Common Carp Abundance Research Articles

Evaluating potential competitive bottlenecks between invasive common carp and native bluegill and yellow perch

AbstractProcesses influencing fish recruitment are often highly complex and inherently difficult to understand. Invasive species may complicate recruitment through habitat and food web modifications resulting in competitive bottlenecks. Common carp Cyprinus carpio have been distributed worldwide, and their introductions have resulted in destructive effects on aquatic ecosystems and food web dynamics. Common carp are highly fecund, and high densities of age‐0 carp may occur in some years that may reduce invertebrate prey resources and adversely affect native age‐0 fishes. We used enclosures and field observations to examine potential effects of age‐0 common carp on growth and survival of age‐0 yellow perch Perca flavescens and bluegill Lepomis macrochirus. Yellow perch and bluegill were stocked into enclosures with and without common carp (31 fish/m3) using a substitution experimental design, and fish growth and survival and invertebrate prey resources were assessed. Common carp reduced growth of yellow perch but not bluegill and did not affect survival of either species in mesocosms. Next, we used patterns of common carp, bluegill, and yellow perch abundance and total length across 38 lake‐years to evaluate potential interspecific interactions in natural systems. Age‐0 common carp abundance was not negatively related to size or abundance of bluegill or yellow perch. However, adult common carp and age‐0 yellow perch abundance were inversely related, suggesting a potential competitive bottleneck. Thus, age‐0 common carp may suppress growth of yellow perch when prey is limited, but adult common carp may have larger effects than early life stages on native juvenile fishes.

Using Boat Electrofishing to Estimate the Abundance of Invasive Common Carp in Small Midwestern Lakes

AbstractThe common carp Cyprinus carpio is among the most invasive fish worldwide, but practical methods for estimating its abundance have not yet been developed. Particularly needed are methods that can accurately assess low densities of common carp to enact proactive management strategies before populations reach damaging levels. In this study we tested whether the density of adult common carp in small Minnesota lakes could be accurately predicted from their catch rates using boat electrofishing. We used mark and recapture to estimate the abundance of common carp in eight Midwestern lakes with a wide range of common carp densities (13–400 carp/ha), while also surveying each lake using boat electrofishing. In addition, we reduced common carp abundance by up to 90% in two lakes to test whether this was accompanied by a similar drop in electrofishing catch rates. A regression analysis showed that electrofishing catch rates increased linearly with increasing densities of common carp. A cross‐validation procedure showed that boat electrofishing can accurately estimate common carp densities; however, we observed a tendency to overestimate low densities and underestimate high densities. Our results suggest that electrofishing surveys can be routinely employed to estimate common carp densities in small lakes.Received December 13, 2011; accepted April 26, 2012

Engineered water level management facilitates recruitment of non-native common carp, Cyprinus carpio, in a regulated lowland river

River regulation can advantage non-native aquatic biota at the expense of native species. Nevertheless, flow regulating structures are sometimes used with the aim of achieving positive environmental outcomes in aquatic ecosystems. In the lower River Murray, Australia, drought-induced water level recession and acid sulfate soil exposure prompted the construction of an earthen levee, isolating a section of river channel (the Goolwa weir pool (GWP)) within which water levels were managed to mitigate a risk of water body acidification. The present study aimed to determine the impact of water level management on the fish community by investigating variation in species abundance and recruitment between sites subject to water level management in the GWP and unmanaged sites in Lake Alexandrina. Prior to levee construction, in August 2009, the abundance of the non-native common carp was similar in the GWP and Lake Alexandrina. Following water level management, in December 2009 and April 2010, the abundance of common carp in the GWP was approximately 1000 and 250 times greater than abundance in Lake Alexandrina, as a result of recruitment of young-of-year fish. No native freshwater species were significantly more abundant in the GWP in August 2009, December 2009 or April 2010. The results of this study suggest that the isolation of a river reach and a managed rise in water level facilitated spawning and recruitment of a non-native fish species. As such, the ecological benefits and risks of restoration and mitigation projects that involve the construction of flow regulating structures and water level management should be carefully considered.

Simulated Population Responses of Common Carp to Commercial Exploitation

AbstractCommon carp Cyprinus carpio is a widespread invasive species that can become highly abundant and have deleterious ecosystem effects. Thus, aquatic resource managers are interested in controlling common carp populations, but control is difficult, in part, because of the inherent uncertainty as to how populations respond to exploitation. To better understand this response, we evaluated the population dynamics (recruitment, growth, and mortality) of common carp in three natural lakes in eastern South Dakota. Common carp exhibited similar population dynamics across these three systems, which were characterized by consistent recruitment (ages 3–15 being present), fast growth (K = 0.37–0.59), and low mortality (A = 1–7%). We then modeled the effects of commercial exploitation on size structure, abundance, and egg production to determine its utility as a management tool to control populations. All three populations responded similarly to exploitation simulations in which a 575‐mm length restriction represented commercial gear selectivity. Simulated common carp size structure declined modestly (9–37%) in all simulations. The abundance of common carp declined dramatically (28–56% of starting levels) at low levels of exploitation (0–20%), but exploitation greater than 40% had little additive effect, the final populations only being reduced 49–79% despite high exploitation (>90%). At a moderate level of exploitation (40%), maximum lifetime egg production was reduced to 77–89% of starting levels, indicating the potential for recruitment overfishing. Exploitation further reduced common carp size structure, abundance, and egg production when simulations were not size selective. Our results provide insights into the ways in which common carp populations may respond to exploitation. Although commercial exploitation may be able to partially control populations, an integrated removal approach that removes all sizes of common carp has a greater chance of controlling population abundance and reducing the perturbations induced by this invasive species.Received July 23, 2010; accepted January 6, 2011

Relationships among invasive common carp, native fishes and physicochemical characteristics in upper Midwest (USA) lakes

Abstract – Common carp Cyprinus carpio is a widespread invasive species that, in high abundance, can impose numerous deleterious effects in aquatic ecosystems. Common carp increase turbidity and nutrient availability while reducing invertebrate prey resources and aquatic macrophytes, transforming shallow lakes from the clear‐ to turbid‐water state. However, potential effects of common carp on native fish communities have received limited attention. We evaluated the relationships among relative abundances of nine native fishes and common carp for 81 lakes in eastern South Dakota and their associated physicochemical characteristics. Inverse threshold relationships among relative abundances of native fishes and common carp were identified for black bullhead Ameiurus melas, black crappie Pomoxis nigromaculatus, bluegill Lepomis macrochirus, white bass Morone chrysops and northern pike Esox lucius, while marginally significant relationships were detected for largemouth bass Micropterus salmoides and smallmouth bass M. dolomieu. Lakes where common carp relative abundance exceeded 0.6 fish per net night had low abundance of native fishes, whereas lower abundance of common carp resulted in variable abundance of native fishes. Lakes with abundance of common carp surpassing 0.6 fish per net night were also characterised by larger surface areas and watersheds and impaired water quality (higher dissolved solids and chlorophyll a concentrations and lower secchi depth). Our results are consistent with the biotic‐abiotic constraining hypothesis that proposes biotic factors can regulate fish populations regardless of abiotic conditions. Thus, common carp abundance may need to be reduced and sustained below ecological thresholds to improve water quality and increase abundance of native fishes.

Spatial variability of common carp populations in relation to lake morphology and physicochemical parameters in the upper Midwest United States

Weber MJ, Brown ML, Willis DW. Spatial variability of common carp populations in relation to lake morphology and physicochemical parameters in the upper Midwest United States. Ecology of Freshwater Fish 2010: 19: 555–565. © 2010 John Wiley & Sons A/SAbstract – Common carp (Cyprinus carpio) is a widespread invasive species that is tolerant of a wide range of environmental conditions. Despite the circumpolar distribution of the species, limited information is available describing factors related to spatial variation in population characteristics. Eighty‐four lakes and impoundments in the upper Midwest United States were sampled to investigate the relationships of common carp relative abundance with size structure, condition and growth rates. We also investigated abiotic factors (lake morphology, physical solids and water quality) that may broadly influence common carp populations. Common carp size structure and condition were inversely related to relative abundance. Common carp relative abundance increased and size structure shifted to smaller individuals with increased lake depth, whereas lake surface area, watershed:surface area ratio and physical solids were also important in explaining common carp abundance and size structure. Common carp condition was best explained by water quality parameters and increased with metrics of lake productivity. We conclude that knowledge of factors associated with variation in common carp populations among lakes provides insights into the autecology and broad provisions for management of this generalist invasive species.

Common Carp Distribution, Movements, and Habitat Use in a River Impounded by Multiple Low‐Head Dams

AbstractThe common carp Cyprinus carpio is an introduced species that is abundant in many impounded rivers. We assessed habitat conditions and common carp abundance in three flowing sites and three impounded sites of the Fox River, Illinois, to examine factors that influence the success of common carp in these systems. Radiotelemetry was used to determine long‐term movement and habitat use patterns of common carp among flowing and impounded areas. Impounded areas were wider and deeper than flowing areas and had lower current velocities, smaller substrates, and lower abundances of cover. Common carp were found at all sites during summer, with catch rates being similar between flowing and impounded areas. The proportion of the fish assemblage consisting of common carp was similar between flowing and impounded areas during two of the study years but was higher in impounded areas than in flowing areas during the other two years. Radio‐tagged common carp displayed a variety of movement patterns but used impounded areas most frequently during all seasons. Many common carp were always located in impounded areas, but some individuals moved upstream into flowing areas in spring and summer and returned to impounded areas by fall. Common carp positively selected for intermediate depths and low current velocities. Few consistent relationships were apparent in the use of substrate categories, but common carp selected most strongly for wood cover. Management activities targeting common carp should account for movements of this species among different habitat types and should focus on specific aspects of common carp life history. Dam removal or modification may also lead to declines in common carp abundance in some rivers.

Distribution of common carp in a Spanish reservoir in relation to thermal loading from a nuclear power plant

Arrocampo Reservoir is used as a cooling basin for a nuclear power plant located in southern Europe. Its annual mean temperature is about 30 °C with maxims that achieved 41.5 °C near the hot water effluent. Common carp ( Cyprinus carpio, Linnaeus 1758) is the dominant pelagic fish species in this reservoir. Hydroacoustic surveys were conducted bimonthly over 9 years to characterize common carp abundance and distribution in the reservoir on an annual and seasonal temporal scale. Mean fish density during the period was 0.029 fish m −3, varying from a maximum of 0.038 in 2003 to a minimum of 0.012 in 1998. There were no significant differences in the mean fish density among years. Each year, fish distribution showed significant seasonal variation. Carp were homogeneously distributed during autumn and spring; in winter carp occupied warmer outfall areas, whereas in summer, fish were distributed in the coldest area of the reservoir (dam area) but avoided the warm outfall area. These seasonal tendencies of carp distribution was repeated every years. Behavioural reaction appears to be particularly important in explain carp distribution in this reservoir.

Managing a Migratory Pest Species: A Selective Trap for Common Carp

AbstractTrapped common carp Cyprinus carpio display a pronounced escape behavior of jumping out of the water; this behavior is not exhibited by most Australian native fishes. Hence, there appears to be an important opportunity to exploit the unique jumping behavior of nonnative common carp to aid selective removal. We report on the Williams cage, a simple device that automatically separates jumping common carp from nonjumping fish. Between November 2002 and April 2005, the Williams cage was tested at Torrumbarry Weir fishway on the Murray River, Victoria, Australia, and trapped fish were counted every 24 h. The Williams cage successfully separated 88% of adult common carp into a confinement area. In contrast, more than 99.9% of 8,031 native fish passed through the Williams cage and exited the fishway. The Williams cage may provide a method for controlling dispersal and abundance of common carp and may be applicable to other nuisance fish species.

The effects of limnological features on fish assemblages of 14 Spanish reservoirs

Abstract – The relationship of water quality and fish assemblages has been poorly documented in European reservoirs, despite being important for water management and ecological monitoring. We sampled the fish assemblages of 14 Spanish reservoirs by boat electrofishing in the littoral and multi‐mesh gillnets in the limnetic zone. Simultaneously, we assembled eight physical descriptors and we measured 20 water quality features of the reservoirs. Multivariate analysis (ordination methods and generalised additive models) showed that altitude and trophic state (indicated by chlorophyll or nutrient concentrations) independently explained most of the variation of fish assemblages in these reservoirs. The most eutrophic reservoirs were dominated by common carp (Cyprinus carpio) whereas oligotrophic reservoirs presented other fish species intolerant to pollution rather native (such as brown trout, Salmo trutta). The absolute and relative abundance of common carp was strongly related to the trophic state of the reservoir and 40% of its variation was explained by total phosphorous concentration. Despite clear changes in species composition, there was no significant effect of water quality on overall fish richness or Shannon's diversity, suggesting that for such low richness assemblages species composition is a better indicator of cultural eutrophication of reservoirs than fish diversity.

Physicochemical and Biological Influences on Black Bullhead Populations in Eastern South Dakota Glacial Lakes

ABSTRACT Lake and fish survey data (1991–1992) were compiled for 23 eastern South Dakota natural lakes to provide a basis for preliminary investigation of black bullhead (Ameiurus melas) populations. Survey data contained numerous physical and chemical variables describing lake environments and relative abundance and sue structure of the primary fish species present. Analyses indicated that abundance of black bullheads increased with decreasing lake size (area, depth and volume), increasing nutrients (e.g., total and dissolved phosphorus), and decreasing transparency. Overall, models of biotic variables indicated that black bullhead abundance was negatively associated with abundance of bigmouth buffalo (Ictiobus cyprinellus) and walleyes (Stizostedion vitreum), but positively associated with northern pike (Esox lucius) and common carp (Cyprinus carpio) abundance. Black bullhead sue structure was inversely related to the abundance of common carp, northern pike and yellow perch (Perca flavescens). Black bullhead population size structure was not related to any physicochemical variables. There appeared to be no regulation of black bullhead abundance or size structure by population size structures of other species.

Changes in the Habitat and Fish Community of the Milwaukee River, Wisconsin, Following Removal of the Woolen Mills Dam

We evaluated the response of fish habitat, biotic integrity, and populations of smallmouth bass Micropterus dolomieu and common carp Cyprinus carpio to the 1988 removal of the low-head Woolen Mills Dam from the Milwaukee River. After dam removal, instream habitat improvement work was done on a portion of river within the former impoundment, and a short reach just below the dam site was rerouted for bridge construction. Before dam removal in 1988, the two stations in the impounded reach of the river had fair habitat quality, few smallmouth bass, abundant common carp, and poor biotic integrity. Five years after dam removal, habitat quality was good to excellent, smallmouth bass abundance and biomass had increased substantially, common carp abundance and biomass had declined dramatically, and biotic integrity was good. A reference station on the nearby North Branch of the Milwaukee River had few major changes over the same time period, although common carp abundance and biomass did decline somewhat. Stations upstream and downstream of the impounded reach also experienced moderate declines in common carp populations, and the upstream station had a major increase in smallmouth bass abundance and biomass. Changes in size structure suggested that the smallmouth bass increases in the impounded and upstream stations were caused by increased recruitment rather than by permanent migration of fish from other areas. Habitat quality within the impounded reach increased more and faster in the station with instream improvement work, but the station without work also showed substantial gains in habitat quality through natural channel recovery processes. The station downstream from the dam experienced major declines in its smallmouth bass population and biotic integrity during channel rerouting in 1990. However, by 1993, both attributes had returned to 1988–1989 levels. We conclude that dam removal benefited habitat, fisheries potential, and biotic integrity in the Milwaukee River. Direct habitat improvement activities enhanced these benefits, but natural habitat recovery and removal of the dam as a barrier to fish movement accounted for many of the improvements we observed.

Indexing of common carp populations in large palustrine wetlands of the Northern Plains

We evaluated gill netting and trapnetting as tools to index relative abundance of common carp (Cyprinus carpio) in two national wildlife reguges in North and South Dakota. Trap net catch rates were low (1.4/net night) and required much effort to obtain reliable sample sizes. Gill nets had mesh sizes of 51, 76, and 102 mm (bar measure). Each gill net had only one mesh size and three nets were thus needed to sample the entire length range of adult common carp for one unit of effort (one complement). The mesh sizes were suitable for capturing 30-cm and longer common carp and precluded the need for intermediate mesh sizes. Catch rates (number of common carp caught per net complement night) from May samples consistently had lower coefficients of variation than samples in June, July, or August. Based on the mean and variance from our sampling, 125–684 net complement nights would provide reliable catch-rate data at the 95% confidence level. More realistically, 8–43 net complement nights would provide reliable estimates at the 80% confidence level. Accordingly, we recommend that an optimum sampling schedule would involve sampling in May and that each gill net have all three mesh sizes within one net.