Cambarus Bartonii Research Articles

Do crayfish affect stream ecosystem response to riparian vegetation removal?

Abstract Riparian vegetation management alters stream basal resources, but stream ecosystem responses partly depend on top‐down interactions with in‐stream consumers. Large‐bodied omnivores can exert particularly strong influences on stream benthic environments through consumption of food resources and physical disturbance of the benthos. Trophic dynamics studies conducted within the context of reach‐scale riparian vegetation manipulations can provide insights into the interactions and relative importance of top‐down and bottom‐up controls that determine ecosystem response to riparian change. Here, we examine how top‐down control by native crayfish omnivores (Cambarus bartonii) interacts with abiotic conditions created by reach‐scale removal of riparian rhododendron (Rhododendron maximum) in the southern Appalachian Mountains of the U.S.A. We conducted 32‐day trophic experiments by nesting five pairs of electrified (crayfish excluded) and non‐electrified (crayfish access) plots within each of two 300‐m stream reaches (one control and one rhododendron‐removed) for 1 year pre‐removal and 2 years post‐removal. Algal growth responded positively to the reduced canopy cover (post‐rhododendron removal) only under low flow conditions combined with the absence of top‐down control by crayfish. Leaf decomposition rates were reduced by c. 40% in the absence of crayfish, but higher inputs of rhododendron leaf litter during the summer following rhododendron removal reduced the effect of crayfish presence on decomposition. Riparian rhododendron removal also significantly increased benthic sediment and fine benthic organic matter, but crayfish exclusion did not affect these stream properties. Potential long‐term reductions in crayfish abundance could reduce the top‐down effects of crayfish and ultimately lead to higher algal growth and reduced leaf decomposition rates in streams where rhododendron is managed through removal.

English

Abstract Crayfish are an aquatic fauna of conservation concern, yet regional studies are lacking on zoogeography and life history. We compared recent and historical species distribution data and assessed conservation standings of native and nonindigenous crayfish of the Potomac River Basin in West Virginia. From 2007–2011, a total of 1764 crayfish were collected from 159 sites. Data collection included species abundance, morphometrics, and life history parameters. Percentages of the number of individuals of each species of the total catch were 36.3% (Cambarus bartonii), 34.6% (Faxonius obscurus), 23.4% (Faxonius virilis), 3.6% (Procambarus cf. zonangulus) and 2.0% (Cambarus carinirostris). Cambarus bartonii was present throughout the drainage, F. obscurus was collected primarily from the North Branch, South Branch, and Cacapon river watersheds, and C. carinirostris was only collected in the South Branch watershed. Two nonnative species, F. virilis and P. cf. zonangulus, were only present in tributaries downstream of the Cacapon River watershed. Spinycheek crayfish (Faxonius limosus) were not collected during our survey, which suggests its possible extirpation from the West Virginia portion of its range. Our zoogeographic and life history data could serve as a baseline for future conservation-oriented monitoring efforts of the Potomac River watershed.

Dry and Ash Free Dry Mass to Length Relationships and Salinity Stress Response of Rock Crayfish (Cambarus carinirostris) and Allegheny Crayfish (Faxonius obscurus)

During the cold months in the northeastern United States, road salt is used to de-ice roads. The increase in human population and road density has led to a dramatic increase in salt application over the past 30 years. As a result, salinity levels of freshwater streams are rising at a rapid rate which has led to habitat degradation in aquatic ecosystems and a harmful effect on the health of many freshwater organisms. Crayfish responses to salinity may be indicative of how other freshwater macroinvertebrates react to increased salinity levels. This project explores the impact of increased salinity levels on the stress levels of two West Virginia natives, the Rock Crayfish (Cambarus carinirostris) and the Allegheny Crayfish (Faxonius obscurus). We measured the change in respiration through the tracking of dissolved oxygen levels through the use of a respiration chamber and varying salt solutions from common road salt deicer. All specimens were dried and ashed to record dry mass (DM) and ash-free dry mass (AFDM). We then created species level regressions to predict DM and AFDM from carapace length (CL). In 2010, Benke et al. published an order level regression for Decapoda to predict DM from CL, and a species level regression for Cambarus bartonii to convert between CL and AFDM. We found significant difference Benke’s regressions and our regressions, indicating the possible need for species specific regression equations to estimate crayfish biomass.

Local Ecosystem Uptake of Stocked Trout by Cambarus bartonii and the Relevance of Prior Exposure to Stocking

We assessed variation in feeding preference of Cambarus bartonii (Appalachian Brook Crayfish) for stocked Salmo trutta (Brown Trout) or wild Salvelinus fontinalis (Brook Trout) across 8 central Pennsylvania headwater streams with different recent exposures to trout stocking. In separate trials, we allowed crayfish to interact with and choose between fillets of stocked Brown Trout or wild Brook Trout in either a flowing Y-apparatus or a standing-water aquarium. In the Y-apparatus trials and standing water aquarium trials, crayfish exhibited no detectable feeding preference based on proximity to stocking sites from which they were collected. In the Y-apparatus trials, crayfish were more likely to move towards a fillet type than not. Overall, our results provide evidence that crayfish do not distinguish between stocked Brown Trout and wild Brook Trout as food sources, and history of exposure to stocked trout does not influence feeding preference. Specifically, crayfish accept stocked trout as a food source, even if this resource is new to the environment (i.e., with the additions of new stocking sites in previously unstocked streams). Acceptance of stocked trout as a food resource suggests crayfish may play an important role in the local incorporation of this significant allochthonous nutrient input. Future research should address if local uptake of stocked trout by crayfish is able to mitigate downstream nutrient loads related to stocking.

Preliminary survey of Aphanomyces sp. associated with native and invasive crayfish in the Lower Susquehanna watershed of South Central Pennsylvania

The oomycete species, Aphanomyces astaci, is well known as the devastating causal agent of European crayfish plague. Despite assumptions of a North American origin, the prevalence and distribution of A. astaci in its presumed native range is unknown. In this study, we modified published PCR-based diagnostic methods to detect Aphanomyces sp. in both whole crayfish and in environmental DNA from bulk water samples. Putatively positive samples were sequence-verified as A. astaci, and pure cultures were obtained from four individual crayfish. Our results suggest that a single genotype of A. astaci is present in at least six out of ten locations sampled within the Lower Susquehanna watershed, and is associated with three non-native species, including Faxonius rusticus, the rusty crayfish. Aphanomyces were not detected directly from native crayfish, Cambarus bartonii, but both A. astaci and an unknown Aphanomyces species were detected from corresponding environmental DNA samples. Although North American crayfish are considered less susceptible to A. astaci infection, future studies should interrogate the impact of invasive species, such as the rusty crayfish, and land use changes on potential host-pathogen dynamics.

Observation of a Cambarus bartonii bartonii (Common Crayfish) Overwintering in a Terrestrial Winter Microhabitat

In cool climates, crayfish that are not primary burrowing species are typically thought to retreat into deeper waters in winter and may seek refuge in small aquatic burrows or interstitial spaces associated with aquatic substrates. Herein, I report a novel observation of a juvenile Cambarus bartonii bartonii (Common Crayfish) during winter within eastern Pennsylvania occupying a terrestrial microhabitat consisting of moist, terrestrial leaf litter associated with a small depression in an upland forest. I found the crayfish in association with a small aggregation of Plethodon cinereus (Eastern Red-backed Salamander). Requirements of a hibernaculum by the salamanders with sufficient moisture and buffered from freezing may have also provided sufficient conditions for the crayfish to utilize the depression as a winter refugium.

Crayfishes of the Potomac River Basin in West Virginia

The high level of endemism displayed by native crayfish taxa, in addition to the recognized displacement abilities of nonindigenous crayfish such as Faxonius virilis and Procambarus acutus represents a serious threat to indigenous crayfish populations. Other major conservation threats to native crayfish fauna in the eastern portion of West Virginia include land development and land-use practices. The goal of this study was to compare recent and historical species distributions and assess conservation standings of native and nonindigenous crayfishes of the Potomac River Basin in West Virginia. Between June and October of 2007 historical and semi-randomly selected sites were sampled throughout the basin. Abundance was determined by catch per unit effort (CPUE) for ten seine hauls. Morphometric data including total carapace length, propodus length, and palm length were recorded in millimeters for each species. Life history parameters were determined from collections made during the study. Native species collected included Cambarus bartonii, Cambarus carinirostris, and Faxonius obscurus. Introduced species collected included Faxonius virilis and Procambarus zonangulus. C. bartoni was present in the Cacapon, North Branch Potomac, Potomac Direct Drains, and South Branch Potomac. F. obscurus was absent from Potomac Direct Drains, and C. carinirostris was only present in the South Branch Potomac. F. virilis and P. zonangulus were only present in Potomac Direct Drains. Though F. limosus was reported in 1989, no specimens were recovered during over the course of this survey, which indicates possible extirpation from the West Virginia portion of its range.

English

Abstract In crayfish, intraspecific coloration can vary due to a variety of factors such as diet, genetic variation, environment, and ontogeny. Ortmann (1906) hypothesized that the crayfish Cambarus bartonii bartonii and Faxonius obscurus exhibit an ontogenetic shift in color change, with greener coloration in younger individuals of both species diminishing with age in larger specimens. However, this hypothesis has never been quantitatively tested. This work incorporated digital image analysis to quantify coloration of samples of C. b. bartonii and F. obscurus collected from two locations, respectively, in an eastern Pennsylvania stream. Examination for relationships between coloration (percent “green dominance”, i.e., the proportion of green in comparison to blue and red in photographs) and body size did not reveal any significant relationship between these variables in either crayfish species. Therefore, this study does not support the presence of ontogenetic color change in C. b. bartonii and F. obscurus, and suggests intraspecific variation of color in both species may be primarily influenced by other factors.

A crayfish survey of the fishing creek watershed in northeastern Pennsylvania suggests widespread prevalence of a nonindigenous species and the absence of a native congener

Abstract Introduction of nonindigenous crayfish species impacts freshwater ecosystems and can result in displacement of native crayfish. The crayfish Orconectes limosus and Cambarus bartonii are native to the Susquehanna River drainage in Pennsylvania. However, several nonindigenous crayfish have become established in this drainage. No comprehensive survey exists on crayfish species within the Fishing Creek watershed. Historic records report O. limosus and C. bartonii in this watershed; however, recent point surveys have documented the presence of the nonindigenous crayfish O. obscurus. We sampled crayfish in 15 sites from the lower reaches of Fishing Creek through its headwaters and major tributaries. We collected a total of 484 crayfish, representing the species O. obscurus and C. bartonii. We found O. obscurus within much of Fishing Creek and some tributaries, but absent from the upper reaches of the watershed, possibly due to a series of dams. C. bartonii were primarily found in the upper portions of the Fishing Creek watershed, but also found at low abundance with O. obscurus in the central portions of the watershed and in a small, first order tributary. We collected no O. limosus specimens in our samples, suggesting local extirpation via displacement by O. obscurus, as has been reported elsewhere.

New Records of Entocytherid Ostracods from New York and New Jersey

Abstract Ostracods of the family Entocytheridae are obligate ectosymbionts, primarily of crayfishes. Although the distribution and diversity of crayfishes is well known in the northeastern US, little is known about entocytherids in this region. In this study, we examined 5 species of crayfishes—Procambarus acutus (White River Crayfish), Orconectes limosus (Spinycheek Crayfish), Orconectes propinquus (Northern Clearwater Crayfish), Cambarus bartonii (Common Crayfish), and Cambarus robustus (Big Water Crayfish)—from 3 counties in New York (Saratoga, Orange, and Tompkins) and 8 counties in New Jersey (Essex, Sussex, Atlantic, Burlington, Camden, Cumberland, Gloucester, and Ocean). We recovered 2 species of entocytherid ostracods: Donnaldsoncythere cayugaensis and Donnaldsoncythere donnaldsonensis. Records from our study expand the known range of D. cayuagensis and fill in gaps in the known range of D. donnaldsonensis.

Life history of Cambarus bartonii carinirostris in northern West Virginia.

Crayfishes are essential constituents in maintaining freshwater ecosystems, yet little is known about them. The goal of this study was to better understand the ecology of a common Appalachian secondary burrowing crayfish, Cambarus bartonii carinirostris (Rock Crawfish), by achieving the first complete life history study of this species. Understanding C. b. carinirostris ecology will help aid in conservation and protection of closely related imperiled taxa by discovering unknown biological behaviors of secondary burrowing crayfish. Collections of C. b. carinirostris were conducted in Nettle Run, a first to second–order stream, of West Liberty University’s Campus Woods, Ohio County, West Virginia. Each site represented in the study for a given day and time consisted a 20 meter reach of the stream, where potential habitat within each reach was disrupted and individuals were captured by dip net or by hand. So far, this study has consisted of catching, measuring, sexing, and determining the relative age of each crayfish as well as noting their preferred habitat. Important life history variables such as growth rates, maturity, and other important reproductive patterns can be determined in conjunction with the morphometric measurements of all individuals captured.

Ontogenetic shifts in a freshwater cleaning symbiosis: consequences for hosts and their symbionts.

Animal fitness is influenced by diverse assemblages of internal and external symbionts. These assemblages often change throughout host ontogeny, but the mechanisms that underlie these changes and their consequences for host fitness are seldom revealed. Here we examine a cleaning symbiosis between crayfish and an assemblage of ectosymbiotic branchiobdellidan worms to uncover what mechanisms drive changes in symbiont composition during host ontogeny and the consequences of these changes for both the host and symbionts. In surveys of a North Carolina river, the dominant worm species shifted from Cambarincola philadelphicus to Cambarincola ingens as crayfish (Cambarus bartonii) increased in size. We demonstrate that this shift is a function of host regulation by small crayfish and exclusion by a dominant symbiont on large crayfish. In a controlled lab experiment, small crayfish often removed their symbionts but C. ingens was removed at a higher rate than C. philadelphicus. In contrast, C. ingens had higher survivorship and reproduction than C. philadelphicus on large crayfish. We also measured the effect of each worm species on crayfish growth through ontogeny; neither worm species had an effect on small crayfish but both species had similar positive effects on the growth of large crayfish relative to controls. Evidence from another experiment suggested that intraguild predation by C. ingens caused a decline in C. philadelphicus on large crayfish. We have shown that shifts in partner fitness are a function of host size and that these shifts can involve the succession of symbionts. Further, our results suggest that changes in the outcome of symbioses can remain robust throughout host ontogeny despite interactive mechanisms that lead to shifts in symbiont community structure.

Variation in native crayfish agonistic response to the invasion of the rusty crayfish Orconectes rusticus (Girard, 1852)

The consequences of biological invasions warrant continued research on the mechanisms underlying the spread of exotic species, yet interspecific behavioral interactions are largely overlooked as a contributing factor or consequence of introductions of exotic species. Our study evaluates how native crayfish species, Cambarus bartonii (Fabricius, 1798) and Orconectes propinquus (Girard, 1852), respond behaviorally to the invasion of the rusty crayfish, Orconectes rusticus (Girard, 1852) in the Upper Susquehanna River Basin, NY, USA using experiments in a semi-natural setting. We found significant effects of species, sex, year, novelty to invasion, and abiotic environment on the proportion of time native crayfish species exhibited agonistic behavior toward invading rusty crayfish. Cambarus bartonii females were generally more aggressive than males, particularly in year two, but the opposite was true for O. propinquus as males were more aggressive than females. Behavioral variation in recipient crayfish communities is a potential mechanism influencing the spread of introduced crayfishes although future study is necessary to assess the relative extent of such influence. The mechanisms driving the spread of invasive species are clearly complex and interactive, but the development of effective management plans is limited by the completeness of our understanding, which thus far has been lacking a substantial ethological component.

Altered pH and reduced calcium levels drive near extirpation of native crayfish,Cambarus bartonii, in Algonquin Park, Ontario, Canada

Multiple natural and anthropogenic stressors pose a serious threat to the health and diversity of biological communities. A growing body of research suggests that one consequence of these stressors has been a regional-scale loss of crayfish populations across south-central Ontario. The mechanisms contributing to the imperilment of crayfish probably include historical acidification and metal contamination, shoreline development and habitat loss, increased water temperature, declining [Ca] in lake water, and invasion by nonnative species (i.e., Smallmouth Bass and the rusty crayfish). Long-term monitoring data of crayfish populations in Algonquin Provincial Park (Ontario) have documented marked declines in Cambarus bartonii abundance despite the relatively isolated nature of the study lakes. Furthermore, monitoring data indicate that the onset of this decline may predate the monitoring record, thereby creating a need for the use of paleolimnological techniques to infer past conditions. We used a multiple proxy approach (i.e., diatoms and cladocerans) to reconstruct key environmental variables (e.g., pH) and long-term changes in lake chemistry (e.g., [Ca]) as they pertain to crayfish population loss. We found that interactions between pH and [Ca] have led to the decline in crayfish abundance and to the continued lack of recovery of these populations. Furthermore, lake-water [Ca] in all 4 Algonquin Park lakes are now <2.0 mg/L, the lowest hypothesized requirement for freshwater crayfish (2–10 mg/L), suggesting that short-term recovery of crayfish populations is unlikely, despite pH recovery.

Physical habitat and water quality correlates of crayfish distributions in a mined watershed

In mined watersheds, water quality alters aquatic faunas, but few studies have focused on associations between stream habitat and crayfish distributions. We examined associations of water quality and physical habitat quality on presence/ absence of six crayfish species in the upper Kanawha River drainage of southern West Virginia, USA, a region with a long history of surface and mountaintop removal mining of coal. Data supported an association of physical habitat quality with the presence of four species (Cambarus carinirostris, Cambarus robustus, Cambarus cf. sciotensis, and Orconectes sanbornii). Cambarus bartonii cavatus and the non-native Orco- nectes virilis were associated with lower quality physical habitat than that of the other four species. Relative to other species, C. b. cavatus was associated with the lowest conductivity values, whereas O. virilis was associated with the highest conductivity values. Secondary and tertiary burrowers were generally associated with relatively high-quality physical hab- itat. However, C. b. cavatus, a crayfish known to burrow extensively in headwater streams, was associ- ated with the lowest quality physical habitat. Physical habitat quality was generally supported over stream conductivity as a variable influencing crayfish distri- butions. Our data demonstrate the importance of stream habitat quality when assessing crayfish assem- blages within mined watersheds.

Evaluating the effect of lake calcium concentration on the acquisition of carapace calcium by freshwater crayfish

Aquatic systems in many parts of the world, including those on the Canadian Shield in central Ontario, Canada, are facing severe declines in aquatic calcium (Ca). The relationship between the Ca content of the carapace of freshwater crayfish, Orconectes virilis, O. rusticus and Cambarus bartonii, and lake Ca concentration was statistically evaluated across a broad [Ca] range in south-central Ontario. Carapace Ca content was significantly positively related to lake [Ca] in O. virilis but not C. bartonii or O. rusticus, probably because the latter two were only sampled over a comparatively small range of lake [Ca]. We evaluated additional variation in carapace Ca content potentially explained by the characteristics of O. virilis individuals, including size (carapace length), sex, and hardness (rigidity), using multiple linear regression. The carapace Ca content of O. virilis was significantly positively related to the hardness of the carapace, and to a lesser extent the size of the individual. For O. virilis, lake [Ca] appears to limit carapace Ca acquisition below approximately 8 mg l−1. O. virilis is therefore experiencing stress due to low [Ca] in the majority of soft-water boreal lakes where it occurs because they are undergoing [Ca] decline.

Crayfish Fauna of Southeastern Pennsylvania: Distributions, Ecology, and Changes Over the Last Century

Abstract We describe the current distributions and relative abundances of southeastern Pennsylvania's crayfish; changes in the region's crayfish fauna over the last century; and, where pertinent, the relationship of the current fauna to site-specific characteristics, basin-wide attributes, and exotic crayfish. The crayfish fauna currently inhabiting the region bears little resemblance to the historical assemblage. Whereas historical surveys yielded Orconectes limosus and Cambarus bartonii, both native species, recent collections produced eight species including five exotics. Many areas occupied by exotic Orconectes no longer support O. limosus. Cambarus bartonii was found in a number of invaded systems, but was typically a minor component of the crayfish community and may not be able to persist in those systems indefinitely. The distribution of Cambarus (Puncticambarus) sp., an undescribed member of the Cambarus acuminatus complex, was extremely limited, with populations only found in four streams, all of...

Nuclear DNA content variation associated with muscle fiber hypertrophic growth in decapod crustaceans

We tested the hypothesis that hypertrophic muscle growth in decapod crustaceans is associated with increases in both the number of nuclei per fiber and nuclear DNA content. The DNA-localizing fluorochrome DAPI (4',6-diamidino-2-phenylindole) and chicken erythrocyte standards were used with static microspectrophotometry and image analysis to estimate nuclear DNA content in hemocytes and muscle fibers from eight decapod crustacean species: Farfantepenaeus aztecus, Palaemonetes pugio, Panulirus argus, Homarus americanus, Procambarus clarkii, Cambarus bartonii, Callinectes sapidus, and Menippe mercenaria. Mean diploid (2C) values in hemocytes ranged from 3.6 to 11.7 pg. Hemocyte 2C estimates were used to extrapolate ploidy level in the multinucleated skeletal muscle tissue of juvenile and adult animals. Across all species, mean muscle fiber diameters from adult animals were significantly larger than those in juveniles, and nuclear domains were greater in larger fibers. The number of nuclei per fiber increased with increasing fiber size, as hypothesized. Maximum nuclear DNA content per species in muscle ranged from 4C to 32C, consistent with endopolyploidy. Two patterns of body- and fiber-size-dependent shifts in ploidy were observed: four species had a significantly higher ploidy in the larger fibers of adults, while three species exhibited a significantly lower ploidy in adults than in juveniles. Thus, across species, there was no systematic relationship between nuclear domain size and nuclear DNA content.

The Extirpation of Orconectes limosus (Spinycheek Crayfish) Populations in West Virginia

Abstract Introductions of nonnative crayfish species have resulted in the global decline of native crayfish populations, including those in North America. Historically, the North American range of Orconectes limosus (Spinycheek Crayfish) extended from Maine, southward into northern Virginia, including West Virginia's eastern panhandle. A 1988–1989 survey of the eastern panhandle of West Virginia resulted in the capture of only 14 O. limosus, but an abundance of the nonnative Orconectes virilis (Virile Crayfish). These data along with additional unpublished accounts of declines of O. limosus populations prompted our survey of eastern West Virginia. In 2005 and 2006, crayfishes were collected from streams within the West Virginia range of the O. limosus, including historic capture locations. Our collection of 600 individuals comprised crayfishes from 3 species: O. virilis, Orconectes obscurus (Allegheny Crayfish), and Cambarus bartonii bartonii (Common Crayfish). The nonnative O. virilis was present at 26 o...

Influence of Elevated Temperature and Acid Mine Drainage on Mortality of the Crayfish Cambarus bartonii

ABSTRACT Effects of elevated temperature and acid mine drainage (AMD) on crayfish mortality were investigated in the Stony River, Grant County, West Virginia. During summers 2003 and 2004, four-week in situ bioassays were performed along a thermal and AMD gradient with the native crayfish Cambarus bartonii. Crayfish mortality was analyzed in conjunction with temperature and AMD related variables (pH, specific conductivity). Mortality was significantly higher (48–88%) at sites with high temperatures during 2003 (max = 33.0°C), but no significant differences were observed in 2004 (max = 32.0°C). Temperatures were higher in 2003 than 2004 due to increased discharge from a cooling reservoir flowing into the river. Additionally, duration of high temperature was approximately four days in 2003 as compared with only one day in 2004. No significant relationship between acid mine drainage variables and crayfish mortality was apparent.