Relative abundance, movements, and habitat use of southeastern blue sucker cycleptus meridionalis in the lower Pearl River, Louisiana.
Catostomidae is a moderately diverse family (70 species in the U.S.; Nelson et al., 2004) of lacustrine and riverine fishes distributed widely throughout North America (Lee et al., 1980; Scott and Crossman, 1998). Although Catostomidae fishes can dominate abundance and biomass of lake and river fish assemblages (e.g., Bertolo et al., 2005; Weigel et al., 2006), most species are characterized by limited recreational and commercial value, a paucity of life history information, and a lack of public awareness and funding to support increased research and management efforts (Cooke et al., 2005). Recently, catostomidae fishes have become the subject of considerable conservation concern because of widespread population declines for both lacustrine (e.g., Lost River sucker Deltistes luxatus and short-nose sucker Chasmistes brevirostris, Banish et al., 2009; Rasmussen, 2011) and riverine species (e.g., modoc sucker Catostomus microps, Smith et al., 2011; robust redhorse Moxostoma robustum Peterson et al., 2013). Ten Catostomidae fishes are currently listed as threatened or endangered in the U.S. (see http://ecos.fws.gov/ecos/home.action) and many additional species are listed at state levels throughout some or all of their current ranges (e.g., Vokoun et al., 2003; Compton et al., 2008; Grabowski and Jennings, 2009; Reid, 2009).
Numerous environmental factors have been implicated in the decline of catostomidae populations across the U.S., including harvest and larval entrainment (Rasmussen, 2011), hybridization, predation, and competition with introduced taxa (Compton et al., 2008; McDonald et al., 2008; Schultz and Bertrand, 2012), and elevated river discharge during the spawning and rearing period (Peterson et al., 2013). For most riverine taxa, however, the effects of dams and diversions on habitat availability and suitability (Cooke et al., 2005), loss of riverine and river-tributary connectivity and population fragmentation (e.g., Compton et al., 2008; Rasmussen, 2011), and disruption of spawning migrations (Tyus and Karp, 1990; McKinney et al., 1999; Cooperman and Markle, 2003; Mettee et al., 2004) are widely cited as significant contributors to sucker population declines. In the southeastern U.S., construction of dams and sills poses a dominant threat to catostomids (Douglas and Jordan, 2002; Cooke et al., 2005) from reductions in habitat quality related to alteration of river hydrology and substrate composition (Yoder and Beaumier, 1986; Graf, 1999; Cooke et al., 2005; Adams et al., 2006; Grabowski and Isely, 2007).
The southeastern blue sucker Cycleptus meridionalis is a moderately large riverine fish in the Catostomidae family that was recently separated taxonomically from the blue sucker C. elongatus by Burr and Mayden (1999). Southeastern blue sucker and blue sucker habitat preferences appear to be similar with both species inhabiting swift main channel habitats with increased catches of southeastern blue suckers around large accumulations of woody debris over gravel substrates (Peterson et al., 1999, 2000; Neely et al. 2010). The southeastern blue sucker, is confined geographically to the Pearl, Pascagoula, and Alabama River systems (Peterson et al., 1999, 2000; Ross, 2001; Mettee et al., 2004) and has declined in abundance in recent decades. This decline is similar to that exhibited by the blue sucker, which was a historically abundant and commercially important species in the upper Mississippi River, but declined in abundance after the early 1900's with increasing modification of river flows (Coker, 1930; Burr and Mayden, 1999). Similar to many imperiled catostomids that have suffered from degradation and loss of riverine habitat (Yoder and Beaumier, 1986; Cooke et al., 2005; Grabowski and Isely, 2007; Reid et al., 2008), the southeastern blue sucker is imperiled throughout much of its range and is listed as a species of concern in Louisiana (Bart and Rios, 2003; Kelso et al., 2008) and Mississippi (Ross, 2001), with a global ranking of G3/G4 (vulnerable or apparently secure; Bart and Rios, 2003). Moreover, the Louisiana Department of Wildlife and Fisheries has elevated concern over diminishing populations to the highest state level of conservation concern (SI ranking; Holcomb et al., 2015).
The Alabama River population of southeastern blue sucker has been estimated to range from 773 to 1275 individuals (Mettee et al., 2004). Although a seemingly small population size given the extent of the Alabama River system, Mettee et al. (2004) considered the population to be stable. These fish exhibited an affinity for woody debris and often returned to the same submerged tree top in successive years, suggesting high habitat specificity (Mettee et al., 2004). This population also exhibited an extended seasonal migration, with some individuals traveling 496 km upriver past dams and other river modifications to spawn. Neely et al. (2009) described similar large movements and high site fidelity for blue suckers in the Missouri River. Conversely, Peterson et al. (2000) reported minimal (<3.2 km) summer movements of a tagged southeastern blue sucker in the middle Pearl River, the portion of the river in Mississippi just before it enters Louisiana, and suggested movements of these fish may have been impeded by anthropogenic river modifications. Although unable to produce viable population estimates (56 marked individuals, only one recapture) Peterson et al. (1999, 2000) also concluded the southeastern blue sucker population was healthy in this section of the river.
In contrast to Peterson et al. (1999, 2000), who were able to collect 263 southeastern blue suckers in their study, electrofishing surveys in the lower Pearl River (Louisiana) have historically produced few individuals (e.g., n = 10 in three extensive lower Pearl River electrofishing samples in 2012; W.E. Kelso and M.D. Kaller, unpubl.). Previous studies of long-term changes in the lower Pearl River ichthyofauna (e.g., Gunning and Suttkus, 1991; Geheber and Piller, 2012) were based on seining of shallow sand bars, which is habitat that has not been associated with southeastern blue suckers (Mettee et al., 2004). No study has targeted habitat use, movement patterns, and abundance of southeastern blue sucker in the Louisiana section of the Pearl River. Because of the apparent scarcity of southeastern blue suckers in this highly altered section of the river, as well as a lack of basic life history information for these fish, our study addressed the following objectives: (1) assess the relative abundance of southeastern blue suckers in the benthic fish assemblage based on a boat-electrofishing survey of deeper water habitats; (2) determine habitat associations and movements of radio-tagged individuals; and (3) quantify and model habitat characteristics at southeastern blue sucker locations based on detailed bathymetry and habitat mapping of the lower Pearl River.
The Pearl River, that runs through Mississippi and Louisiana, is the largest of the three rivers inhabited by the southeastern blue sucker and has been subject to substantial flow modifications from a mainstem dam, low-head sill, and a navigation channel with multiple closed locks. Furthermore, increased sedimentation and water quality issues related to variously modified discharges from agricultural, industrial, urban, and developed riparian sources have also impacted the river. Suckers inhabiting the lower portion of the river have also experienced several hurricanes, tropical storms, floods, and a pulp-mill effluent fish kill over the last decade. Although variability in flow velocity resulting from discharge fluctuations through Ross Barnett dam influences hydrology throughout the river, alteration of sucker habitat from the low-head sill, as well as a high flow slough and navigation channel are confined primarily to the lower Pearl (Louisiana section) of the river. It is likely the pervasive habitat modifications in the Pearl River have been responsible for the apparent decline of southeastern blue sucker in this system (Peterson et al, 1999, 2000; Mettee et al., 2004; Santucci Jr. et al., 2005; Kelso et al., 2008).
Peterson et al. (2000) reported southeastern blue sucker catch per unit effort (CPUE) was highest in the summer and fall when water levels were low. Consequently, sampling was conducted in the main branch of the Pearl River from July 2010 to October 2010 (main branch; n = 22 sample sites), and the west branch of the river in July 2010 and July 2011 (west branch; n = 13 sample sites) (Fig. 1) both in Louisiana. Southeastern blue suckers and other large benthic fishes were collected via electrofishing (720-1000 volts, 8-8.5 amps) for periods ranging from 15 to 30 min (depending on the extent of suitable habitat; i.e., some sample sites were too big to sample in 15 min), with most of the effort focused in high current areas near woody debris (Peterson et al, 1999; Mettee et al, 2004). Captured southeastern blue suckers were measured [mm total length (TL)], fin clipped (left pectoral) and marked just below the eye with VI alpha tags (Northwest Marine Technologies), and released; no mortality of fish during sampling was noted. All other sampled fishes were recorded but not measured, clipped, or marked. All fish were handled in accordance with Institutional Animal Care and Use protocols (A2012-02 and previous).
Overall fish abundance was expressed as number of fish per min of power-on fishing time, and these data were analyzed with a generalized linear mixed model, nesting species within river section (main branch or west branch). Individual species CPUEs were analyzed with PROC GLIMMIX (SAS version 9.3, Cary, North Carolina) based on the normal distribution, with an identity link with a random effect of sample site. Tukey's post-hoc pair-wise tests were used ([alpha] = 0.05) to compare differences in fish abundance between the main branch and the west branch of the river, as well as between southeastern blue suckers and six other large benthic species inhabiting the two branches of the river. All assumptions for the use of a linear model and normal distribution were assessed and met. Based on mark-recapture data collected from summer 2010 through spring 2012, estimation of the size of the southeastern blue sucker population for this portion of the river was attempted with a Jolly-Seber model (Jolly, 1965; Seber, 1965; Mettee et al., 2004) and a state space model (Bolker, 2008).
MOVEMENT AND HABITAT SELECTION
Prior to initiation of the telemetry study, detection capabilities of the tracking system used in this study were investigated with a Lotek SRX 400 receiver fitted with a three-element folding Yagi antennae (Lotek Wireless Inc., Newmarket, Ontario). Tags were lowered in the river in 0.15 m increments and moving away from the tag location at 1 m intervals. The furthest distance a tag could be detected was 32 m when the tag was at a depth of 4 m. Based on these results, deeper and/or wider areas required that the boat move from side to side in a zigzag pattern to make sure all potential habitats were covered.
Radio tags were attached externally (ATS[R] Model F1970, 4.3 g, 440 d battery life, <3% body weight; Advanced Telemetry Systems, Isand, MN) to the base of the dorsal fin of six southeastern blue suckers in August-September of 2011 and five additional fish in March of 2012 (tag frequencies ranged from 164.201 to 165.707; LSU AgCenter IACUC No. A2012-02 and previous). Tags were externally attached to minimize effects on growth, mortality, and breeding behavior; studies have shown tags < 3% of body weight have minimal impacts on fish behavior, growth rates, and mortality rates compared to internally mounted tags and may not differ from untagged control's (Tyus, 1988; Cooke, 2003; Okland et al, 2003; Rogers and White, 2007). Fish were tracked from the tagging date until the first week of July 2012 and were located approximately weekly during diurnal tracking, as well as during two nocturnal tracking periods, unless sites/boat ramps were not accessible due to low or high water.
During tracking, the entire river section of interest was traversed while scanning for tag signals. When signals were detected, the location was noted and defined as a tracking point. At each tracking point, season (spring, summer, fall, winter), time of day (24 h), date, GPS location (UTM), and presence (1) or absence (0) of woody debris were recorded, and dissolved oxygen (mg/L), turbidity (NTU), temperature (C), specific conductance (mScm1), pH, and velocity (m/s) were measured with a YSI[R] 650 MDS multimeter datasonde and a Sontek FlowTracker handheld ADV (YSI Inc., Yellow Springs, OH). Depth (m) at each location was extracted from a bathymetric map that was developed for the river during this study (see River Mapping section). Fish locations were revisited in June 2012 and the presence (1) or absence (0) of gravel substrate were recorded with a Hummingbird[R] 1198C side-scan sonar unit (Johnson Outdoors Marine Electronics Inc., Eufaula, AL; Kaeser and Litts, 2008, 2010; Kaeser et al, 2013). River bends were subdivided into northern half outside, northern half inside, southern half outside, and southern half inside to describe more accurately habitat use by tagged fish within a bend and to be consistent with U.S. Fish and Wildlife Service and Louisiana Department of Natural Resources habitat delineations. Each location was assigned to one of these categories. Northern half bends of the Pearl River were typically characterized by larger woody debris, faster currents, and more gravel than sand/gravel mix relative to the southern half of bends. Inside bends were split from outside bends because they typically had slower currents and finer substrate particles compared to outside bends.
Two standard deviation ellipses (approximating the 95% confidence limits; Wong and Lee, 2005) were predicted to estimate home ranges from marked GPS points for each fish with Crimestat 3 (National Institute of Justice, Washington D.C.). Home ranges were clipped manually in ArcMap to remove potential locations outside the bounds of the river following Hodder et al. (2007). Home range was measured in linear distances in ArcMap in river kilometers, which approximated the 95% confidence limit for total linear distance traveled by the fish.
In order to estimate fish location depths and model the probabilities of finding southeastern blue suckers at a given location, a single beam Eagle[R] Fish Elite 642C (Eagle Electronics, Catoosa, OK) recording sonar unit was used to conduct a traverse bathymetric survey (Hankin, 1984; Hankin and Reeves, 1988; McMahon et al., 1996) of the lower Pearl River in summer 2010 and fall 2011. Briefly, the boat was moved upstream at a speed of approximately 12 kph in a straight line (as much as possible given the irregularity of the shoreline) between the midpoints of consecutive outside bends, continuing successively to upstream bends, such that a zigzag pattern of bank-to-bank transects produced a network of depth points within the channel. Subsequently, depths across the width of the river between the bank-to-bank transects were interpolated using inverse density weighting methodology (ArcGIS[R] 9.3). With this unit a 116.6 km bathymetric map of the lower Pearl River was produced in 24 operating hours, with depth measurements accurate to 0.03 m.
MODEL PREDICTIONS OF HABITAT USE
A generalized linear mixed model was used (PROC GLIMMIX, SAS version 9.3, Cary, North Carolina) to predict the probability of finding a southeastern blue sucker at a given site based on the water quality and habitat variables measured at each fish biotelemetry location. The model incorporated a beta distribution and a logit link, which was the only combination of eight examined combinations of canonical and noncanonical links (e.g., logit, inverse, log, etc.) and distributions (e.g., binomial, negative binomial, beta, etc.) that satisfied the combined goodness of fit criteria of lowest AIC and a Generalized Chi-Square/ Degree of freedom closest to one, with no nonsignificant effects in the model. Seven continuous fixed effect variables (dissolved oxygen, turbidity, temperature, specific conductance, pH, velocity, time of day, and depth), two categorical random effects (date, seasons) and two discrete fixed effect variables (gravel and woody debris) were tested in the model. Importantly, depth in the model was based on the interpolated river map adjusted by river stage for analytical convenience. The response was expressed as a proportion of the number of locations for a specific fish at a given site divided by the total number of observed locations at all sites for that fish. This model produced probabilities of finding a southeastern blue sucker given the measured habitat variables. Southeastern blue sucker locations with confidence limit bounds greater than 50% predicted probability and the highest predicted probabilities (given the confidence limit bounds) of finding a fish were considered habitat selected for or associated with southeastern blue suckers.
SOUTHEASTERN BLUE SUCKER ABUNDANCE
Electrofishing surveys in the west and main branches of the Pearl River yielded 17 southeastern blue sucker, as well as 22 blacktail redhorse Moxostoma poecilurum, 37 quillback Carpiodes cyprinus, 47 highfin carpsucker C. velifer, 347 smallmouth buffalo Ictiobus bubalus, 297 channel catfish Ictalurus punctatus, and 262 flathead catfish Pylodictus olivaris. Overall CPUE of these seven species was higher in the main branch (1.97 fish/min) than in the west branch (1.01 fish/min) of the river (P = 0.03), although there were no significant differences in CPUE between the two branches of the river for any of the seven species individually (CPUE = 0 to 0.66, all P > 0.16). Within the two branches of the river, smallmouth buffalo and the two catfishes were the most abundant species, with relatively low catch rates for the other four catostomids (Table 1). A total of 26 southeastern blue suckers were marked during the course of the study (nine fish were collected after the survey work), but only three individuals were recaptured, which was inadequate for calculating a viable population estimate for this section of the river. All recaptured individuals were found near their tagging area (<10 km for two fish and <1 km the other individual) after periods of at least 1 y.
MOVEMENT AND HABITAT SELECTION
All tagged southeastern blue suckers were located during every location attempt (n = 204, total number of detections) except fish 4, which was never found after its 3rd relocation (Table 2). During nocturnal tracking, three fish with eight locations each were tracked the first night and two fish with eight locations each on a second night (five fish, a total of 40 locations). Movements were minimal, with most fish spending months in a single bend, and often not moving more than a ~12 m from where they were located the prior week. Fish never traveled more than three river bends(<3 km) beyond where they were initially tagged. Fish that moved from one bend to another either re-established position in the new bend, or stayed there for an extended period of time before moving again. Fish 1 had the largest home range (3.8 km), fish 7 had the smallest (0.30 km), and fish 3 and fish 6 established more than one home range during the study (Table 2).
Predictive habitat models were evaluated using first-order autoregressive (AR1), unstructured (UN); as well as the default covariance structure (variance components) with generalized linear mixed models. Within these models, all fish locations were combined (n = 204) given the fish exhibited similar behavior during the duration of this study (Rogers and White, 2007). Individual fish identities were preserved as the sampling unit by designating individual fish as the subject within the random effect covariance matrix (Zuur et al, 2009; Kery and Royle, 2016). The default covariance structure produced the best fitting models with only significant variables left in the model (Table 3). Based on goodness of fit criteria (AIC = -41.53, Generalized Chi-Square/DF = 1.10) the best model predicting the probability of finding a southeastern blue sucker at a given location (P) was:
p = log [e.sup.[eta]] / 1 - [e.sup.[eta]], where [eta] = -2.44 (intercept; SE 0.61; P = 0.0001) + 0.88 (wood; se 0.40; P = 0.0287) + 0.45 (depth; se 0.10; P < 0.0001) + 0.98 (gravel; SE 0.46; P = 0.0356) - 0.032 (temp; SE 0.01; P = 0.009).
These results indicate habitats characterized by a combination of greater depth, gravel substrates, and woody debris with lower water temperatures increased the probability of finding a southeastern blue sucker at a given location; whereas the lack of any of these habitat components at a location (particularly gravel and woody debris) generally decreased the probability of finding a fish. Sites that were deep ([greater than or equal to] 3.7 m) with both gravel substrates and woody debris present had the highest probabilities (62.0-71.0%) of finding a fish, with the lowest probabilities (8.0-26.0%) associated with shallow ([less than or equal to] 2.5 m) sites (Table 4).
Low CPUEs of southeastern blue sucker relative to other large benthic Pearl River species were obvious throughout the study and were particularly striking given the fact that the electrofishing portion of this study was targeting habitats previously described as preferred by southeastern blue sucker. This species appears to comprise a small part of the thalweg-dwelling fish assemblage in the lower Pearl River and has adopted an uncharacteristically sedentary existence. Limited movements and small home ranges exhibited by southeastern blue suckers in this highly modified section of the Pearl River, although similar in magnitude to those reported by Peterson et al. (2000) in their Pearl River study, are orders of magnitude lower than those reported by Mettee et al. (2004) and Neely et al. (2009) for southeastern blue suckers in the Alabama River and blue suckers in the Missouri River. Given the acknowledged limitations of low numbers of tracked fish, limited recaptures, and missed tracking opportunities during very high water and extreme low water in our study, the small home ranges exhibited by fish in the Pearl River studies imply a high degree of habitat specificity (e.g., spending considerable time in limited areas) and selectivity (e.g., avoiding shallow locations with limited woody debris and gravel), suggesting southeastern blue suckers in this system are occupying small patches of acceptable habitat.
The major difference between the Pearl and Alabama River systems appears to be the higher degree of anthropogenic modification in the Pearl River. High site specificity and limited movements make these fish vulnerable to both local and regional disturbances, such as channelization, sedimentation, dam and sill construction, and riparian development. Rapid recolonization after local catastrophic events, such as the black liquor spill in 2012 (Vazquez, 2012), would potentially be difficult, given the small population size (Bart and Rios, 2003; Holcomb et al., 2015), and selection of possibly limited, deeper habitats with gravel and woody debris, and limited movements of these fish (this study). Further, the relatively high CPUEs and similar food habits of small mouth buffalo and channel catfish indicate that the low abundance of southeastern blue sucker in the main branch Pearl River is not due to contaminant-related mortality or food resources (Bailey and Harrison Jr., 1948; McComish, 1967; Perry Jr, 1969; Minckley et al., 1970; Peterson et al., 1999), suggesting habitat degradation and lack of recruitment are the likely causes of this population decline. Competition among the fishes cannot be ruled out, given these data, and warrants investigation, at least in the main channel of the Pearl River. The close proximity of recapture locations for tagged fish corroborates results from the radio telemetry study, again emphasizing the limited movements of these fish.
The geomorphology and hydrology of the west branch of the Pearl River has been modified to a much greater extent than the main branch. Although individual species CPUEs were not statistically significantly different between the two river branches, there was a consistent trend of lower CPUEs in the west branch. Modifications to this section of the river may be resulting in assemblage-wide reductions in fish abundances, regardless of taxa, raising concern that future modifications of the main branch of the river could further degrade associated habitat and reduce the abtindance of all benthic fishes, particularly southeastern blue sucker. River modifications that limit both spawning migrations and alter river hydrology, such as Ross Barnett dam and to a lesser extent the low head sill, are considered to be the most harmful to species like the southeastern blue sucker (Pflieger, 1997; Adams et al., 2006), potentially resulting in greater population impacts than those anticipated from global temperature increases (Graf, 1999). In combination the effects of future flow modifications and climate change (e.g., increased magnitude and flashiness of river flows; Arnell and Gosling, 2013) create an uncertain future at best for aquatic habitats and resident fishes in the main branch of the lower Pearl River.
Limited movements by tagged fish also suggest significant consequences for southeastern blue sucker reproduction in the lower Pearl River. Extended spawning movements that are typical of many sucker species in larger rivers (Tyus and Karp, 1990; McKinney et al, 1999; Cooperman and Markle, 2003), including Alabama River southeastern blue sucker (Mettee et al., 2004), and were not observed in the Pearl River population. Despite the small-scale movements reported for Pearl River fish by Peterson et al. (2000), the absence of directed upstream movements during the March-April spawning season was unexpected, particularly when all captured individuals exhibited well-developed breeding tubercles. In the sand-dominated Grand River in Missouri, Blue Suckers move upstream to locate riffle areas with cobble-sized substrate during spawning (Vokoun et al., 2003), and similar movements to preferred spawning habitats are suggested by Ross (2001) for blue suckers in Mississippi streams, based on the downstream transport of larvae. The small home ranges and absence of such movements by tagged Pearl River fish in the spring may reflect the lack of suitable spawning areas in the river, or in situ spawning within their home range areas. Our bathymetry and side-scan sonar data indicate, although coarse-substrate (gravel) riffle habitat does not exist in the Louisiana portion of the Pearl River, gravel substrates are present at many deeper outside bends. In the absence of migrations to spawning riffles, lower Pearl River southeastern blue suckers may be spawning in these gravel-substrate bend areas. Evidence against successful spawning and larval-juvenile survival in the lower Pearl River includes lack of sampling smaller fish less than age 4 (<400 mm), if growth rates are similar to the blue sucker (e.g., Eitzmann et al, 2007) in this study and in other recent Pearl River sampling efforts (e.g, Kelso el al, 2008; Vazquez, 2012; W.E. Kelso and M.D. Kaller, unpubl.; multi-gear sampling in 2016). In such a scenario, southeastern blue suckers in the lower river may be a sink population dependent on reproduction upriver in Mississippi, similar to bluehead and flannelmouth sucker populations above and below a salmonid barrier in the upper Colorado River system (Compton et al., 2008). Low spawning success and/or larval-juvenile survival may be contributing significantly to the imperiled status of the resident southeastern blue sucker population.
This study's telemetry and model for predicting the probability of finding a fish given the measured habitat parameters suggests that southeastern blue suckers in the lower Pearl River are associated with gravel areas with woody debris on the outside edge of deep bends (>3.7 m), similar to robust redhorse Moxostoma robustum (Grabowski and Jennings, 2009). Habitats associated with southeastern blue sucker have historically been difficult to sample with seines, resulting in a lack of knowledge about their population status in the Pearl River relative to other species (Gunning and Suttkus, 1991). An expansive sampling effort with multiple gears is warranted not only at historic collecting sites but throughout the Pearl River system to evaluate available habitat and current status of this catostomid, as well as the river redhorse Moxostoma carinatum, which has also declined precipitously in several systems throughout its range (Ross, 2001; Adams et al., 2006) and has not been encountered in the lower Pearl River in over a decade (H. L. Bart, pers. comm. (Tulane University)). Since the completion of this project and, in part, a result of these data, the conservation status of the southeastern blue sucker has been elevated in Louisiana (Holcomb et al., 2015) and multi-agency habitat and biotic assessments are underway. However, the primary management actions in the Pearl River remain navigation, flood control, and recreational and commercial access. This study identified habitat components that are important to resident southeastern blue suckers and vulnerabilities of these habitats, particularly to sedimentation. Spawning and rearing habitats, if present, remain unidentified, despite continued sampling (W.E. Kelso and M.D. Kaller, unpubl. ; multi-gear sampling in 2016). Unfortunately, given the current status of the lower Pearl River, the potential for significant population increases may already be limited in the largest river inhabited by this unique species.
Acknowledgments.--We would like to thank Hank Bart for his advice on the Pearl River and access to Tulane's historic records of southeastern blue suckers. Field work would not have been possible without the assistance from numerous undergraduates, graduate students, and research associates at Louisiana State University. This manuscript was approved for publication by the director of the Louisiana Agricultural Experiment Station as manuscript 2013-241-9643.
ADAMS, S., M. FLINN, B. BURR, M. WHILES, AND J. GARVEY. 2006. Ecology of larval blue sucker (Cycleptus elongatus) in the Mississippi River. Ecol. Freshw. Fish., 15:291-300.
ARNELL, W., N AND N., S. GOSLING. 2013. The impacts of climate change on river flow regimes at the global scale. J. Hydrol., 486:351-364.
BAILEY, R.M. AND H. M. HARRISON JR. 1948. Food habits of the southern channel catfish (Ictalurus lacustris punctatus) in the Des Moines River, Iowa. T. Am. Fish. Soc., 75:110-138.
BANISH, N.P., B.J. ADAMS, R.S. SHIVELY, M.M. MAZUR, D.A. BEAUCHAMP, AND T.M. WOOD. 2009. Distribution and habitat associations of radio-tagged adult Lost River suckers and shortnose suckers in Upper Klamath Lake, Oregon. T. Am. Fish. Soc., 138:153-168.
Bart, H.L. and N.E. Rios. 2003. Status of rare and protected inland fisheries of Louisiana. Final report, Tulane University.
BERTOLO, A., R. CARIGNAN, P. MAGNAN, B. PINEL-ALLOUL, D. PLANAS, AND E. GARCIA. 2005. Decoupling of pelagic and littoral food webs in oligotrophic Canadian Shield lakes. Oikos, 111:534-546.
BOLKER, B.M. 2008. Ecological models and data in R. Princeton, NJ: Princeton University Press, 337-339.
BURR, B. AND R. MAYDEN 1999. A new species of Cycleptus (Cypriniformes: Catostomidae) from Gulf Slope Drainages of Alabama, Mississippi, and Louisiana, with a review of the distribution, biology and conservation status of the genus. Bull. Ala. Mus. Nat. Hist., 20:19-57.
COKER, RE. 1930. Studies of common fishes of the Mississippi River at Keokuk: US Govt. Print. Off. Compton, R.I., W.A. Hubert, F.J. Rahel, M.C. Quist, and M.R. Bower. 2008. Influences of fragmentation on three species of native warmwater fishes in a Colorado River basin headwater stream system, Wyoming. N. Am. J. Fish. Manage., 28:1733-1743.
COOKE, S. 2003. Externally attached radio transmitters do not affect the parental care behaviour of rock bass. J. Fish. Biol, 62:965-970.
COOKE, S.J., C.M. BUNT, S.J. HAMILTON, C.A. JENNINGS, M.P. PEARSON, M.S. COOPERMAN, AND D.F. MARKLE. 2005. Threats, conservation strategies, and prognosis for suckers (Catostomidae) in North America: insights from regional case studies of a diverse family of non-game fishes. Biol. Conseru., 121:317-331.
COOPERMAN, M. AND D.F. MARKLE. 2003. Rapid out-migration of Lost River and shortnose sucker larvae from in-river spawning beds to in-lake rearing grounds. T. Am. Fish. Soc., 132:1138-1153.
DOUGLAS, N. AND R.JORDAN. 2002. Louisiana's inland fishes: a quarter century of change. Southeast. Fishes Counc. Proc., 1-10.
EITZMANN.J., A. MAKINSTER, .AND C. PAUKERT. 2007. Distribution and growth of blue sucker in a Great Plains river, USA. Fisheries Manag. EcoL, 14:255-262.
GEHEBER, A. D. AND K.R. PILLER. 2012. Spatio-temporal patters of fish assemblage structure in a coastal plain stream: appropriate scales reveal historic tales. Ecol. Freshwat. Fish., 14:255-262.
GRABOWSKI, T. AND J. ISELY. 2007. Spatial and temporal segregation of spawning habitat by catostomids in the Savannah River, Georgia and South Carolina, USA. J. Fish BioL, 70:782-798.
GRABOWSKI, T.B. AND C.A. JENNINGS. 2009. Post-release movements and habitat use of robust redhorse transplanted to the Ocmulgee River, Georgia. Aquat. Conserv., 19:170-177.
GRAE, W.L. 1999. Dam nation: A geographic census of American dams and their large-scale hydrologic impacts. Water Resour. Res., 35:1305-1311.
GUNNING, G. AND R. SUTTKUS. 1991. Species dominance in the fish populations of the Pearl River at two study areas in Mississippi and Louisiana: 1966-1988. Southeast. Fishes Counc. Proc, 7-15.
HANKIN, D.G. 1984. Multistage sampling designs in fisheries research: applications in small streams. Can. J. Fish. Aquat. Sci., 41:1575-1591.
--AND G.H. REEVES. 1988. Estimating total fish abundance and total habitat area in small streams based on visual estimation methods. Can. J. Fish. Aquat. Sci., 45:834-844.
HODDER, K.H., J.E.G, MASTERS, W.R.C.. BEAUMONT, R.E. GOZLAN, A.C. PINDER, C.M. KNIGHT, AND R.E. KENWARD. 2007. Techniques for evaluating the spatial behaviour of river fish. Hydrobiologia, 582:257-269.
HOLGOMB, S.R., A.A. BASS, C.S. REID, M.A. SEYMOUR, N.F. LORENZ, B.B. GREGORY, S.M. JAVED, AND KF. BALKUM. 2015. Louisiana Wildlife Action Plan. Louisiana Department of Wildlife and Fisheries. Baton Rouge, LA.
Jolly, G.M. 1965. Explicit estimates from capture-recapture data with both death and immigration-stochastic model. Biometrika, 52:225-247.
KAESER, A.J. AND T.L. LITTS. 2008. An assessment of deadhead logs and large woody debris using side scan sonar and field surveys in streams of southwest Georgia. Fisheries, 33:589-597.
--AND--. 2010. A novel technique for mapping habitat in navigable streams using low-cost side scan sonar. Fisheries, 35:163-174.
--, LRRRS T.L., AND T. TRACY. 2013. Using low-cost side-scan sonar for benthic mapping throughout the lower flint river, Georgia, USA. River Res. Appl., 29:634-644.
KELSO, W., A. HARLAN, AND M. KALLER. 2008. A survey of fishes inhabiting the Pearl, Tchefuncte, and Tangipahoa river systems in Louisiana. Baton Rouge: Louisiana Department of Wildlife and Fisheries, Project Report.
KERY, M., AND J.M. ROYLE. 2016. Applied Hierarchical Modeling in Ecology. Academic Press. Elsevier, Inc., London, United Kingdom.
LEE, D.S., C.R. GILBERT, C.H. HOCUTT, R.E. JENKINS, D.E. MCALLISTER, AND J.R. STAUFEER JR. 1980. Atlas of North American freshwater fishes: North Carolina State Museum of Natural History Raleigh.
MCCOMISH, T.S. 1967. Food habits of bigmouth and smallmouth buffalo in Lewis and Clark Lake and the Missouri River. T. Am. Fish. Soc., 96:70-74.
MCDONALD, D.B., T.L. PARCHMAN, M.R. BOWER, W.A. HUBERT, AND F.J. RAHEL. 2008. An introduced and a native vertebrate hybridize to form a genetic bridge to a second native species. P. Natl. A. Sci., 105:10,837-10,842.
MCKINNEY, T., W.R. PERSONS, AND R.S. ROGERS. 1999. Ecology of flannelmouth sucker in the Lee's Ferry tailwater, Colorado River, Arizona. West. N. Am. Naturalist, 59:259-265.
MCMAHON, T., A. ZAI.E, D. ORTH. 1996. Aquatic habitat measurements, p. 83-120. In: B. Murphy and Willis D. (eds). Fisheries techniques. American Fisheries Society, Bethesda, MD.
METTEE, M., T. SHEPARD, AND P. O'NEIL, W. HENDERSON JR AND S. MCGREGOR. 2004. Status survey of the southeastern blue sucker Cycleptus meridionalis in the Alabama River, 1995-2004. Final Report, Geological Survey of Alabama.
MINCKLEY, W., J.E. JOHNSON, J.N. RINNF., AND S.E. WILLOUGHBY. 1970. Foods of buffalo-fishes, genus Ictiobus, in central Arizona reservoirs. T. Am. Fish. Soc.. 99:333-342.
NEELY, B.C., M.A. PECC, AND G.E. MESTL. 2009. Seasonal use distribution and migrations of blue sucker in the Middle Missouri River. Ecol. Freshw. Fish., 18:437-444.
--, --, AND --. 2010. Seasonal resource selection by blue suckers Cycleptus elongatus. J. Fish Biol, 76:836-851.
NELSON, J.S., E.J. CROSSMAN, H. ESPINOSA-PEREZ, L.T. FINDLEY, C.R GILBERT, R.N. LEA, AND J.D. WILLIAMS.2004. Common and scientific names of fishes from the United States, Canada and Mexico: American Fisheries Society.
OKLAND, F., C. HAY, T. NAESJE, N. NICKANDOR, AND E. THORSTAD. 2003. Learning from unsuccessful radio tagging of common carp in a Namibian reservoir. J. Fish Biol., 62:735-739.
PERRY JR, W.G. 1969. Food habits of blue and channel catfish collected from a brackish-water habitat. Prog. Fish Cult., 31:47-50.
PETERSON, M.S., L.C. NICHOLSON, G.L. FULLING, AND D.J. SNYDER. 2000. Catch-per-unit-effort, environmental conditions and spawning migration of Cycleptus meridionalis Burr and Mayden in two coastal rivers of the northern Gulf of Mexico. Am. Midi. Nat., 143:414-421.
--, --, D.J. SNYDER, AND G.L. FULLING. 1999. Growth, spawning preparedness, and diet of Cycleptus meridionalis (Catostomidae). T. Am. Fish. Soc., 128:900-908.
PETERSON, R.C., C.A. JENNINGS, AND J.T. PETERSON. 2013. Relationships between river discharge and abundance of age 0 redhorses (Moxostoma spp.) in the oconee river, Georgia, USA, with implications for robust redhorse. River Res. Appl., 29:734-742.
PFLIEGER, W.L. 1997. The fishes of Missouri. Missouri Department of Conservation, Jefferson, MO.
RASMUSSEN, J.E. 2011. Status of Lost River sucker and shortnose sucker. West. N. Am. Naturalist, 71:442-455.
REID, S. 2009. Age, growth and mortality of black redhorse (Moxostoma duquesnei) and shorthead redhorse (M. macrolepidotum) in the Grand River, Ontario. J. Appl. Ichthyol, 25:178-183.
REID, S.M., N.E. MANDRAK, L.M. CARL, .AND C.C. WILSON. 2008. Influence of dams and habitat condition on the distribution of redhorse (Moxostoma) species in the Grand River watershed, Ontario. Environ. Biol. Fish., 81:111-125.
ROGERS, K.B. AND G.C. WHITE. 2007. Analysis of Movement and Habitat Use from Telemetry Data. p. 625-668. In: C.S. Guy and M.L. Brown (eds). Analysis and Interpretation of Freshwater Fisheries Data. Bethesda, MD: American Fisheries Society
ROSS, S.T. 2001. The inland fishes of Mississippi. University Press of Mississippi, Jackson, Mississippi.
SANTUCCI JR, V.J., S.R. GEPHARD, AND S.M. PESCITELLI. 2005. Effects of multiple low-head dams on fish, macroinvertebrates, habitat, and water quality in the Fox River, Illinois. N. Am. f. Fish. Manage., 25:975-992.
SCHULTZ, L.D. AND K.N. BERTRAND. 2012. Long term trends and outlook for mountain sucker in the Black Hills of South Dakota. Am. Midi. Nat., 167:96-110.
SCOTT, W.B. AND E.J. CROSSMAN. 1998. Freshwater Fishes of Canada, Gait House Publications Ltd, Oakville, Ontario.
SEBER, G.A.F. 1965. A note on the multiple-recapture census. Biometrika, 52:249-259.
SMITH, C.T., S.B. REID, L. GODFREY, AND W.R. ARDREN. 2011. Gene flow among Modoc sucker and Sacramento sucker populations in the upper Pit River, California and Oregon. J. Fish Wildl. Manage., 2:72-84.
TYUS, H.M. 1988. Long-term retention of implanted transmitters in Colorado squawfish and razorback sucker. N. Am. J. Fish. Manage., 8:264-267.
--AND C.A. KARP. 1990. Spawning and movements of razorback sucker, Xyrauchen texanus, in the Green River basin of Colorado and Utah. Southwest. Nat., 427-433.
VAZQUEZ, J.A. 2012. Fish and Macroinvertebrate Assemblage Composition and Diversity at Revetted Banks in the Pearl River and the Response of These Assemblages to a Paper Mill Effluent Spill. M.S. Thesis, Baton Rouge: Louisiana State University, 60 p.
VOKOUN, J.C., T.L. GUERRANT, AND C.F. RABENI. 2003. Demographics and chronology of a spawning aggregation of blue sucker (Cycleptus elongatus) in the Grand River, Missouri, USA. J. Freshwater Ecol., 18:567-575.
WFIGEL, B.M., J. LYONS, AND P.W. RASMUSSEN. 2006. Fish assemblages and biotic integrity of a highly modified floodplain river, the upper Mississippi, and a large, relatively unimpacted tributary, the lower Wisconsin. River Res. Appl., 22:923-936.
WONG, W. AND J. LEE. 2005. Statistical analysis of geographic information with ArcView GIS and ArcGIS. Wiley, Hoboken, NJ, 203-208.
YODER, C.O. AND R.A. BEAUMIER. 1986. The occurrence and distribution of river redhorse, Moxostoma carinatum and greater redhorse, Moxostoma valenciennesi in the Sandusky River, Ohio. Ohio J. Sci., 86:18-21.
ZUUR, A.F., E.N. IENO, N.J. WALKER, A.A. SAVEUEV, AND G.M. SMITH. 2009. Mixed Effects Models and Extensions in Ecology in R. Springer Science + Business Media, LLC, New York, New York.
SUBMITTED 9 MARCH 2016
ACCEPTED 9 DECEMBER 2016
DEVON C. OLIVER (1), WILLIAM E. KELSO and MICHAEL D. KALLER (2)
School of Renewable Natural Resources, Louisiana State University Agricultural Center, 227 RNR Building, Baton Rouge 70803
(1) Corresponding author present address: Department of Zoology, Southern Illinois University, Carbondale, Illinois, 62901; Telephone: (618); 453-2608; FAX: (618) 453-6944; e-mail: dolive3@siu. edu
(2) Department of Experimental Statistics, LSU Agricultural Center, 161 Martin D. Woodin Hall, Baton Rouge, Louisiana 70803
Caption: Fig. 1.--Map of the lower Pearl River study area, Louisiana, U.S.A. Former Navigation channel -89.862, 30.584 (Decimal Degrees); Main Branch Pearl River-89.822, 30.790; West Branch Pearl River -89.721, 30.372
TABLE 1.--Mean Catch per unit effort (CPUE; fish per min) of benthic fishes collected in 2010 and 2011 from the main branch and west branch of the lower Pearl River. Letters associated with CPUE values reflect significant differences among species within river branches assessed at [alpha] = 0.05 Fish Main Tukey West Tukey branch grouping branch grouping CPUE CPUE Southeastern blue sucker 0.05 B 0 B Blacktail redhorse 0 B 0.16 B Highfin carpsucker 0.07 B 0.03 B Quillback 0.11 B 0 B Smallmouth buffalo 4.33 A 0.49 A Channel catfish 4.36 A 0.30 B Flathead catfish 4.97 A 0.17 B TABLE 2.--Tag frequency, fish length, tagging date, and calculated home ranges for 11 southeastern blue suckers in the lower Pearl River Fish Length Tag Tag Number of Home (mm) frequency date successful ranges locations 1 602 164.402 8/8/2011 36 3.8 km 2 665 164.502 8/16/2011 33 0.7 km 3 630 165.607 8/16/2011 32 0.52 km, 1.26 km 4 622 164.702 8/29/2011 3 0.49 km 5 589 165.507 10/5/2011 34 0.55 km 6 535 164.201 10/5/2011 33 0.94 km, 0.16 km, 1.6 km 7 627 165.006 3/7/2012 7 0.03 km 8 603 164.302 3/7/2012 7 0.3 km 9 520 165.399 3/7/2012 7 0.47 km 10 520 165.707 3/7/2012 5 0.21 km 11 469 165.302 3/7/2012 7 0.57 km TABLE 3.--The top five models ranked in descending order; (+ (NS)) variable included and not significant, (+) variable included and significant, (-) variable not included Depth Gravel Wood Temp. Velocity Cond. Outside Turbid. + + + + - - - - + + + - + (ns) - - - + + + - - - - + (NS) + + + - - + (NS) - - + + + - - - + - Depth AIC [X.sup.2]/df + -41.53 1.1 + -30.14 1.12 + -30.79 1.12 + -32.41 1.12 + -43.71 1.13 Temp. (Temperature), Cond. (Specific Conductance), Turbid. (Turbidity) TABLE 4.--Characteristics of the 10 highest and 10 lowest predicted probabilities of finding a fish at a given location predicted from corresponding parameter values Characteristics of locations with > 60% probability of southeastern blue suckers Outside Bend or North or South Temperature (C) Inside Bend Outside (100%) North (100%) 11.24-32.96 Characteristics of locations with < 27% probability of southeastern blue suckers Outside Bend or North or South Temperature (C) Inside Bend Inside (70%) North (50%) 13.08-31.01 Outside (30%) South (50%) Characteristics of locations with > 60% probability of southeastern blue suckers Outside Bend or Wood Presence Gravel Presence Depth (m) Inside Bend Outside (100%) Yes (100%) Yes (100%) 3.71-5.51 Characteristics of locations with < 27% probability of southeastern blue suckers Outside Bend or Wood Presence Gravel Presence Depth (m) Inside Bend Inside (70%) Yes (20%) Yes (60%) 1.07-2.5 Outside (30%) No (80%) No (40%)
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|Author:||Oliver, Devon C.; Kelso, William E.; Kaller, Michael D.|
|Publication:||The American Midland Naturalist|
|Date:||Apr 1, 2017|
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