Redbreast Sunfish Lepomis Auritus Research Articles

I spy: Factors influencing the observation of oxytetracycline in calcified structures of fishes viewed using standard light and fluorescence microscopy.

The antibiotic oxytetracycline (OTC) is a fluorochrome marker, and fluorescence microscopy is used to view OTC marks in fishes' calcified structures. However, OTC marks have been observed in calcified structures using standard light microscopy for multiple species. Therefore, we conducted an experiment to investigate potential factors (i.e., season, total length of fish, growth rate, and sex) influencing the observation of OTC in calcified structures (otoliths and fin rays or spines) from channel catfish Ictalurus punctatus, gray redhorse Moxostoma congestum, Guadalupe bass Mircopterus treculii, and redbreast sunfish Lepomis auritus viewed using standard light and fluorescence microscopy. OTC stains were not observed in any otoliths under standard light; however, OTC marks were commonly observed in I. punctatus spines using standard light microscopy (56.2%). Ninety-nine percent of otoliths and 88.9% of spines and fin rays had a visible fluorescent OTC mark when viewed using fluorescence microscopy. There was a negative relationship between the observed OTC mark and total length of fish for each season, but fish injected in the summer had the most structures with an observed OTC mark under either light condition. Understanding how OTC marking is affected by biological processes and environmental conditions will assist in future studies that rely on chemical marking of calcified structures by increasing efficacy of OTC marking and interpretation of marks.

Identification of non-native populations and reconstruction of invasion routes in the Redbreast Sunfish Lepomis auritus

Identification of non-native populations and reconstruction of invasion routes in the Redbreast Sunfish Lepomis auritus

Proposed Standard Weight (Ws) Equations and Standard Length Categories for Redbreast Sunfish and Spotted Sunfish

AbstractWe developed standard weight (Ws ) equations for Redbreast Sunfish Lepomis auritus and Spotted Sunfish L. punctatus using the traditional regression‐line‐percentile (RLP) technique and the empirical‐percentile‐linear (EmP‐L), and the empirical‐percentile quadratic (EmP‐Q) method. Individual length and weight data for 175,541 Redbreast Sunfish from 8 to 31 cm TL across 315 populations and 66,851 Spotted Sunfish from 7 to 21 cm TL across 130 populations were used in the final analysis. These fish were collected from 1975 to 2021 by various agency and university personnel from most known populations across the species' native and introduced ranges in North America. We present the EmP‐L‐derived Ws equations for the Redbreast Sunfish as log10W = 3.1218 × log10L − 5.0018 and the Spotted Sunfish as log10W = 3.3343 × log10L − 5.3739, where W is weight (g) and L is total length (TL, mm). Equations from all methods exhibited length‐related bias, but the EmP‐L equations had a median bias of 0–0.6 for the length range that comprised 99.7% (for 8–24 cm TL) of Redbreast Sunfish and 99.0% (for 7–18 cm TL) of Spotted Sunfish in our data set. Regardless of the equation, the most bias was found at the upper end of the length spectrum, so we do not recommend these equations for Redbreast Sunfish ≥30 cm TL or Spotted Sunfish ≥20 cm TL. We also developed standard length categories for Redbreast Sunfish with minimum lengths for five standard length categories of 8, 13, 18, 20, and 25 cm TL for stock, quality, preferred, memorable, and trophy sizes and for Spotted sunfish 5, 10, 13, 15, and 18 cm TL, respectively. Development of a Ws equation and standard length categories will aid biologists in assessing condition and size structure of wild Redbreast Sunfish and Spotted Sunfish populations and those being propagated for supplemental stocking into areas with depressed native populations.

The role of flow dependency and water availability in fish assemblage homogenization in tributaries of the Chattahoochee River, Alabama, USA

AbstractThe availability of water is becoming more variable as flow regime alterations intensify both locally and on a global scale. This pattern has been observed in the tributaries of the central Chattahoochee River System as water withdrawal and natural drought have caused flows to diminish. Stream discharge has steadily decreased in the study area by 31% over the last 50 years, and during this time, fish assemblage homogenization has occurred throughout the system. Our primary objective was to assess whether spawning mode and water availability are catalysts for fish assemblage change in tributaries of the Chattahoochee River System. We found that species which prefer or have adapted to low flow conditions (e.g. blacktail shiner Cyprinella venusta, redbreast sunfish Lepomis auritus and blackbanded darter Percina nigrofasciata) are becoming dominant and replacing historically dominant fluvial specialists. When examining short‐term changes between a dry year (2009) and a wet year (2010), some species preferring higher flows such as the highscale shiner Notropis hypsilepis were detected during the wet year, suggesting that the amount of water is important for the presence of these species in upstream reaches where they were historically abundant. Species that can reproduce successfully in low flow conditions are thriving and expanding their native ranges as more habitat becomes suitable. Species that require higher flows for part of their life cycle, however, appear to be declining from upstream areas as water availability continues to decrease, despite temporary recovery from downstream refugia during wet years.

Optimizing a Standardized Electrofishing Sampling Protocol for Warmwater Resident Sportfish in the Tallapoosa River, Alabama, USA

AbstractA two‐year electrofishing study was initiated in the Tallapoosa River, Alabama, to identify an optimal standardized sampling program for three principal resident sportfish: Alabama bass Micropterus henshalli, redbreast sunfish Lepomis auritus, and redeye bass Micropterus coosae. Samples were conducted in spring (May), summer (July), and fall (October) in 2010 and 2011 from seven 1‐h transects. Spring samples of Alabama bass had lower catch per effort (CPE) and were more skewed towards fish between 200 and 300 mm total length (TL) than samples in other seasons; whereas, fall samples collected more redeye bass >200 mm TL but CPE was similar among seasons. Fewer, but larger, redbreast sunfish were sampled during fall compared with other seasons. Mean CPE of all three species was independent of transect duration. The total time spent electrofishing and processing fish in order to estimate a mean CPE with a specified precision was a function of transect duration and CPE. More effort was needed as CPE decreased for most species, but the relations between transect duration and total effort were parabolic. A precision of within 10% of the mean CPE was unattainable for most species as a result of logistic considerations. Based on the results of this study, it appears that fall is the optimal sampling time for these species in the Tallapoosa River and the optimal transect duration is likely 10 min. At a precision level of 20% of the mean, the number of 10‐min transects required ranged from 5 to 40, with a total sample time for each individual species of 0.82–7.16 h. Copyright © 2014 John Wiley & Sons, Ltd.

Summer Thermal Thresholds of Fish Community Transitions in Connecticut Streams

AbstractThermal tolerances have been studied for individual fish species but few have investigated how stream fish assemblages respond along a temperature gradient and which thermal ranges act as a threshold, triggering discernible community change. The purpose of this study was to define summer temperature thresholds of fish community transitions in Connecticut streams. The program Threshold Indicator Taxa Analysis suggested that the coldwater class had a June–August mean water temperature < 18.29°C, the coolwater class 18.29–21.70°C, and a warmwater class > 21.70°C. Significant indicator species of coldwater streams were Slimy Sculpin Cottus cognatus and Brook Trout Salvelinus fontinalis. Significant indicator species of warmwater streams were Cutlip Minnow Exoglossum maxillingua, Smallmouth Bass Micropterus dolomieu, Rock Bass Ambloplites rupestris, Brown Bullhead Ameiurus nebulosus, Redbreast Sunfish Lepomis auritus and Yellow Bullhead A. natalis. The narrow 3.41°C temperature range between the coldwater and warmwater thresholds was designated as a coolwater transition zone, with potential for the presence of both coldwater and warmwater species and lack of species uniquely associated with this thermal range. Our approach based on a robust set of water temperature and fish community data should be applicable to other temperate regions and will be useful for informing development of thermal criteria, application of multimetric indices, and planning for anticipated effects of climate change.Received July 2, 2013; accepted October 8, 2013Published online January 30, 2014

Effects of Small Dams on Sunfish Assemblages in North Carolina Piedmont and Coastal Plain Streams

AbstractOver the past century dams have played a major role in restructuring North American stream communities. Effects of large dams on fish assemblages are well studied; however, effects of small dams are relatively unstudied. Sunfishes (family Centrarchidae) include many meso‐ and apex predators that are key components of North American lotic and lentic ecosystems. Additionally, centrarchids are widely introduced into impoundments well beyond their native ranges. Here, we examine sunfish assemblages at 75 sites associated with small dams in the Neuse, Tar, and Roanoke drainages in North Carolina. We predicted that streams with intact dams would have more introduced centrarchids than streams with breached or relict dams in response to dam‐induced shifts in assemblage structure. Contrary to our predictions, streams with breached dams had significantly higher numbers of introduced centrarchids, but total and native centrarchid richness were not significantly different from streams with intact dams. Streams with relict dams had significantly lower total and native centrarchid richness; exotic centrarchids did not differ between streams with intact and relict dams. Abundance of the most frequently encountered native taxon (Redbreast Sunfish Lepomis auritus) did not differ across dam types, and the abundance of the most frequently encountered exotic taxon (Bluegill L. macrochirus) was only significantly different (lower) in streams with relict dams. These data suggest that low‐head–small dams have unanticipated and potentially long‐lasting effects on stream fish communities. Moreover, they suggest a need to (1) reevaluate current views of breached dams as benign structures, and (2) develop a more holistic approach to prioritizing dams for removal.

A Digital Underwater Video Camera System for Aquatic Research in Regulated Rivers

AbstractWe designed a digital underwater video camera system to monitor nesting centrarchid behavior in the Tallapoosa River, Alabama, 20 km below a peaking hydropower dam with a highly variable flow regime. Major components of the system included a digital video recorder, multiple underwater cameras, and specially fabricated substrate stakes. The innovative design of the substrate stakes allowed us to effectively observe nesting redbreast sunfish Lepomis auritus in a highly regulated river. Substrate stakes, which were constructed for the specific substratum complex (i.e., sand, gravel, and cobble) identified at our study site, were able to withstand a discharge level of approximately 300 m3/s and allowed us to simultaneously record 10 active nests before and during water releases from the dam. We believe our technique will be valuable for other researchers that work in regulated rivers to quantify behavior of aquatic fauna in response to a discharge disturbance.

Three New Species of Philometrids (Nematoda: Philometridae) from Centrarchid Fishes in the USA

The following 3 new species of the Philometridae (Nematoda: Dracunculoidea) are described from freshwater centrarchid fishes (Centrarchidae: Perciformes) from eastern North America on the basis of museum and newly collected specimens: Philometra orbitalensis n. sp. and Philometroides aphanonaris n. sp. from the oculo-orbits and subcutaneous tissues of the head, respectively, of the largemouth bass Micropterus salmoides, and Philometroides wellborni n. sp. from the oculo-orbits of the bluegill Lepomis macrochirus (type host) and the redbreast sunfish Lepomis auritus. Whereas P. wellborni is described from both males and gravid females, the males of P. aphanonaris and P. orbitalensis remain unknown. The type locality of all 3 species is the West Point Reservoir, Alabama-Georgia; P. aphanonaris and P. wellborni have also been recorded from the Santee River in South Carolina. In contrast to other Philometra spp. parasitizing North American freshwater fishes, the gravid females of P. orbitalensis are characterized by large cephalic papillae of the external circle, yellowish body color, location (oculo-orbits) in the host, and by the host type (Centrarchidae). Philometroides aphanonaris and P. wellborni differ from North American congeners from freshwater fishes in the absence of esophageal teeth or a different embossment of the caudal end in gravid females; P. wellborni differs from P. aphanonaris in the absence of cuticular bosses from the caudal end of gravid females and in some other features (extent of embossment, body color, location, and host type).

Reproductive Ecology of Redbreast SunfishLepomis auritusin a Virginia Stream

Abstract In North Anna River, Virginia, redbreast sunfish Lepomis auritus began spawning in late May, 1992, when water temperatures exceeded 20°C. Spawning occurred in pool habitat with low velocities (<0.10 m/s) and water deeper than 0.5 m, consistent with previous reports. Nest densities declined into the summer and variation in nest density was explained by a single predictor (log degree-days). All nests constructed in May were destroyed by high flow, whereas 30 of 51 nests built later were successful in producing swim-up fry. Overall nest success was 33%. Multivariate separation (MANOVA) with 21 habitat-related variables was not significant, suggesting that reproductive success during periods of stable flow was not related to variables measured and may be influenced by biotic factors, such as predation.