W 2800.7 F532r no.26 1992/94 c.3
OKLAHOMA o
FISH RESEARCH AND SURVEYS FOR OKLAHOMA LAKES AND RESERVOIRS
FLATHEAD CATFISH ECOLOGY AND POPULATION STRUCTURE IN OKLAHOMA PRAIRIE STREAMS
MAY 1, 1992 through FEBRUARY 28, 1994 JOB TITLE: Flathead catrlSh ecology and population structure in Oklahoma prairie streams. CONTRACT PERIOD: May 1, 1992 through February 28, 1994 I. Proeram Narrative Objective Number 26:
To determine population structure and associations between biotic and abiotic
variables with abundance and distribution of the flathead catfISh, Pylodictis olivaris,
in Oklahoma prairie streams.
II. Introduction:
The flathead catfISh Pylodictis olivaris is native to the larger rivers of the Mississippi,
Missouri, and Ohio basins from the Great Lakes, Gulf of Mexico coastal plain, and Rio
Grande drainage into northeastern Mexico (Lee et al. 1980; Young and Marsh 1990; Quinn
1991). Non-native distribution from introductions and subsequent movements includes
Florida, South Carolina, Idaho, Oregon, Washington, Arizona and California (Lee and
Terrell 1987; Young and Marsh 1990). Flathead catfISh are an important fIShery resource throughout much of its range (Young and Marsh 1990; Pugibet and Jackson 1991), due to its fighting ability (McCoy 1955), large size (Quinn 1991), and palatable flesh (Jordan and Evermann 1920). Investigations of flathead catfISh populations from lotic waters have primarily centered around age and growth, population structure, movement, and food habits (Funk 1955; Cross and Hasting 1956; Minckley and Deacon 1959; Mayhew 1969;
Cross and Hastings 1956; Guier et al 1981; Weeks and Combs 1981; Dames et al. 1989;
Quinn 1988; Young and Marsh 1990; Coon and Dames 1991; Quinn 1991; Insaurralde
1992). Major accounts of flathead catfISh habitat use have typically been descriptive
(Minckley and Deacon 1959; Cross 1967; Miller and Robison 1973; Pflieger 1975; but see
Coon and Dames 1991; Insaurralde 1992) and have not discussed the habitat requirements of young-of-year flathead catfISh in streams lacking riffles (Lee and Terrell 1987). In Oklahoma, the flathead catfISh is a highly preferred sport species (Summers 1990), reaching a weight of 48 kilograms. It is typically described as being common in larger lakes and streams (Miller and Robison 1973). Based on a 1990 survey of state game wardens (unpublished data, Oklahoma Department of Wildlife Conservation) it was suspected that significant fIShing pressure is being placed on flathead catfISh stocks in rivers and streams. Methods employed include rod and reel, trotline, limb line, bank sets, and noodling. In 1991 the Oklahoma Department of Wildlife Conservation (ODWC) imposed a statewide 508 mm minimum length limit to an existing daily creel limit of 10 flathead catfISh. It was reasoned the additional limits were warranted based upon the popularity of the species. Despite its popularity, little ecological information is available on stocks of flathead catfISh in Oklahoma (Gilliland 1987) or other paris of the Southwest (Young and
Marsh 1990). The available information concerning Oklahoma flathead catfISh stocks is primarily based on reservoir sampling (McCoy 1955; Jenkins 1954; Turner and Summerfelt
1971a; Turner and Summerfelt 1971b; Weeks and Combs 1981; Gilliland 1988).
Flathead catfish may be as vulnerable to overharvest as other species, such as largemouth bass (Quinn 1991). The purpose of this study was to determine habitat use, population structure, and length-weight relationships of the flathead catfISh in selected
Oklahoma prairie stream systems.
Electrofishine survey.-- Road surveys of six Oklahoma prairie streams for areas of suitable boat access and suitable electrofishing locations were conducted from 19 May to 9 June 1992. During these road surveys angler access to these streams from public roads was also recorded.
From 18 June 1992 to 16 March 1993, flathead catflSh were sampled from Oklahoma prairie stream systems. Six streams were sampled by electrofishing from 18 reach access locations chosen during the road surveys (Table 1). One hundred forty-five sites were electroflShed for flathead catflSh abundance and habitat relationships. ElectroflShing was conducted with a Smith-Root 5.0, gas powered pulsator (GPP). The GPP was mounted in a 4.3 m, flat bottom, aluminum boat. Eight anodes, constructed of 100 cm long stainless steel cable, were attached to a ring 50 cm in diameter. The ring was mounted on a 180 cm boom, extending from the front of the boat. The hull of the boat served as the cathode.
Effective electrofishing settings encountered for flathead catfish were 15 pulses per second
(pps) at 2-9 amps. These settings were also appeared effective for electrofishing blue catflSh
Ictalurns furcatus. A site was electrofished for 3 minutes with the boat stationary, while a second boat with two personnel was used to collect surfacing flathead catfish. In addition to the 145 stationary electroflShing sites, other areas within a reach were electroflShed for flathead catfish with the GPP boat moving. Estimates of forage fish were made within the reach sections by electroflShing with a pulse setting of 120 pps. Other flSh species surfacing during electroflShing efforts were recorded. Also, presence of anglers at time of sampling was recorded.
Twenty-six variables were recorded at each of the 145 stationary electrofishing sites along with 8 variables recorded at the reach level. Due to daily fluctuations, water temperature was initially eliminated from the analyses. Based on preliminary correlation analyses, twenty of the original variables were chosen for the final analyses (Table 2).
Continuous variables were log-transformed (JOgIO(Nor N+ 1» to meet the assumptions of nonnality and constant variance (Sokal and Rohlf 1981). The variables and transfonnations (N+ 1) were: average depth (measured with a LCR depth finder), average width, number of debris piles (N+ 1), number of isolated logs (N+ 1), number of blue catfish (N+l), altitude (obtained from 1:24,000 scale topographic maps), conductivity, secchi depth, Julian date (N+ 1), (for the following categorical variables: 0 = not a maj or component; 1 = was a major component) current, slope, shade, stability, mud, clay, sand, boulders/riprap, submerged debris (estimated using a LCR depth finder), angler pressure
(bank/trotlines), and shad abundance. Flathead catfish collected during stationary and moving electrofishing were measured for total length (mm), weighed (g) and released.
Flathead catfISh observed surfacing, but not collected, were recorded with an estimate of total length. For analyses the observed catfISh were subsequently placed into 3 broad
length groups: ~349 mm, 350-509 mm, ~510 mm.
Relationships were investigated for 112 stationary electrofishing sites from 19 reach samples. Sites with no flathead catfISh were eliminated since absence of fISh during
electroflShing could be due to reasons not associated with the variables recorded. For one
reach that was sampled twice (E18 and EI8a), both samples were included since they were
separated by substantial time (57 days) and the environmental conditions had changed
drastically (personal observation). Prior to analyses flathead catfISh were classified into two
groups: juveniles « 350 mm) and adults ~350 mm), based on the minimum maturity
length for flathead catfish in rivers (Turner and Summerfelt 1971a). The abundance data were log-transformed (lOgIO(N+ 1)) prior to analyses to improve homogeneity of variances and normalities (Sokal and Rohlf 1981). All categorical data were included in the analyses as dummy variables generated by effects coding (for two groups = -1, + 1). This method produces parameter estimates that are differences from both groups taken as an aggregate, since neither group is designated as a reference group (Cohen and Cohen 1983).
Relationships between juvenile and adult abundances and habitat use were evaluated by forward stepwise multiple linear regression. Because the 112 sites were obtained from
19 reach samples, they cannot be considered statistically independent. Thus, we used a method that analyzes for within-reach variation after removing the effect of reaches
(Robertson et aI. 1993). This was accomplished by initially forcing into the model effects coded dummy variables for each reach sample. This produced reach coefficients (RCs) that characterized between-reach differences. We then analyzed for between-reach variation by entering as the dependent variable the RCs against the variables recorded for each reach, along with the mean of variables recorded at each site. During all analyses alpha-to-enter and alpha-to-remove was set at 0.15. Only variables with P ~ 0.05 were included in the final models.
Juvenile and adult abundance data were compared among reaches and rivers using a one-way analysis of variance (ANOVA). Post hoc pairwise multiple comparisons were made using the Tukey-Kramer HSD test. Population structure data was analyzed after combining lengths of flathead catfISh collected into the broad length categories of observed flathead catfish ~349, 350-509, L510 mm). Percentages of fish in each broad length group were compared between rivers, using pairwise G-tests of independence (Sokal and Rohlf 1981). To control the tablewide alpha level, probabilities were adjusted using the sequential Bonferroni technique (Rice 1989). Flathead catfish size structure was also analyzed using the length categorization system presented by Gabelhouse (1984). The indices proportional stock density (PSD) and Relative stock density (RSD) were calculated for the six rivers according to lengths proposed by Quinn (1991). Flathead catfISh sampled during 1993 were not included in abundance and size structure analyses, due to low water temperatures (9.5-11.5° C), which were below temperatures (16-200C) needed to properly assess populations of flathead catfish with electrofishing (Weeks and Combs 1981; Quinn
1988).
Length-weight relationships of flathead catfish ~100 mm were analyzed using simple linear regressions. Total length and weight were 10glO-transformed prior to the analyses.
Flathead catfISh collected during stationary and moving electrofishing were included in the analyses, along with one large individual (930 mm) collected from the Washita River drainage during seining. Regressions were performed on reaches, rivers and collectively statewide. After checking for the assumption of no interaction, the slopes of regression lines between reaches and between rivers were compared using an analysis of covariance
(ANCOVA). Only reaches with at least 10 fish measured and weighed were used. Post hoc pairwise multiple comparisons were made using Tukey-Kramer HSD test. As a measure of condition, relative weight (Wr) was calculated for fISh ~280 mm, using the following
standard weight (Ws) equation:
LogIOW.= -5.156 + 3.082 LogioTL
(Murphy et aI. 1991). Next, fish were placed into 20 mm length groups, and mean Wr was calculated for each river and collectively for all rivers.
Seinin2 survev.--One hundred fifteen sites were sampled for abundance and habitat use by juvenile flathead catfish (Table 3), using a 1.8 X 4.5 m, .5 cm mesh, double lead line seine. One hundred eight of these sites were sampled from 50 to 60 minutes for a distance of 100 to 150 meters, depending upon stream size. Efforts were made to sample all available habitat types at each site. The other 7 sites were limited to 10 to 15 minute samples, in habitat types believed to be preferred by juvenile flathead catfish. Thirty-one variables were recorded for each site. Water temperature was initially eliminated from further analyses due to daily fluctuations. Based on preliminary correlation analyses, 21 variables were included in the final analyses (Table 4). Logarithmic transformations (log\O
(N or N+1)) were applied to continuous variables to meet assumptions of normality and constant variance (Sokal and Rohlf 1981). The variables and transformations (N+ 1) were: average width, average depth, number of debris piles (N+1), number of logs (N+1), altitude (obtained from 1:24,000 scale topographic maps), conductivity, secchi depth, Julian date, current: 0 = none, 1 = slow, 2 = moderate, 3 = swift, (for the following categorical variables: 0 = not a major component; 1 = a major component) slope, shade, stability, riffles, undercut, (the following variables were coded 0-1 based on abundance of each) mud, clay, sand, gravel, cobble, boulders/riprap, and detritus.
Seining data from 1992 were analyzed for the distribution of juvenile flathead catfISh after eliminating 1 site due to repeat sampling and 2 individuals of exceptional size (381 mm and 930 mm). Data from 1993 were not included in the analyses due to low capture rates
(N=2), which may solely have been due to sampling in different years. A principal components analysis (PCA) was used to analyze a correlation matrix of the 21 variables
(standardized) to reduce the dimensionality of the data into a few components, that explains the majority of the variance. The first 4 axes of the PCA (unrotated) were retained for further analyses. Only variable loadings (correlations) of ~0.40 were considered in interpreting a principal component (PC). On an individual PC, variables with the same sign are considered positively intercorrelated. The different PCs are uncorrelated.
Scatterplots of the PCs were formed to show similarity of the sample localities. The localities were plotted after coding each for presence/absence of juvenile flathead catfish.
To see if presence/absence varied on a PC, the plot coordinates were log-transformed (LogiO
(N+4», and subjected to an one-way ANOVA. Microhabitat associations with any structure and flow (non-flow = slow or still) were recorded at any specific points where juvenile flathead catfish were collected (for 1992-93).
All fish collected during seining, except large individuals, were preserved in 10% formalin and transported back to the laboratory for identification. Larger fish were identified and released in the field. Preserved specimens will be housed permanently in the
Oklahoma Museum of Natural History, University of Oklahoma, Norman. All analyses were performed using SYSTAT (SYSTAT Incorporated 1992). Results were considered significant at P ~ 0.05.
IV. Results
Electrofishin2 survey.--In 1992-93 electrofishing, 310 flathead catfISh were collected during electroflShing with another 448 flathead catfish observed (Table 5). Results from the multiple-regression analyses of within-reach effects on abundance of juveniles (AJ) was best predicted by:
AJ = 0.380 + -0.228-0.326X1-X1S+ 0.076X19+ 0.559X20 + 0.076Xw
where Xl-XIS= reaches, Xl9 = current, X20 = number of debris piles and, X2l = stability.
The equation has an adjusted R2 of 0.37 and P < .001 (N = 112, DF = 21, F = 4.12).
The specific variance accounted for by the variables X19-X21was 14%. No variables
significantly predicted with-in reach effects on the abundance of adults (AA).
In the analyses of between-reach effects, the best predictor of reach coefficients
representing juvenile abundance (JRC) was:
iRe = 0.142 + 0.387XI - 0.814X2 - 0.255X3 + 0.294X4,
where Xl = boulders/riprap, X2 = average depth, X3 = stability and, X4 = clay. The
equation has an adjusted R2 of 0.75 and P < 0.001 (N = 19, DF = 4, F = 14.65). The
best predictor of reach coefficients representing adult abundance (ARC) was:
ARC = -1.942 + 0.718XI + 0.517X2 + 0.460X3,
where Xl = Julian date, X2 = number of logs, and X3 = number of debris piles. The
equation has an adjusted R2 of 0.59 and P = 0.001 (N = 19, DF = 2, F = 9.51).
Results of the ANOVA show juvenile abundance varied significantly among reaches
(P = 0.001), with the Cimarron differing significantly from the Washita Chickasha,
Washita Tishomingo(E18), Chikaskia above lake, Little River, and Chikaskia Tonkawa
reaches. Juvenile abundance for rivers was also significantly different (P < 0.001), with
the Cimarron differing from all rivers, except the Deep Fork. Comparison of adult
abundance among reaches was significantly different (P = 0.002), with the Chikaskia above
lake differing significantly from the Washita Verdin, Washita Chickasha, Washita Dougherty, Washita Mannsville, Deep Fork Gypsy, Deep Fork Ofuskee, and Muddy Boggy
Gay reaches. Comparison of adult abundance among rivers was also significantly different
(P = 0.004), with the Chikaskia differing significantly from the Washita and Deep Fork
Percentage comparisons of the broad length-frequency distributions among rivers
(Figure 1) found the Little River differed significantly from the Chikaskia (P < 0.05). The
Little River also differed from the other rivers (P < 0.001), as did the Chikaskia (P <
0.05). Flathead catfish < 350 mm were most abundant (Table 6). For all rivers, only 14% of fish were ~ 350 mm. Length-categorization data (Table 7) shows that the majority of flathead catfish collected > 350 mm were between the 350 to 709 mm. For fish collected and observed, PSD values ranged from 47 in the Muddy Boggy to 83 in the Little River.
Collections of memorable to trophy sized fish (865-1,019 mm) were low, although 1 fish from the Washita, 1 fish from the Deep Fork, 2 fish from the Muddy Boggy and 4 fish from the Chikaskia were observed and estimated in this size range. Collection or observation of trophy sized fish (> 1,020 mm) was rare or absent.
Results of simple linear regressions for length-weight relationships show the slope values for each river and all rivers collectively were> 3 (Table 8). Reaches with n~10 also had slope values > 3 (Table 9). The ANCOVA comparison among reaches was highly significant (P < 0.001), with statistical differences for: (1) the Washita Chickasha(13a) from the Washita Tishomingo(18a), Muddy Boggy Lane, and Chikaskia below lake reaches; and (2) the Cimarron Oilton from the Washita Tishomingo(18a), Muddy Boggy Lane and
Chikaskia below lake reaches. The ANCOVA comparison among rivers was also significant (P < 0.001), with the Cimarron differing significantly from the Muddy Boggy. The mean
Wr for each river ranged from 77 to 120 (Table 10). Only the Cimarron and Little River
had a majority of groups with Wr> 100. For all rivers, mean Wr increased with fish size and ranged from 79 to 113 (Table 11).
Results of other species collected during electrofishing (Table 12) show blue catfish were abundant in the Washita River. They were also commonly found in the lower Muddy
Boggy, Cimarron, and Deep Fork rivers. Channel catfish were collected abundantly from the lower Cimarron River. Only one rare species was collected, an individual blue sucker from the lower Muddy Boggy River.
Seinin2 survev.--Seine collections during 1992-93 produced 55 flathead catfish. The first 4 axes of the PCA accounted for 54.2% of the total variance (Table 13). Only PC2 had localities with significant differences in the presence/absence of juvenile flathead catfISh
(P = .049). A scatterplot of PCl and PC2 (Figure 2) shows that on PC2, juvenile flathead catfISh are found more often in lower altitude stream areas with logs, cobble and boulders versus smaller, higher altitude stream areas. This scatterplot gives a representation of where juvenile flathead catfish are typically found in Oklahoma prairie stream systems.
For all juveniles collected during 1992-93, microhabitat data indicated 94% were associated with rock and/or wood, while 96% were associated with flow (Figure 3).
Results of other species collected during seining (Tables 14 & 15) indicate channel catfISh are commonly found in abundance throughout prairie river systems. The majority of these individuals were young-of-year. Young-of-year blue catfish were also abundant in the lower Washita River. Results from the Washita River drainage provide the first comprehensive assessment of the distribution and abundance of its fishes, including a range extension of central stonerollers (Milligan and Lemmons 1993).
V. Discussion
Flathead catfISh in Oklahoma prairie streams appear significantly oriented towards instream structure. Fish observed during moving electrofIShing support these findings, since > 95% surfaced by instream structure (personal observation). Associations with boulders/riprap, logs, and debris piles are in agreement with qualitative river habitat given by Minckley and Deacon (1959), Cross (1967) and Pflieger (1975). Also verifying a strong relationship for instream structure, Coon and Dames (1991) found larger flathead catfISh preferred log and standing tree/root complexes, while Insaurralde (1992) found larger flathead catfish associated with snags. A strong correlation was found in this study between adult flathead catfISh Young-of-year flathead catfish generally inhabit swift riffle areas (Minckley and Deacon 1959; Cross 1967; Pflieger 1975). This electrofishing study provides quantitative habitat description of flathead catfish in streams lacking riffles. Juveniles (which included young-of-year) were found associated with shallow depths, containing debris piles and boulders/riprap versus riffles, although they still inhabited current. Results of the seine survey indicated juveniles were associated with logs, cobble and boulders/riprap. The majority of cobble was due to human introduction for bank stabilization. This cobble often provides riffle-like habitat in streams. Some of the upland areas seined did contain natural riffles, although flathead were usually absent. Presumably this is because flatheads avoid stream areas of higher gradient (Pflieger 1975). Microhabitat associations also support the positive association of rock/timber structure and flow with juvenile flathead catfish. Flathead catfish are often associated with larger streams or rivers (Moyle 1971; Miller and Robison 1973; Pflieger 1975). Our findings agree with this description, although flathead catfISh were often seined from smaller streams of lower altitudes. While these individuals were typically juveniles, adults also utilize these areas. A 930 mID individual was collected from a stream section averaging 3.5 m in width and 0.2 m in depth, > 3 kID upstream from the Washita River. In Oklahoma prairie streams, flathead catfISh distribution should thus be considered to include small streams at lower altitudes, along with bigger streams and lakes (Miller and Robison 1973). Juvenile flathead catfISh were most abundant in electrofIShing samples from the Cimarron River reach, while other reaches on the Deep Fork River and the Washita River appeared low in abundance. These comparisons should be considered with caution because juvenile abundances are likely biased by time of the year a location is sampled. For example, the Washita River was sampled twice at the location SW of Tishomingo (Table 1). Efforts earlier in the year produced 22 juveniles from 12 sites while efforts later in the year produced 86 juveniles from only 8 sites. Differences in juvenile abundances may have been influenced by differences in water level (Pierce et al. 1985) or higher abundances due solely to presence of hatched fish (Schlosser 1985). Adults were typically more abundant in the lower reaches of rivers or sections that were in close proximity to a reservoir. Based on the broad length frequencies for rivers (Figure 1), the majority of flathead catfish were below 350 mm (86%). Only 8% were above 510 mm (20"). These percentages seem low when compared with electrofishing samples from other rivers. Young and Marsh (1990) found almost 74% above 407 mm, 38% above 400 mm and 35% above 448 mm, respectively from 3 rivers (AZ). Pugibet and Jackson (1988) found 18% above 500 mm in the Noxubee River (MS). Weeks and Combs (1981) found 15.0% > 360 mm (1977-78) and 18.9% >400 mm (1978-79) in Webbers Falls Reservoir (OK), a navigation waterway system on the Arkansas River. Weeks and Combs (1981) also found commercial fIShing of Webbers Falls Reservoir had low exploitation rates « 5%) for flathead catfISh> 400 mm. Quinn (1988) found> 25% above 500 mm in the Flint River (GA), which he considered having low exploitation. As a contrast, Hesse et al. (1976) found only 2.1 % (1971), 1.5% (1974) and 3.0% (1975) of flathead catfish > 500 mm in the Missouri River (NE), which presumably had low numbers of large fish due to commercial exploitation. Schoumacher (1968) also found an abundance of smaller flathead catfish in the Mississippi River bordering Iowa, which he concluded was due to commercial fishing. The Oklahoma percentage falls in between the low percentage of the heavily exploited Missouri River and the higher percentage of the lightly exploited Flint River . Length-categorization of electrofIshing results (Table 7) show that the majority of flathead catfish > 350 mm, collected from Oklahoma rivers, between the 350 to 709 mm length ranges. Comparisons of PSD for flathead catfish collected and observed with length categorization data from the lightly exploited Flint River in Georgia (Quinn 1991), show they are close in value. For fish collected, 67% of Oklahoma prairie rivers have higher values for length categories> 710 mm than the Flint River. Two Oklahoma rivers had fish collected in the trophy size range. A major difference between length categorization calculations from the Flint River and Oklahoma rivers is Quinn (1991) collected 3,266 flathead catfish of which 44% were greater than the minimum stock length, while 308 flathead catfish were collected from Oklahoma rivers with only 18% (14% for collected and observed) greater than the minimum stock length. The low abundance for Oklahoma rivers of trophy sized flathead catfish (> 1020 mm) seems suggests exploitation, although this size group may naturally be rare in streams. Comparisons indicate this size group typically only makes up a between 0-5% of all flathead catfish collected (Hesse et al. 1976, Quinn 1988, Young and Marsh 1990, Pugibet and Jackson 1991, Insaurralde 1992). The length- categorization values for Oklahoma rivers indicate the potential to produce a quality river fIShery for flathead catfISh, with some individuals reaching considerable length. Length-weight relationships for rivers show flathead catfish have become more rotund as their length has increased. This is indicated by the regression slope values which are > 3.0 (Anderson and Gutreuter 1984). The reaches with n~10 and rivers are very similar in slope value, with only 2 reaches (Washita Chickasha(13a) and Cimarron Oilton) and 1 river (Cimarron) differing from any other samples. The 1992 statewide regression slope for prairie streams compares favorably with past statewide reservoir slopes reported by Houser and Bross (1963) and Mense (1976) (Table 8, Figure 4). The statewide regression equations indicate a flathead catfish 500-510 mm should weigh 1.3-1.5kg (Table 16). Conditions based on mean Wr seem to be near values that are usually considered acceptable for other species (90-100) (see Murphy et aI. 1991). Based on mean Wr' the Cimarron and Little River both have fish in what is considered an exceptionable condition (Wr> 100), although no publications have yet evaluated acceptable ranges for the flathead catfISh. It appears that riverine fIShery stocks receive abundant pressure (Table 17). At times this pressure may be extreme, such as the Washita River at Chickasha. This location is behind a dam and draws anglers as far away as Oklahoma City (personal observation). What should be considered is that this survey of fIShing pressure is very limited, and does not reflect usage by noodling, netting, snaglines or any illegal activities. River access from public roads does not seem to be limited for bank anglers, or for anglers with a light boat and motor (Table 18). The Chickasha access is privately owned, but has a public pay gate. The amount of private land being used to access rivers is not known, but when combined with public access, portions of Oklahoma prairie rivers are highly accessible. VI. Recommendations 1. Most (92%) of flathead catfish sampled were less than 508 mm TL, suggesting significant angling pressure. Additional restrictive regulations may be required to maintain flathead catfISh fISheries in Oklahoma rivers. 2. Trophy size (> 1,020 mm) and other large flathead catfish appear rare in Oklahoma prairie rivers. Anglers may be over-exploiting the large flathead catfish fIShery in Oklahoma rivers. Evaluation of angler techniques should compare their harvest potential for abundance and size. This study should be done before, during, and after the spawn to assess if techniques temporally differ in effectiveness. 3. Flathead catfISh appear structure oriented. Thus any management plans that include the removal of debris from a river will likely harm populations. Currently, woody debris appears abundant in Oklahoma prairie rivers (personal observation). Indications are that bank revetment may increase the abundance of juveniles within an area. 4. Evaluation of the effectiveness of electrofish sampling for flathead catfish during the spawn is needed. Our early season results indicate this to be a potential bias when evaluating reproductive size fish. 5. Flathead catfISh abundance among years within a given reach needs to be evaluated. It is currently unknown if the patterns we found are consistent from year to year. Selected river locations should be electrofished in late summer to avoid the spawn. 6. 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Proceedings of the Annual Conference of the Southeastern Association of Fish and Wildlife Agencies 41(1987):221-229. Guier C.R., L.E. Nichols, and R.T. Rachels. 1981. Biological investigations of flathead catfIsh in the Cape Fear River. Proceedings of the Annual Conference of the Southeastern Association of Fish and Wildlife Agencies 41(1987):221-229. Hesse L. W., C. R. Wallace, and L. Lehman. 1976. Fishes of the channelized Missouri. Age-growth, length-frequency, length-weight, coeffIcient of condition, catch curves and mortality of 25 species of channelized Missouri River fIshes. Nebraska Game and Parks Commission. Houser A. and M. G. Bross. 1963. Average growth rates and length-weight relationships for fIfteen species of fIsh in Oklahoma waters. Bull. No. 85 Okla. Fish. Res. Lab., 75pp. Insaurralde M.S. 1992. Environmental Characteristics Associated with Flathead CatfISh in Four Mississippi Streams. Doctoral dissertation. Mississippi State University. Jenkins R.M. 1954. Growth of the flathead catfIsh, Pilodictus olivaris, in Grand Lake (Lake 0' The Cherokees) Oklahoma. Proceedings of the Oklahoma Academy of Science 33(1952):11-20. Jordan D.S. and Evermann B.W. 1920. American Food and Game Fishes. Doubleday, Page, and Company. New York. Lee D. S., C. R. Gilbert, C. H. Hocutt, R. E. Jenkins, D. E. McAllister, and J. R. Stauffer Jr. 1980. Atlas of North American Freshwater Fishes. North Carolina State Museum of Natural History. Lee L. A. and J. W. Terrell. 1987. Habitat suitability index models: flathead catfISh. Biological Reports 82. United States Fisheries Wildlife Service, National Ecology Research Center. Fort Collins, Colorado. Mayhew J.K. 1969. Age and growth of flathead catfISh in the Des Moines River, Iowa. Transactions of the American Fisheries Society 98:118-121. McCoy R.A. 1955. The rate of growth of flathead catfISh in twenty-one Oklahoma lakes. Proceedings of the Oklahoma Academy of Science 34 (1953):47-52. Mense J. B. 1976. Growth and length-weight relationships of twenty-one reservoir fIShes in Oklahoma. Bull. No. 13, Okla. Fish. Res. Lab., 155pp. Miller R. J. and R. W. Robison. 1973. The Fishes of Oklahoma. Oklahoma State University Press, Stillwater. Milligan A. R. and R. P. Lemmons. 1993. Occurrence of the Central Stoneroller (Campostoma anomalum) in the upper Washita river drainage. Proceedings of the Oklahoma Academy of Science 73:71-72. Minckley W.L. and J.E. Deacon. 1959. Biology of the flathead catfISh in Kansas. Transactions of the American Fisheries Society 88:344-355. Moyle P. B. 1976. Inland fIShes of California. University of California Press, Berkeley. Murphy B. R., M. L. Brown, and T. A. Springer. 1991. The relative weight index in flSheries management: status and needs. Fisheries 16:30-38. Pierce R. B., D. W. Coble, and S. D. Corley. 1985. Influence of river stage on shoreline electroflShing catches in the upper Mississippi River. Transactions of the American Fisheries Society 114:857-860. Pflieger W.L. 1975. The Fishes of Missouri. Missouri Department of Conservation. Pugibet E.E. and D.C. Jackson. 1991. Sampling flathead catflSh in small streams. Proceedings of the Annual Conference of the Southeastern Association of Fish and Wildlife Agencies 43(1989):133-137. Quinn S. P. 1988. Effectiveness of an electrofishing system for collecting flathead catflSh. Proceedings of the Annual Conference of the Southeastern Association of Fish and Wildlife Agencies 40(1986):85-91. -----. 1988. Stomach contents of flathead catfish in the Flint River, Georgia. Proceedings of the Annual Conference of the Southeastern Association of Fish and Wildlife Agencies 41(1987):85-92. -----. 1991. Evaluation of a length-categorization system for flathead catflSh. Proceedings of the Annual Conference of the Southeastern Association of Fish and Wildlife Agencies 43(1989):146-152. Ramsey D. and L. K. Graham. 1991. A review of literature on blue catfish and channel catflSh in streams. Final report. Missouri Department of Conservation. Rice W. R. 1989. Analyzing tables of statistical tests. Evolution 43:223-225. Robertson P.A., M.I.A. Woodburn, and D.A. Hill. 1993. Factors affecting winter pheasant density in British woodlands. Journal of Applied Ecology 30:459-464. Schlosser I. J. 1985. Flow regime, juvenile abundance, and the assemblage structure of stream lishes. Ecology 66:1484-1490. Schoumacher R. 1968. Some observations on flathead catlish in the Mississippi river bordering Iowa. Transactions of the American Fisheries Society 97:65-66. Sokal R.R. and F.J. Rohlf. 1981. Biometry, 2nd edition. Freeman, San Francisco. Summers G.L. 1990. Oklahoma angler opinion survey, 1990. Okla. Dept of Wildf. Conserve Final Report. F-37-R(3), 26pp. SYSTAT Incorporated. 1992. SYSTAT for Windows, version 5.02. SYSTAT Incorporated, Evanston, lllinois. Turner P.R. and R.C. Summerfelt. 1971a. Reproductive biology of the flathead catfISh, Pylodictus olivaris, in a turbid Oklahoma reservoir. Pages 107-119 in G. Hall, editor. Reservoir Fisheries and Limnology. American Fisheries Society, Bethesda, Maryland. 1971b. Condition factors and length-weight relationships of the flathead catfISh, Pylodictus olivaris (Ralinesque), in Lake Carl Blackwell. Proceedings of the Oklahoma Academy of Science 51:36-40. Weeks H. and D. Combs. 1981. Oklahoma Commercial Fisheries Project: Commercial Lake Monitoring Study. Final Report. NMFS PROJECT 2-237-R(1). Oklahoma Department of Wildlife Conservation. Young K. L. and P. C. Marsh. 1990. Age and growth of flathead catfISh in four southwestern rivers. California Fish and Game 76:224-233. Table 1. Locations of electrof iShing access for flathead catfish in Oklahoma prairie streams, 1992-93. LOCATION # COUNTY DATE LOCATION-LEGAL SITE CHIKASKIA RIVER E1 Kay 7/30/92 Above L. Blackwell-S28,29,34 T29N R2W E2 Kay 7/30/92 Below L. Blackwell dam-S34,35 T29N R2W E3 Kay 9/24/92 3m SE Tonkawa-818,19 T25N R1E MUDDY BOGGY RIVER E4 Coal 8/13/92 8E Lehigh-829 T18 R11E E5 Atoka 8/13/92 NE Bruno-826,35,36 T28 R12E E6 Choctaw 8/20/92 2m W Gay-816,23.24 T78 R16E LITTLE RIVER E7 Cleveland 9/3/92 Above L. Thunderbird-86.8.17 T9N R1W CIMARRON RIVER E8 Creek 9/17/92 8W Oilton-85,8 T18N R7E DEEP FORK RIVER E9 Lincoln 7/2/92 8 Chandler-833,34.35 T14N R4E E10 Creek 7/2/92 8W Gypsy-836 T14N R7E E11 Okfuskee 8/27/92 NW Okfuskee-85.8 T13N R10E WASHITA RIVER E12 Caddo 6/18/92 NW Verdin-89.17 T7N R9W E13 Grady 6/18/92 8E Chickasha(dam)-81,2 T6N R7W E13a 10/1/92 E13b 3/16/93 E14 Garvin 7/9/92 NW Pauls Valley(HW 77)-86 T4N R1W & 81 T4N R2W E15 Garvin 7/9/92 W Wynnewood(HW 77)-815,16 T2N R1E E16 Murray 7/13/92 W Dougherty-8 11,13,14 T48 R4E E17 Johnston 7/13/92 NE Mannsville-814.23 T48 R4E E18 Johnston 7/21/92 8W Tishomingo-88,17 T48 R6E E18a 10/15/92 25 Table 2. Summary of variables used in regression analyses of flathead catfish from Oklahoma prairie streams, 1992. Variables recorded for each site Average depth (m) 1.4 0.6 0.6-3.6 Average width(m) 36.3 25 12.1-121.2 Number of debris piles 0.6 0.6 0-2 Number of logs 1.4 1.4 0-5 Current 0.4 0.5 0-1 Slope 0.4 0.5 0-1 Shade 0.6 0.5 0-1 Stability 0.6 0.5 0-1 Mud 0.1 0.2 0-1 Clay 0.3 0.5 0-1 Sand 0.8 0.4 0-1 Boulders/riprap 0.2 0.4 0-1 Submerged debris 0.8 0.4 0-1 Number of blue catfish 1.4 3.4 0-20 Variables recorded for each reach Altitude (m) 245.9 59.4 136-349 Conductivity 1069 791.7 151-3698 Secchi (cm) 20.8 11 5-46 Julian date 215.6 33.9 170-289 Angler pressure 0.6 0.5 0-1 Shad 0.4 0.5 0-1 S1 Roger Mills Washita R. 7/14/92 4.25m W 2.75m N Cheyenne-S33 T14N R23W S2 Roger Mills Washita R. 7/14/92 7.5m W 1.5m S Strong City-S14 T13N R22W S3 Custer Washita R. 7/14/92 1m E Fossdam-S31 T13N R18W S4 Grady Washita R. 6/23/92 2m SE Chickasha (by boat}-S1 T6N R7W S5 Grady Washita R. 6/23/92 2m SE Chickasha (below dam}-S1 T6N R7W S6 Caddo Washita R. 6/16/92 4.5m W Verdin (by boat}-S8 T7N R9W S7 Caddo Washita R. 6/16/92 4.5m W Verdin (by boat}-S17 T7N R9W S8 Caddo Sugar Cr. 6/16/92 5m W 1m N Verdin-S8 T7N R9W S9 Custer Washita R. 10/6/92 4.5m E 1.5m N Hammon-S27 T14N R20W S10 Custer Washita R. 10/6/92 3.5m E 3m N Hammon-S21 T14N R20W S11 Custer Washita R. 10/6/92 .5m E 2m N Hammon(HW 34}-S19 T14N R20W S12 Garvin Wild horse Cr. 9/10/92 1-35bridge-S28 T1N R1E S13 Murray Washita R. 9/10/92 1m W Doughtery-S 11 T2S R2E S14 Garvin Rush Cr. 9/10/92 W of HW77 bridge-S17 T3N R1E S15 Roger Mills Washita R. 8/4/92 4m S of HW33-S20 T15N R26W S16 Roger Mills Washita R. 8/4/92 2.75m N 4.5m W Cheyenne-S33 T14N R24W S17 Carter Caddo Cr. 9/8/92 S of Springer(HW77)-S31 T3S R2E S18 Carter Caddo Cr. 9/8/92 3m SSW Gene Autry-S 1 T4S R2E S19 Carter Caddo Cr. 9/8/92 1.5m NW Graham-S30 T2S R2W S20 Carter Caddo Cr. 9/8/92 1.5m NE Graham-S29 T2S R2W S21 Murray Honey Cr. 8/6/92 .5m W of 1-35bridge-S18 T1S R2E S22 Murray 8-mile Cr. 8/6/92 2m S of HW 7(Morton's ranch}-S7 T1S R1W S23 Carter Caddo Cr. 8/6/92 1m SW Milo-S6 T3S R1W S24 Johnston Mill Cr. 9/28/92 3m W Ravia-S7 T4S R5E S25 Murray Chigley Sandy Cr. 9/28/92 1m N Davis(HW 77}-S32 T1N R2E S26 Custer Washita R. 9/22/92 7m E Clinton(HW 73}-S22 T12N R18W S27 Washita Washita R. 9/22/92 1.5m W of HW 115-S34 T8N R15W S28 Johnston Washita R. 7/20/92 2m SW Tishomingo-S8 T4S R6E S29 Johnston Washita R. 7/20/92 3m SW Ravia(HW 1}-S8 T4S R5E S30 Garvin Washita R. 7/20/92 4m E Maysville-S18 T4N R1W S31 Grady Bitter Cr. 10/13/92 3m SE Chickasha-S9 T6N R6W S32 Caddo Delaware Cr. 10/13/92 4m E 1m S Anadarko-S29 T7N R9W S33 Kiowa Rainy Mt. Cr. 10/13/92 3m W 5m S Mt. View-S4 T7N R15W S34 Kiowa Sugar Cr. 10/13/92 3m W 5m S Mt. View-S4 T7N R15W S35 Garvin Washita R. 7/7/92 1.5m W Wynnewood(HW 77}-S16 T2N R1E S36 Murray Washita R. 7/7/92 1m W Doughtery-S11 T2S R2E S37 Murray Washita R. 7/7/92 .5m W HW 77-S18 T1S R2E S59 McClain Criner Cr. 6/7/93 5m W HW 74-S34 T5N R3W S60 Garvin Panther Cr. 6/7/93 1m N 2m W Antioch-S7 T3N R2W S61 Garvin Peavine Cr. 6/7/93 5m E HW 77-S2 T3N R1E S62 Garvin Cherokee Sandy Cr. 6/7/93 5m N HW 29-S20 T3N R2E S63 Murray Colbert Cr. 6/14/93 1m W 1-35-S2 T1S R1E S64 Murray Chigley Sandy Cr. 6/14/93 .5m E Chigley-S2 T1N R2E S65 Murray Guy Sandy Cr. 6/14/93 1m N HW 7-S31 T1N R3E Table 3 cant. SITE # COUNTY STREAM DATE LOCATION - LEGALSITE WASHITA RIVER DRAINAGE CONT. S66 Murray Rock Cr. 6/14/93 2m N25m E Sulphur-S26 T1 N R3E S67 Murray Buckhorn Cr. 6/14/93 2m N Drake (HW 177)-S36 T1S R3E S68 Grady Lafline Cr. 6/15/93 1m N 3m E Alex-S9 T5N RW S69 Grady Colbert Cr. 6/15/93 1m N HW 19-536 T5N R5W S70 Grady Little Washita R. 6/15/93 HW 19 bridge-S19 T6N R6W S71 Grady Salt Cr. 6/15/93 2m E HW 81-S20 T8N R7W S72 Kiowa Pecan Cr. 6/17/93 8m N .5m E Saddle Mt.-S17 T6N R14W S73 Kiowa Saddle Mt. Cr. 6/17/93 4m N .75m W Saddle Mt.-S6 T5N R14W S74 Kiowa Sugar Cr. 6/17/93 E bridge on HW 19-521 T5N R15W S75 Carter Hickory Cr. 6/21/93 1m SW Mt. Lake-S27 T2S R1W S76 Carter Coal Cr. 6/21/93 1.75m N HW 53-S6 T3S R3E S77 Carter Wolf Cr. 6/21/93 .25m N HW 199(HW 177)-S24 T4S R3E S78 Carter Henry House Cr. 6/21/93 1m S HW 53-S6 T3S R1E S79 Caddo Spring Cr. 6/22/93 3m S Spring Cr.-S32 T9N R9W S80 Caddo SugarCr. 6/22/93 1m NW Gracemont-S5 T8N R1OW S81 Caddo Sugar Cr. 6/22/93 2m NW Lookeba-S32 T11 N R11W S82 Caddo Delaware Cr. 6/22/93 4m E Anadarko-S17 T7N R9W S83 Washita Gyp Cr. 6/24/93 3m NWCorn-S24 T11N R15W S84 Washita Corn Cr. 6/24/93 3m SW Corn-S18 T10N R15W S85 Washita Boggy Cr. 6/24/93 6m E Cordell-S34 T10N R16W S86 Washita Friendship Cr. 6/24/93 1.5m S HW 54-S9 T9N R15W S87 Johnston Rock Cr. 6/28/93 2m W Tishomingo-S6 T4S R6E S88 Johnston Pennington Cr. 6/28/93 1m NE Reagan-S30 T2S R6E S89 Johnston Butcher Pen Cr. 6/28/93 2m N Bee-S34 T4S R7E S90 Johnston Mill Cr. 6/28/93 1m SW Mill Creek-S13 T2S R4E S91 Marshall Glasses Cr. 6/29/93 ranch land S HW 199-S36 T6S R5E S92 Marshall Little Glasses Cr. 6/29/93 2m NE Kingston-S20 T6S R6E S93 Bryan Newberry Cr. 6/29/93 1.5m NW Mead-S26 T6S R7E S94 Carter Hickory Cr. 7/1/93 2.25m S Wooford-S10 T3S R1W S95 Carter W. Spring Cr. 7/1/93 1.5m NW Milo-S36 T2S R2W S96 Carter Un-named Trib. 7/1/93 2m NE Dickson-S11 T4S R3E S97 Garvin Wildhorse Cr. 7/1/93 .5m E Interstate 35-S27 T1N R1E S98 Custer Turtle Cr. 7/5/93 .5m N Interstate 40-S13 T12N R17W S99 Custer Beaver Cr. 7/5/93 4m N Arapaho-S1 T13N R17W S100 Custer Barnitz Cr. 7/5/93 2.5m NW Clinton-S5 T12N R17W S101 Custer E. Barnitz Cr. 7/5/93 4m NW Arapaho-S19 T13N R17W S102 Roger Mills Sandstone Cr. 7/6/93 .5m HW 283-S4 T11N R23W S103 Custer L. Panther Cr. 7/6/93 1m S HW 73-S2 T12N R20W S104 Roger Mills Rush Cr. 7/6/93 1m N 3m E Reydon-S28 T14N R25W S105 Murray Colbert Cr. 7/8/93 2.25m S HW 7-S15 T1S R1E S106 Garvin Eight-mile Cr. 7/8/93 1m NW Hennepin-S25 T1N ~2W S107 Carter Wildhorse Cr. 7/8/93 3m NE county line-S5 T1S R3W S108 Garvin Sandy Cr. 7/8/93 1m E Katie-S8 T1N R1W 28 S38 Lincoln Deep Fork R. 6/30/92 4m S Chandler(HW18)-S33 T14N R4E S39 Lincoln Deep Fork R. 6/30/92 .25m E of HW 177(@RR bridge)-S17 T14N R3E S40 Oklahoma Deep Fork R. 8/25/92 2.5m N of 1-44(Hiawasse Rd.)-S27 T14N R1W S41 Oklahoma Deep Fork R. 8/25/92 .5m N Luther(Luther Rd.)-S22 T14N R1E S42 Okmulgee Salt Cr. 8/25/92 below Okmulgee L.dam-S8 T13N R12E S43 Coal Muddy Boggy 8/11/92 6m N .5m E Coalgate-S24 T2N R10E S44 Coal Muddy Boggy 8/11/92 3m E 1.5m S Lehigh-S20 T1S R11E S45 Atoka MUddy Boggy 8/11/92 4m E .5m N Bruno-S26 T2s R12E S46 Choctaw Caney Cr. 8/18/92 8m S HW 3-S2 T5S R14E S47 Choctaw Muddy Boggy 8/18/92 1m W 2m S Sandbluff-S22 T5S R14E S48 Choctaw MUddy Boggy 8/18/92 4m S Soper-S2 T7S R15E S49 Payne Cimarron R. 9/15/92 2m SW Ripley(HW 33)-S6 T17N R4E S50 Payne Cimarron R. 9/15/92 4m NW Cushing-S12 T18N R4E S51 Creek Cimarron R. 9/15/92 2m SW Oilton-S8 T18N R7E CHIKASKIA RIVER DRAINAGE S52 Kay Bluff Cr. 7/28/92 2.5m W 1m S HW 177-S20 T29N R2W S53 Kay Chikaskia R. 7/28/92 L. Blackwell dam-S34 T29N R2W S54 Kay Chikaskia R. 7/28/92 at Bluff Cr. mouth(by boat)-S29 T29N R2W S55 Kay Chikaskia R. 7/28/92 .25m W of 1-35-S18 T28N R1W S56 Kay Chikaskia R. 9/1/92 2.5m S 1m E .5m SE HW 177-S18 T25N R1E S57 Kay Chikaskia R. 9/1/92 2.5m E Tonkawa-S1 T25N R1W S58 Kay Chikaskia R. 9/1/92 .5m W HW 177-S9 T27N R1W WASHITA RIVER DRAINAGE (LIMITED SAMPLES) S109 Carter Massey Cr. 8/6/92 NE Pooleville-S14 T1S R2W S110 Washita Gyp Cr. 9/22/92 3m SW Cowden-S36 T9N R15W S111 Custer Oak Cr. 9/22/92 1m SE Foss L. dam-S11 T12N R19W S112 Roger Mills Washita R. 10/6/92 1m S 5m W Hammon-S13 T13N R22W S113 Roger Mills Sandstone Cr. 10/6/92 5m SE Strong City-S23 T13N R22W S114 Roger Mills Washita R. 10/8/92 4m E Reydon-S28 T15N R25W S115 Custer Washita R. 10/8/92 1m E Foss L. dam-S2 T12N R19W 29 Table 4. Summary of variables used in principal components analysis of juvenile flathead catfish from Oklahoma prairie streams, 1992. Description Range Average width (m) 1.5-84.0 Average depth (m) 0.2-1.2 Number of debris piles 0-1 Number of logs 0-4 Current 0-3 Slope 0-1 Shade 0-1 Stability 0-1 Mud 0-3 Clay 0-3 Sand 0-3 Gravel 0-3 Cobble 0-3 Boulders/riprap 0-3 Detritus 0-3 Riffles 0-1 Undercut 0-1 Altitude (m) 135-675 Conductivity 80-3700 Secehi (em) 2-122 Julian date 168-287 Table 5. Summary of flathead catfish collections and observations during electrofishing of Oklahoma prairie streams 1992-93. Total GalJ!11l Total Sialionary Total MOWlg TOlal Qllse O. Fo Length River Number % Total %Total Washita 259 88 Deepfork 71 89 -349 Cimarron 126 88 646 86 (mm) L. River 9 60 MUddy 127 89 Chikaskia 54 68 Washita 16 5 Deepfork 4 5 350-509 Cimarron 5 4 47 6 (mm) L River 1 7 Muddy 8 6 Chikaskia 13 16 Washita 19 7 Deepfork 5 6 510+ Cimarron 12 8 61 8 (mm) L. River 5 33 Muddy 7 5 Chikaskia 13 16 Total 754 Table 7. Length categorization of flathead catfish, collected by electrofishing, from six Oklahoma streams and one Georgia river (Quinn 1991). River electrofishing samples Washita Little MUddy B. Cimarron Deep F. Chikaskia Flint (GA) Size category Length range (mm) (N=21) (N=4) (N=2) (N=8) (N=6) (N=15) (N=1,428) Traditional PSD >510 57 100 0 100 50 40 57 RSD-P >710 19 100 0 12 17 7 11 RSD-M >865 9 50 0 0 17 0 2 RSD-T >1,020 5 25 0 0 0 0 0 Incremental w m RSD S-Q 350-509 43 0 100 0 50 60 43 RSD Q-P 510-709 38 0 0 88 0 33 46 RSD P-M 710-864 9 50 0 12 0 7 9 RSD M-T 865-1,019 5 25 0 0 17 0 2 RSDT >1,020 5 25 0 0 0 0 0 (N=35) (N=6) (N=15) (N=17) (N=9) (N=26) PSD* >510 54 83 47 71 56 54 N = number of flathead catfish collected >350 mm, the minimum stock length (Quinn 1991) PSD = Proportional Stock Density RSD = Relative Stock Density S = stock; Q = quality; P = preferred; M = memorable; T = trophy * = PSD based on flathead catfish collected and observed Table 8. Comparisons of intercept and slope values from simple linear regressions of length (mm) and weight (g) relationships for flathead catfish, from Oklahoma streams (1992-93) and reservoirs (1963,72-73). All regressions are based on the log 10 of total length and weight. Washita 105 -5.139 3.051 0.984 Deep Fork 34 -5.507 3.203 0.989 Cimarron 20 -5.235 3.107 0.993 Little 12 -5.505 3.212 0.996 Muddy Boggy 59 -5.337 3.125 0.985 Chikaskia 35 -5.518 3.200 0.996 1 Statewide (1972-73) Statewide (1963)2 1 = Mense (1976) 2 = Houser and Bross (1963) Table 9. Reach intercept and slope values from simple linear regressions of length (mm) and weight (g) relationships from Oklahoma streams, 1992-93. All regressions are based on the log 10 of total length and weight. 2 Location* N Intercept Slope r WA-Ver/E12 6 -2.780 1.946 0.073 WA-ChilE13 2 -5.436 3.197 WA-PauIE14 4 -5.070 3.001 0.752 WA-Wyn/E15 2 -4.425 2.754 WA-Dou/E16 3 -5.155 3.045 0.963 WA-ManIE17 7 -5.358 3.116 0.985 WA-TislE18 9 -4.680 2.866 0.987 WA-ChiIE 13a 20 -5.097 3.047 0.978 WA-E18a 49 -5.261 3.095 0.995 WA-E13b 2 -5.934 3.345 DF-ChalE9 3 -3.165 2.217 0.982 DF-Ofu/E11 31 -5.700 3.277 0.995 CI-OiIlE8 20 -5.235 3.107 0.993 LR-Thu/E7 12 -5.505 3.212 0.996 MB-LehIE4 9 -5.365 3.137 0.989 MB-Bru/E5 34 -5.399 3.150 0.979 MB-GayIE6 16 -5.129 3.038 0.994 CH-Abo/E1 10 -5.282 3.113 0.992 CH-BeI/E2 16 -5.610 3.229 0.997 CH-Ton/E3 9 -5.378 3.152 0.996 * = See Table 1 for location description ** = Sample size too small 38 Table 10. Analysis of relative weight for flathead catfish collected from Oklahoma prairie streams during 1992-93 electrofishing. River Len(mm) W mean W Num indiv River Len(mm) W mean W Num indiv r r r r Washita 281 85 87 3 Cimarron 319 81 81 1 293 89 324 89 85 2 295 87 335 80 306 83 80 3 422 86 86 1 314 78 575 105 105 1 315 80 580 105 105 1 320 75 82 5 603 104 104 1 320 95 630 118 118 1 325 79 640 103 103 1 331 80 679 110 110 1 333 80 715 104 104 1 343 77 77 1 L. River 305 92 92 1 372 78 78 1 730 102 102 1 402 88 88 1 753 115 115 1 425 80 83 4 920 100 100 1 425 85 1100 110 110 1 428 83 M. Boggy 292 83 88 2 432 84 294 93 440 87 87 1 302 80 83 3 466 86 86 1 305 83 501 86 86 2 318 86 510 87 328 88 88 1 520 79 85 3 406 84 84 1 525 77 440 92 92 1 530 98 Chikaskia 282 88 89 1 545 82 82 1 300 83 84 2 565 90 89 2 311 85 570 89 321 86 86 1 580 91 91 1 345 82 85 4 691 104 104 1 347 95 730 95 95 1 350 81 820 102 102 1 355 83 880 99 99 1 366 79 79 1 925 101 99 2 399 87 87 1 930 97 435 100 100 1 1100 116 116 1 455 90 90 1 D. Fork 283 83 83 1 474 85 85 1 301 89 87 4 490 98 95 2 305 76 491 92 310 84 525 92 92 1 317 101 590 86 86 1 347 85 84 1 645 94 96 3 355 83 83 1 650 97 410 95 95 1 655 97 473 94 94 1 860 109 109 1 595 105 105 1 638 101 101 1 930 120 120 1 Table 11. Statewide relative weight of flathead catfish collected from Oklahoma prairie streams during 1992-93 electrofishing. Length group Mean Wr Num Indiv Length group Mean Wr Num Indiv (mm) (mm) 280-299 87 7 580-599 97 4 300-319 84 14 600-619 104 1 320-339 84 9 620-639 109 2 340-359 84 7 640-659 98 4 360-379 79 2 660-679 110 380-399 87 680-699 104 1 400-419 89 3 700-719 104 1 420-439 86 6 720-739 99 2 440-459 90 3 740-759 115 1 460-479 88 3 820-839 102 1 480-499 95 2 860-879 109 1 500-519 87 2 880-899 99 1 520-539 87 4 920-939 105 4 540-559 82 1 1100-1119 113 2 560-579 95 3 Table 12. Location and abundance of species collected/observed during 1992-93 electrofishing from Oklahoma prairie streams. LOCATION· SPECIES E1 E2 E3 E4 E5 E6 E7 E8 E9 E10 E11 FLATHEAD CATFISH 18 29 33 44 70 28 15 143 6 6 68 BLUE CATFISH 4 13 19 12 26 CHANNEL CATFISH 3 3 2 116 2 3 FRECKLED MADTOM 2 GIZZARD SHAD 116 30 20 14 185 12 10 7 7 GOLDEYE COMMON CARP 3 9 23 1 3 2 22 5 25 2 21 GRASS CARP SMALLMOUTH BUFFALO 1 7 5 1 9 5 19 BIGMOUTH BUFFALO 23 BLACK BUFFALO 1 BUFFALO SPP. 15 RIVER CARPSUCKER 9 2 12 1 1 11 2 GOLDEN REDHORSE 1 BLUE SUCKER 1 LONGNOSE GAR 2 33 6 1 5 1 SHORTNOSE GAR 1 10 SPOTTED GAR 1 FRESHWATER DRUM 1 1 2 WHITE BASS 1 LARGEMOUTH BASS 3 2 WHITE CRAPPIE 14 2 1 1 1 3 14 GREEN SUNFISH ORANGESPOTTED SUNFISH 1 BLUEGILL 1 LONGEAR SUNFISH 3 3 SILVER CHUB LOCATION· SPECIES E12 E13 El3a E 13b E14 E15 E16 E17 E18 E18a TOTAL FLATHEAD CATFISH 13 6 98 4 9 4 14 17 26 107 758 BlUE CATFISH 2 4 4 1 2 23 12 27 40 118 307 CHANNEL CATFISH 1 1 3 1 7 14 156 FRECKLED MADTOM 2 GIZZARD SHAD 3 16 15 6 441 GOLDEYE 5 5 COMMON CARP 6 2 4 21 2 11 3 165 GRASS CARP 1 3 4 SMALLMOUTH BUFFALO 7 12 7 18 2 8 1 2 2 106 BIGMOUTH BUFFALO 4 2 1 30 BLACK BUFFALO 1 BUFFALO SPP. 15 RIVER CARPSUCKER 1 1 6 248 5 1 300 GOLDEN REDHORSE 1 BLUE SUCKER 1 LONGNOSE GAR 7 11 7 3 1 10 2 89 SHORTNOSE GAR 1 12 SPOTTED GAR 1 FRESHWATER DRUM 5 4 13 WHITE BASS 2 3 lARGEMOUTH BASS 1 6 WHITE CRAPPIE 2 38 GREEN SUNFISH 1 1 ORANGESPOTTED SUNFISH 1 BLUEGILL 1 LONGEAR SUNFISH 6 SILVER CHUB 2 2 Table 13 • Principal component loadings for 21 variables included in habitat analysis of juvenile flathead catfish in Oklahoma prairie stream systems, 1992. Parenthesis indicate percent variance accounted for by each axis. Asterisks indicate loadings greater than 0.40. Width -0.72 * -0.50 * 0.00 -0.14 Secchi 0.67* 0.23 0.18 -0.19 Gravel 0.66* -0.32 0.06 -0.14 Riffles 0.66* 0.11 -0.05 -0.17 Undercut 0.64* 0.21 -0.29 -0.06 Cobble 0.57* -0.44 * -0.22 -0.29 Shade 0.56* 0.03 -0.44 * 0.06 Altitude -0.04 0.88 * -0.18 0.11 Conductivity -0.38 0.74* 0.01 0.06 Depth -0.40 * -0.65 * -0.36 0.17 Sand -0.30 0.13 0.60* -0.41 * Slope -0.14 0.04 -0.55 * -0.12 Logs 0.02 -0.42 * 0.52* 0.24 Clay 0.37 0.01 0.24 0.71 * Mud -0.15 -0.34 -0.36 0.53* Detritus 0.44* -0.27 0.06 0.42* Debris piles -0.16 0.11 0.04 0.33 Days 0.49* 0.18 0.48* 0.28 Sould/rip 0.36 -0.49 * 0.07 -0.26 Stability 0.47* 0.36 -0.22 0.04 Current 0.41 * -0.39 0.14 -0.04 Table 14. Location and abundance of species collected by seine during 1992-93, from 108 stream sites in Oklahoma. SITE' SPECIES S1 S2 S3 S4 S5 S6 S7 S8 S9 S10 S11 S12 SPOTTED GAR LONGNOSE GAR 2 1 SHORTNOSE GAR GIZZARD SHAD 15 2 2 5 7 1 THREAOFIN SHAD GRASS PICKEREL CENTRAL STONEROLLER 43 1 4 COMMON CARP 4 1 3 SILVERY MINNOW PLAINS MINNOW 1 1 SPEO SITE * SPECIES S109 S110 S111 S112 S113 S114 S115 CENTRALSTONEROLLER 4 10 X RED SHINER X 116 X X X SAND SHINER X 34 SUCKERMOUTH MINNOW X X BULLHEAD MINNOW 19 3 X YELLOW BULLHEAD 4 FLATHEAD CATFISH 1 1 1 PLAINS KILLIFISH 33 MOSQUITOFISH 1 X 30 GREEN SUNFISH 2 X 1 BLUEGILL 2 LARGEMOUTH BASS X ORANGETHROAT DARTER 15 5 X 20 DUSKY DARTER 3 Table 16. Comparisons of estimated length-weight relationships for flathead catfish from Oklahoma streams (1992-93) and reservoirs (1963 and 1972-73). Length Weight (g) Length Weight (g) Length Weight (g) (mm) 1992-93 1972-73a 1963b (mm) 1992-93 1972-73a 1963b (mm) 1992-93 1972-73a 1963b 100 8.55 8.28 7.66 420 756.89 712.14 817.86 740 444099 4131.38 5168.32 105 9.96 9.63 8.97 425 785.39 738.79 849.97 745 4535.41 4218.65 5282.85 110 11.52 11.13 10.44 430 814.62 766.10 882.96 750 4631.18 4307.15 5399.14 115 13.23 12.78 12.07 435 844.58 794.09 916.82 755 4728.31 4396.91 5517.18 120 15.11 14.58 13.86 440 875.28 822.77 951.57 760 4826.83 4487.92 5637.00 125 17.17 16.55 15.83 445 906.73 852.14 987.22 765 4926.73 4580.21 5758.61 130 19.41 18.69 17.98 450 938.94 882.21 1023.78 770 5028.02 4673.77 5882.03 135 21.84 21.02 20.33 455 971.91 912.99 1061.27 775 5130.72 4768.62 6007.27 140 2446 23.53 22.89 460 1005.67 944.50 1099.71 780 5234.84 4864.76 6134.34 145 27.30 26.24 25.66 465 1040.21 976.73 1139.09 785 5340.39 4962.21 6263.26 150 30.35 29.15 28.65 470 1075.56 1009.70 1179.45 790 5447.37 5060.98 6394.05 155 33.62 32.27 31.88 475 1111.71 1043.41 1220.78 795 5555.80 5161.07 6526.72 160 37.13 35.61 35.35 480 1148.68 1077.89 1263.11 800 5665.69 5262.49 6661.28 165 40.87 39.18 39.08 485 1186.47 1113.12 1306.44 805 5777.05 5365.26 6797.76 170 44.87 4298 43.06 490 1225.10 1149.13 1350.79 810 5889.89 5469.37 6936.15 175 49.12 47.03 4732 495 1264.58 1185.92 1396.18 815 6004.22 5574.85 7076.49 180 53.64 51.33 51.87 500 1304.92 1223.50 1442.60 820 6120.04 5681.70 7218.78 185 58.43 5589 56.71 505 1346.12 1261.88 1490.09 825 6237.38 5789.93 7363.05 190 63.51 60.71 61.85 510 1388.19 1301.06 1538.65 830 635624 5899.54 7509.30 195 68.88 65.81 67.31 515 1431.15 1341.06 1588.30 835 6476.62 6010.56 7657.54 200 74.54 71.19 7309 520 1475.01 1381.89 1639.05 840 6598.55 612298 7807.81 205 80.52 76.86 79.21 525 1519.77 1423.56 1690.90 845 6722.03 6236.82 7960.10 210 86.82 82.83 85.67 530 1565.45 1466.06 1743.89 850 6847.07 6352.09 8114.44 215 93.44 89.10 92.49 535 1612.05 1509.42 1798.01 855 6973.68 6468.79 8270.84 220 100.40 95.69 99.67 540 1659.58 1553.64 1853.28 860 7101.88 6586.93 8429.32 225 107.70 102.61 107.24 545 1708.06 1598.73 1909.72 865 7231.67 6706.53 8589.89 230 115.36 109.85 115.19 550 1757.49 1644.70 1967.35 870 7363.06 6827.60 8752.56 235 123.37 117.43 123.55 555 1807.89 1691.55 2026.16 875 7496.06 6950.13 8917.36 240 131.76 125.36 132.31 560 1859.26 1739.30 2086.18 880 7630.69 7074.15 9084.29 245 140.53 133.65 141.49 565 1911.61 1787.96 2147.42 885 7766.95 7199.66 9253.38 250 149.68 142.30 151.11 570 1964.96 1837.53 2209.90 890 7904.86 7326.67 9424.63 255 159.23 151.32 161.17 575 2019.31 1888.03 2273.62 895 8044.43 7455.19 9598.07 260 169.19 160.72 171.69 580 2074.67 1939.46 2338.61 900 8185.66 7585.23 9773.71 265 179.56 170.51 182.67 585 2131.06 1991.83 2404.87 905 8328.56 7716.80 9951.56 270 190.36 180.70 194.13 590 2188.48 2045.15 2472.43 910 8473.16 7849.91 10131.64 275 201.59 191.29 206.08 595 2246.94 2099.43 2541.28 915 8619.45 7984.56 10313.97 280 213.27 202.29 218.52 600 2306.45 2154.67 2611.45 920 8767.45 8120.77 10498.55 285 225.39 213.72 231.48 605 2367.03 2210.90 2682.96 925 8917.16 8258.55 10685.41 290 237.98 225.57 244.97 610 2428.68 2268.11 2755.81 930 9068.61 8397.91 10874.57 295 251.03 237.86 258.98 615 2491.41 2326.31 2830.01 935 9221.80 8538.85 11066.03 300 264.56 250.60 273.55 620 2555.24 2385.52 2905.59 940 9376.73 8681.38 11259.81 305 278.58 263.80 288.67 625 2620.17 2445.75 2982.56 945 9533.43 8825.52 11455.93 310 293.10 277.45 304.36 630 2686.21 2506.99 3060.93 950 9691.89 8971.27 11654.41 315 308.12 291.58 320.63 635 2753.37 2569.27 3140.71 955 9852.14 9118.65 11855.26 320 323.66 306.19 337.49 640 2821.67 2632.59 3221.93 960 10014.18 9267.66 12058.49 325 339.72 321.28 354.96 645 2891.11 2696.95 3304.58 965 10178.02 9418.31 12264.12 330 356.32 336.87 373.05 650 2961.70 2762.38 3388.70 970 10343.68 9570.61 12472.17 335 373.46 352.97 391.76 655 3033.46 2828.87 3474.28 975 10511.15 9724.57 12682.65 340 391.15 369.58 411.12 660 3106.38 2896.44 3561.36 980 10680.47 9880.20 12895.58 345 409.40 386.71 431.12 665 3180.50 2965.09 3649.93 985 10851.63 10037.51 13110.97 350 428.22 404.38 451.80 670 3255.80 3034.84 3740.02 990 11024.64 10196.51 13328.85 355 447.62 422.58 473.14 675 3332.31 3105.70 3831.63 995 11199.5210357.21 13549.21 360 467.62 441.33 495.18 680 3410.03 3177.66 3924.79 1000 11376.27 10519.62 13772.09 365 488.21 460.64 517.92 685 3488.97 3250.75 4019.51 370 509.40 480.51 541.37 690 3569.15 3324.97 4115.80 1010 11735.46 10849.60 14225.45 375 531.22 500.95 565.55 695 3650.57 3400.33 4213.67 1020 12102.2711186.5214689.04 380 553.66 521.97 590.47 700 3733.24 3476.84 4313.15 1030 12476.81 11530.46 15163.00 385 576.74 543.59 616.13 705 3817.18 3554.50 4414.24 1040 12859.1511881.51 15647.45 390 600.46 565.80 642.56 710 3902.39 3633.34 4516.96 1050 13249.37 12239.72 16142.51 395 624.84 588.62 669.77 715 3988.89 3713.35 4621.32 1060 13647.58 12605.19 16648.33 400 649.88 612.06 697.76 720 4076.68 3794.55 4727.34 1070 14053.84 12977.98 17165.02 405 675.60 636.12 726.55 725 4165.78 3876.94 4835.04 1080 14468.24 13358.18 17692.71 410 702.00 660.82 756.16 730 4256.19 3960.54 4944.43 1090 14890.88 13745.86 18231.54 415 729.09 686.15 786.59 735 4347.92 4045.35 5055.51 1100 15321.83 14141.09 18781.63 Table 17. Observations of angler activity from selected Oklahoma stream locations, 1992-93. BANK/LIMB BANK BOATS LOCATION * LINES ANGLERS (PERSONS) BARRELS E1 4 1 (2) E2 4 E3 2 E4 E5 E6 18 2 E7 23 E8 17 3 E9 12 2 also 6/30/92 4 1 (2) E10 8 E11 12 E12 3 2 also 5/19/92 5 E13 10 5 1 (1) also 6/18/92 12 E13a 30 6 E 13b 3 5 E14 30 E15 5 1 E16 11 E17 5 2 E18 11 2 E18a 16 2 * = See Table 1 for location description 55 Table 18. Available angler access for selected Oklahoma stream sites. SITES % ACCESS FOR % ACCESS FOR VIEWED BANK ANGLERS LIGHT BOATS 100 90 N = 294 N = 80 N = 143 80 (f) z 0- 70 N = 80 .«- >a: w 60 (f) (1) 0 50 LL 0 40 .z- w 0 a: 30 cw.. 20 10 STREAMS ELECTROFISHED 1_-349 mm [2J3S0-S09 mm []S10+ mm I 57 Figure 2. Presence/absence of Oklahoma juvenile flathead catfish arrayed on PC 1 and PC 2, 1992. • Absent x Present • •• x • • x • x • x • x • •• • x • • x . ., • • w • ./. A a: • • • OCIJ • ·x ~ffi • ·x • w0:-J0 x • w:J X- x 0 x 0.co x • Ww x Oa: -0 ~- ~ ci w· • x x Z-J • OCO OCO ~8 x • Ow -Ja: ~o «-J~ . ~~ x 00-J-J DEEp, WIDE, LESS GRAVEL, LESS SHALLOW, NARROW, MORE GRAVEL, COBBLE, LESS UNDERCUT, LESS MORE COBBLE, MORE UNDERCUT, DETRITUS, SLOWER, EARLIER, MORE MORE DETRITUS, SWIFTER, LATER, TURBID LESS TURBID, RIFFLES, SHADED, STABLE Figure 3. Micro-habitat associations of Oklahoma juvenile flathead catfish, 1992-93. N = 55 Rock 58% Flow 96% Other on-flow 6% 4% Rock/Wood 4% Wood 32% Figure 4. Comparisons of length-weight relationships for flathead catfish collected from Oklahoma streams (1992-93) and reservoirs (1963 and 1976). I I I I I I, I",I I" 1'1 I .' I, ,/ I .' I ,'1 I .'1 S 10000 - '1"-4 I '1" ~ I", ' I ,/ I" / .:/, I ,', / " /. :1, I ,/ I ~. I ,: I" I" #'" •• .'l , /.'/ /. .' /..1'/."." .tI!.~,:JI' " ~,tJI".,P~ I 600 LENGTH (mm)