56% and
25%, respectively). The fishing mortality rate for Larto-Saline Lake crappie is 56% per year.
This rate comes from two sources; 1) harvest and 2) post release mortality.
Population simulations illustrating the effects of two theoretical size regulations were calculated.
Using the mortality rate (81%) determined for Larto-Saline Lake, anglers would be required to
release 70% of fish caught with a 10” minimum length limit (MLL). A 12” MLL would require
anglers to release 92% of their catch. These effects increase as the minimum size limit increases,
but are less pronounced with higher natural mortality scenarios. Length limit implementation
would also increase the mean weight of crappie harvested (64% for 10” MLL and 166% for 12”
MLL), however the lower number of crappie harvested would result in decreased overall yield (-
14% for 10” MLL and -61% for 12” MLL).
SUMMARY
It is important to note that crappie populations and their fisheries are not only influenced by
fishing effort, but also by anthropogenic and environmental factors. The type and degree of
human activity within watersheds, riparian zones, and specific waterbodies can affect crappie
populations by altering critical habitats. Additional factors influencing crappie populations
include aquatic vegetation coverage, water level management, and habitat improvements. The
frequency of floods, drought, and hurricanes can also influence crappie populations. While
consideration of these factors is important in effective fisheries management, evaluating how
these factors affect the Larto-Saline Lake crappie population and fishery is beyond the scope of
this report.
The Larto-Saline Lake crappie population is influenced by natural and fishing related mortalities
for a combined rate of 81%. If natural mortality remains constant, no increase in crappie yield
should be expected from the protection of a 10” or 12” minimum length limit. Moreover, the
required release rates associated with both minimum length limits (70% and 92% respectively)
would be poorly received by anglers that pursue crappie for food.
Size distribution, recruitment levels, and fish condition for the last three years of the study were
found to be at levels that indicate a stable and healthy Larto-Saline Lake crappie population. The
fishery is currently managed with no size restrictions and a 50 fish per day harvest limit. Given
the dynamics of the Larto-Saline Lake crappie population, no change in angler harvest regulation
is recommended.
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APPENDIX II
Typemap
Larto-Saline Lake vegetation survey conducted on July 24
th
and 25
th
of 2013.
