Article

Predatory Efficiency and Prey Selection - Interactions between Pike Esox-Lucius, Lucius, Perch Perca-Fluviatilis and Rudd Scardinus-Erythrophthalmus

October 1989
Oikos 56(2):149-156

October 1989
56(2):149-156

DOI:10.2307/3565330

Authors:

Peter Eklöv

Uppsala University

Stellan Hamrin

save the baltic salmon

Pike preferred the soft-rayed rudd over the spiny-rayed perch in open water. At low vegetation density the prey species were selected equally and at dense vegetation the more available perch were selected over rudd. In the low productivity Lake Ornanas, Sweden, rudd were mainly found in the inner part of the littoral zone, while perch were found in the outer part and in the pelagic zone. The main potential piscivore found in the littoral zone was pike. This suggests that rudd and perch habitat distribution is influenced by pike predation where the prey species either can use physical complexity or morphological defence as antipredator devices. Consequently rudd is expected to take cover in the vegetation to which it seems to be better adapted while the spiny-rayed perch can withstand pike predation and stay in the more open habitat. -from Authors

Feeding biology of pike, Esox lucius L., 1758 inhabiting Lake Ladik, Turkey

Article

Full-text available

Jan 2018

This study was conducted to determine feeding biology and prey selection of pike inhabiting Lake Ladik (Ladik, Samsun). Sampling was carried out monthly between November 2009 and October 2010. The stomachs of 204 individuals were analyzed and 32.35% of them were empty. Feeding intensity varied by seasons and length group. Fullness index values were the lowest during summer and in large sized pike, while feeding intensity was the highest during autumn and in small specimens. Prey fish dominated the diet in all length groups throughout the year whereas feeding on invertebrates was limited to small pikes. For small, medium and large length individuals, the most preferred prey fish were Perca fluviatilis (Va = 0.139, χ2 = 3.86, P < 0.05), Chondrostoma regium (Va = 0.169, χ2 = 5.752, P < 0.05) and Abramis brama (Va = 0.337, χ2 = 22.731, P < 0.01), respectively. The pike exhibited a specialist feeding strategy on fish. The most important food items of pike were Scardinius erythrophthalmus, Perca fluviatilis and Abramis brama, respectively. Also, it was determined that there were significant positive relationships between prey dimensions-predator size and predator mouth sizes-predator length. © Published by Central Fisheries Research Institute (CFRI) Trabzon, Turkey.

Effect of Predator Size and Prey Characteristics on Piscivory of Juvenile Largemouth Bass

Article

Full-text available

Jun 2015

Largemouth Bass Micropterus salmoides undergo a diet shift to fish prey during the juvenile stage, but mechanisms influencing piscivorous behavior are largely unknown. In laboratory experiments, we examined ontogenetic effects of predator and prey size on piscivory of juvenile Largemouth Bass. Prey size preferences were determined in aquaria experiments by introducing multiple size ranges of either Bluegill Lepomis macrochirus, Gizzard Shad Dorosoma cepedianum, or Fathead Minnow Pimephales promelas with a Largemouth Bass from one of three length-classes (30, 50, and 75 mm TL). For Gizzard Shad, Largemouth Bass most often selected larger sizes (33-65% of Largemouth Bass length) than in experiments with either Fathead Minnow or Bluegill (25-48%). Although an optimal foraging model (handling time/prey dry mass) predicted most prey sizes chosen, Largemouth Bass, with their large gape, chose slightly larger prey than predicted for all three prey species. Using optimal-sized prey, we further investigated differential prey vulnerability and development of foraging behavior of juvenile Largemouth Bass (30-75 mm) in experiments conducted in a 750-L tank. Prey increased schooling and distance maintained from predators as they grew, but all sizes of Largemouth Bass foraged similarly, suggesting differences in predation success were due to prey morphology and species-specific behavioral responses of prey. Results of our study can provide better predictions for prey consumption patterns of piscivorous juvenile Largemouth Bass in field settings.

Sexual size dimorphism of two common European percid fish: linkage with spatial distribution and diet

Article

Full-text available

May 2022
HYDROBIOLOGIA

Many fish species exhibit female-biased size dimorphism that may lead to spatial segregation of sexes. We selected two common European percids (Percidae, European perch Perca fluviatilis and ruffe Gymnocephalus cernua) differing in total body size, reproduction mode, habitat use and diurnal activity, to test whether they display size dimorphism and its effect on habitat use and diet. Females were significantly larger than equally old males (by 76% in perch, 23% in ruffe). No differences in habitat use by sexes were found along depth and longitudinal gradients of reservoir or between inshore and offshore habitats. Perch females had fuller guts, but both sexes were equally likely to consume same prey items (Leptodora kindtii, Daphnia spp., Chironomidae larvae, fish). Both sexes of ruffe had similar stomachs fullness, but females preferred L. kindtii and males Asellus aquaticus. In summary, perch and ruffe show strong female-biased size dimorphism, but sexes do not segregate spatially. Their unequal sex-specific dietary demands are satisfied by higher feeding rate of female perch and by preference for different prey items in ruffe. The magnitude of dimorphism was related to species body size and reproduction mode being larger in larger species and in total spawner (perch).

Shifts in diet of an apex predator following the colonisation of an invasive fish

Article

Full-text available

Jul 2019
HYDROBIOLOGIA

Roach is an invasive cyprinid fish species that has been introduced to many Irish lakes, causing broad changes in fish community dynamics. This paper examines whether roach invasion is associated with temporal change in the diet of pike in colonised systems. The seasonal diet of pike in three Irish lakes was compared between a historical (pre-roach) data set collated on a monthly basis in the 1960s and 1970s, and recent samples collected monthly over 1 year in 2016–2017. Statistical models indicated a significant increase between sampling periods in the probability of observing cyprinids in pike stomachs, and corresponding significant decreases in the probability of observing perch or brown trout. Small pike were significantly less likely than large pike to have salmonid prey in their stomach. There were seasonal effects on diet, with invertebrates and sticklebacks being consumed more in Winter–Spring compared to Autumn–Summer. In the recent period, prey selection indices indicated positive selection for roach and negative selection for perch; indices for trout tended towards neutrality. The dietary shift in pike following the establishment of roach may have alleviated predation pressure on native trout (and perch), with implications for food web structure in invaded lakes.

Spatial occupation strategies in lacustris systems: ichtyofauna reactions in a overheated and unstratified reservoir

Article

Full-text available

Nov 2005

Samuel Dembski

The study was conducted in an artificial reservoir, adjacent to a nuclear power plant, in which water temperatures are cool in the winter (8.2 – 12.4°C) and rise early in the spring (April : 14.7°C) nearly 5°C and 3°C over the temperature of its tributary (Moselle river), respectively. The absence of stratification (neither thermocline nor oxycline exist) and the constant water level provided a unique opportunity to observed fish distribution with low abiotic constraints. In one hand, temporal and spatial distributions of the fish community were studied in both littoral and pelagic area. The time survey separated two major groups of young of the year (YOY) according to their time of appearance; the first represented the progeny of early-spring spawning species whereas the second resulted from later-spawning species. Ontogenetic niche shifts of coexisting species were appreciated and for example during late spring and summer, the smallest white bream YOY (LT < 20 mm) were restricted to complex habitats whereas those of pumpkinseed occupied all available habitats. Growing white bream progressively migrated to open water before reaching pelagic areas. There, the vertical distribution of fish was studied using gill net time series. Seasonal and species-specific distribution patterns were highlighted. During the autumn, many species were sampled in deeper water whereas pumpkinseed was the only one sampled in abundance in the littoral zone. Pumpkinseed introduction success might be explained by both its late hatching and its opportunistic strategy in habitat selection enabling it to exploit space left vacant. In the other hand, life history reactions of fish exposed to heated waters were studied particularly in the pumpkinseed population. Fast growth among young of the year, precocious maturity and short life-span were observed, in contrast to related studies. The short life span appeared to be the price paid for early maturity in breeding fish, which suffered high mortality rates just after their first reproduction. These findings should prove helpful in predicting ecological responses to climatic change.

A 15-year Study of the Spatial Distribution of Rutilus rutilus and Perca fluviatilis in Late Summer in Two Shallow Lakes With Contrasting Trophic State

Article

Full-text available

Dec 2021

Roach (Rutilus rutilus) and perch (Perca fluviatilis) are dominant species in northern-temperate lakes of Europe, their relative importance depending on trophic state and habitat complexity. We studied the habitat distribution of roach and perch over a 15-year period in two Danish lakes, Lake Væng, undergoing major changes in water clarity and macrophyte coverage, and the permanent turbid Lake Søbygård. We used multi-mesh sized gill nets in 5-6 different sections of the lakes following the same program in all years. Both species were evenly distributed in the sections and among habitats, in Lake Væng during the turbid period and in Lake Søbygård during the whole study period. During the clear-water period in Lake Væng, however, the distribution of roach and perch was uneven and the density negatively correlated with macrophyte coverage and density, but the strength of the relationship differed between the two species and between small (≤ 8 cm for roach and <10 cm for perch) and larger fish. Our results suggest that water clarity and macrophyte density were of key importance in determining roach and perch distribution in these two shallow lakes.

Modelling temperature‐driven changes in species associations across freshwater communities

Article

Full-text available

Oct 2021

Due to global climate change-induced shifts in species distributions, estimating changes in community composition through the use of Species Distribution Models has become a key management tool. Being able to determine how species associations change along environmental gradients is likely to be pivotal in exploring the magnitude of future changes in species' distributions. This is particularly important in connectivity-limited ecosystems, such as freshwater ecosystems, where increased human translocation is creating species associations over previously unseen environmental gradients. Here, we use a large-scale presence-absence dataset of freshwater fish from lakes across the Fennoscandian region in a Joint Species Distribution Model, to measure the effect of temperature on species associations. We identified a trend of negative associations between species tolerant of cold waters and those tolerant of warmer waters, as well as positive associations between several more warm-tolerant species, with these associations often shifting depending on local temperatures. Our results confirm that freshwater ecosystems can expect to see a large-scale shift towards communities dominated by more warm-tolerant species. While there remains much work to be done to predict exactly where and when local extinctions may take place, the model implemented provides a starting-point for the exploration of climate-driven community trends. This approach is especially informative in regards to determining which species associations are most central in shaping future community composition, and which areas are most vulnerable to local extinctions.

Nursery habitat characteristics of an invasive, omnivorous fish

Article

Full-text available

Dec 2021
HYDROBIOLOGIA

Understanding habitat use and reproductive biology of invasive species is essential to predicting invasions, designing early detection programs, and developing management plans. The rudd (Scardinius erythrophthalmus; Linnaeus, 1758) is an omnivorous fish native to Europe and western Asia that has been translocated to several countries in western Europe, New Zealand, North America, and Africa. However, little is known about early life history of rudd, particularly in invaded ecosystems, limiting our ability to predict invasions and create early detection and control programs. The upper Niagara River has the most abundant population of rudd in North America and has been the focus of several ecological investigations. Our study identified critical nursery habitats by determining which nearshore habitat factors were most strongly associated with presence of age-0 rudd. We found that emergent vegetation was the most important habitat characteristic associated with the presence of age-0 rudd. When emergent vegetation was not present, rudd were more likely to be present at sites with abundant submerged aquatic vegetation. Additionally, the odds of rudd presence decreased as distance to the nearest wetland increased. These findings can be used to create habitat-driven predictive models of rudd invasion and guide early detection programs for rudd outside their native range.

The hunter and the hunted-A 3D analysis of predator-prey interactions between three- spined sticklebacks (Gasterosteus aculeatus) and larvae of different prey fishes

Article

Full-text available

Aug 2021
PLOS ONE

Predator-prey interactions play a key life history role, as animals cope with changing preda-tion risk and opportunities to hunt prey. It has recently been shown that the hunting success of sticklebacks (Gasterosteus aculeatus) targeting fish larvae is dependent on both the size of the prey and the prior exposure of its species to stickleback predation. The purpose of the current study was to identify the behavioural predator-prey interactions explaining the success or failure of sticklebacks hunting larvae of three potential prey species [roach (Rutilus rutilus), perch (Perca fluviatilis) and whitefish (Coregonus wartmannii)] in a 3D environment. Trials were carried out for each prey species at four different size classes in a standardised laboratory setup and were recorded using a slow motion, stereo camera setup. 75 predator-prey interactions including both failed and successful hunts were subject to the analysis. 3D track analysis indicated that sticklebacks applied different strategies. Prey with less complex predator escape responses, i.e. whitefish larvae, were hunted using a direct but stealthy approach ending in a lunge, while the behaviourally more complex roach and perch larvae were hunted with a faster approach. A multivariate logistic regression identified that slow average speed and acceleration of the prey in the initial stages of the hunt increased the probability of stickleback success. Furthermore, predators adjusted their swimming direction more often when hunting larger whitefish compared to smaller whitefish. The results suggest that appropriate and adequately timed avoidance behaviours, which vary between prey species and ontogenetic stages, significantly increase the chances of outmanoeuvring and escaping stickleback predation. Small whitefish larvae can reach similar levels of swimming performance compared to older conspecifics, but display ineffective anti-predator behaviours, resulting in higher hunting success for sticklebacks. Thus, the development of appropriate anti-predator behaviours depending on size appears to be the crucial factor to escaping predation. PLOS ONE PLOS ONE | https://doi.org/10.1371/journal.pone.

Vulnerability of Pacific salmon to invasion of northern pike (Esox lucius) in Southcentral Alaska

Article

Full-text available

Jul 2021
PLOS ONE

The relentless role of invasive species in the extinction of native biota requires predictions of ecosystem vulnerability to inform proactive management strategies. The worldwide invasion and range expansion of predatory northern pike ( Esox lucius ) has been linked to the decline of native fishes and tools are needed to predict the vulnerability of habitats to invasion over broad geographic scales. To address this need, we coupled an intrinsic potential habitat modelling approach with a Bayesian network to evaluate the vulnerability of five culturally and economically vital species of Pacific salmon ( Oncorhynchus spp.) to invasion by northern pike. This study was conducted along 22,875 stream km in the Southcentral region of Alaska, USA. Pink salmon ( O . gorbuscha ) were the most vulnerable species, with 15.2% (2,458 km) of their calculated extent identified as “highly” vulnerable, followed closely by chum salmon ( O . keta , 14.8%; 2,557 km) and coho salmon ( O . kisutch , 14.7%; 2,536 km). Moreover, all five Pacific salmon species were highly vulnerable in 1,001 stream km of shared habitat. This simple to implement, adaptable, and cost-effective framework will allow prioritizing habitats for early detection and monitoring of invading northern pike.

The effect of LED lights on trap catches in Finnish inland fisheries

Article

Full-text available

May 2021
FISHERIES MANAG ECOL

Trap fisheries can provide catches of high quality, and unwanted bycatch can be released with high survival. Light attraction could be an effective way of increasing trap catches, but research results are largely lacking. Experiments to test the effect of LED lights in trap‐net fishing were conducted in two Finnish lakes where fishing targeted Eurasian perch Perca fluviatilis L. and roach Rutilus rutilus (L.). LED lights (white, green, red, blue and combinations) were attached inside the traps. The use of LED lights did not increase fish CPUE. Contrary to expectation, Eurasian perch catches were higher in traps without LED lights. Significant variation in CPUEs was observed, but without interaction with light treatments. The LED lights tested in this study do not increase the effectiveness of trap fishery targeting Eurasian perch and roach in Finnish lakes in the ice‐free season.

Environmental determinants of fish abundance in the littoral zone of gravel pit lakes

Article

Full-text available

Jun 2021
HYDROBIOLOGIA

The type and extent of habitats along the shoreline specify the distribution of fish in the littoral zone of lakes, but effects are likely species and size-specific and might be overwhelmed by lake-level environmental factors that drive fish abundance (e.g. trophic state). We applied a replicated transect-sampling design by electrofishing assessing fish abundance and distribution along the banks of 20 gravel pit lakes in Lower Saxony (Germany). Boosted regression trees were used to analyse the impact of different characteristic habitat types (e.g. vegetated, woody or open water zones), shoreline water depth and lake-level environmental variables on species-specific fish abundances. In contrast to earlier studies, lake-level environment and transect-level habitat type similarly influenced the abundances of differently sized fish species in the littoral zone of gravel pit lakes. The abundance of almost all fish species increased with lake productivity and extent of structured littoral habitats, mostly following non-linear relationships. Our work suggests that investments into the quality of littoral habitat, and not merely the control of nutrient inputs or other lake-level environmental factors, can promote abundance of most gravel pit lake fish species, in particular those who depend on the littoral zone for at least part of their life-cycle.

Observation of fish schooling behaviour in open-water habitat of a man-made reservoir via visual census

Thesis

Oct 2020

Michaela Holubová

The research presented in this thesis contributes to broadening of the knowledge on free-living adult fish schools and behavioural patterns in a temperate freshwater reservoir. The behaviour of fish in the pelagic zone is rather poorly studied. Naturally, schooling tendency varied between species mostly due to increasing vulnerability to predation. Heterospecificity in schools was not a rare phenomenon, mainly for vulnerable species that shared the same space and food niche with a predatory less attractive species. The individual needs fluctuate as factors might be reconsidered in short time periods and most probably are reflected in behavioural responses. Individual responses are also reflected in the distribution of the fish in the reservoir and density in particular habitat. There is a “critical density” that triggers the formation of fish schools, followed by a slowing increase in density of fish clusters (observed units). This corresponds to increasing proportion of fish in a school and declining proportion of singletons. The trend of count of clusters tended to have an upper limit that should result in constant count of fish clusters after reaching a particular fish density. In other words, fish in the habitat maintain maximal distances even when the density increases. During high density periods the distances are kept by school formation. Overall the usage of the visual census as presented, proved to be a convenient tool for observation and assessment of freshwater fish. It has been demonstrated that the method can obtain comparable results to hydroacoustic survey amounts as well as purse seining.

A Decade in Review: Alaska’s Adaptive Management of an Invasive Apex Predator

Article

Full-text available

Apr 2020

Northern pike are an invasive species in southcentral Alaska and have caused the decline and extirpation of salmonids and other native fish populations across the region. Over the last decade, adaptive management of invasive pike populations has included population suppression, eradication, outreach, angler engagement, and research to mitigate damages from pike where feasible. Pike suppression efforts have been focused in open drainages of the northern and western Cook Inlet areas, and eradication efforts have been primarily focused on the Kenai Peninsula and the municipality of Anchorage. Between 2010 and 2020, almost 40,000 pike were removed from southcentral Alaska waters as a result of suppression programs, and pike have been successfully eradicated from over 20 lakes and creeks from the Kenai Peninsula and Anchorage, nearly completing total eradication of pike from known distributions in those areas. Northern pike control actions are tailored to the unique conditions of waters prioritized for their management, and all efforts support the goal of preventing further spread of this invasive aquatic apex predator to vulnerable waters.

How long-term water level changes influence the spatial distribution of fish and other functional groups in a large shallow lake

Article

Full-text available

Mar 2020
J GREAT LAKES RES

We numerically explored the effects of long-term water level changes on biotic biomass and spatial distribution of fish in a large shallow lake. We calibrated Ecospace model (Ecopath with Ecosim modelling suite) with data from various functional groups (ranging from phytoplankton to piscivorous fish), and considered 14 different habitats. Two scenarios representing, respectively, a long-term water-level increase and decrease by 1 m were constructed and run for a period of thirty eight years (1979–2016). The results showed a very uneven spatial distribution of fish biomass in the lake, with the highest concentration in the southern basin. The 1 m decrease scenario caused a diminution in the biomass of all groups but piscivorous fish. The 1 m increase scenario saw a weak decrease in most species biomass. Consequently, in both scenarios, long-term water level changes would be generally detrimental to the lake biota. In the context of more frequent climate-induced hydrological fluctuations, we encourage the use of these simulations as effective tools for future prediction and assessment of ecosystem-based fisheries management and ecological status maintenance of shallow lakes.

Predation risk and competition affect habitat use of adult perch, Perca fluviatilis

Article

Full-text available

Feb 2020
J FISH BIOL

The aim of this study was to examine how the presence of a predator and an interspecific competitor influence the habitat use of adult perch (Perca fluviatilis; size: 15.1 ± 0.5 cm) when given the choice between two adjacent habitats. By conducting aquarium experiments, the habitat occupancy of P. fluviatilis was documented in the presence and absence of a predator (pike Esox lucius; size: 25.4 ± 2.1 cm) and a potential competitor (ruffe Gymnocephalus cernuus; size: 14.1 ± 0.3 cm) fish species. Two P. fluviatilis individuals generally shared the same habitat. In the presence of a conspecific, P. fluviatilis favoured the structurally more‐complex, artificial macrophyte habitat over the less‐structured rock and sand habitat, which in turn were used equally. In the predator‐ and competitor treatments, P. fluviatilis seemed to adapt their habitat use to the habitat occupancy of E. lucius and G. cernuus in the Macrophyte vs. Rock and, in the predator treatment, also in the Macrophyte vs. Sand habitat combination, by increasingly occupying a habitat that was used less by the predator or competitor species, respectively. This behaviour suggests that P. fluviatilis tried to avoid the other fish species by choosing a, in some cases less preferred, predator‐ or competitor‐free habitat. This study emphasizes the importance of biological interactions illustrated by the potential of predation risk and competition to structure fish communities by influencing habitat use at small spatial scales.

Using environmental DNA sampling to monitor the invasion of nonnative Esox lucius (northern pike) in the Columbia River basin, USA

Article

Full-text available

Jul 2019

Aquatic invasive species are recognized as a global threat to conservation of native species and a cost to society. To develop effective suppression and monitoring programs for invasive species, fisheries managers require accurate, affordable, and efficient tools for invasive species detection. In the U.S. Pacific Northwest, the rapid expansion of invasive Esox lucius (northern pike) poses threats to native species as well as the viability of tribal, sport, and commercial fisheries. To help monitor changes in the distribution of this species, we developed and rigorously field‐tested an environmental DNA (eDNA) assay to detect E. lucius. The assay successfully amplified tissue‐derived DNA of E. lucius from 36 locations east and west of the Continental Divide and did not amplify DNA of over 40 nontarget species. This assay was then used to assist with monitoring the distribution of invasive E. lucius in the upper Columbia River basin in Washington and Idaho. Sixty‐two eDNA samples were collected at 35 locations of known and unknown E. lucius presence. Two samples per site (one on each bank) were collected in larger waterbodies. E. lucius eDNA detections were consistent with previous observations of live fish during angler and gill‐net surveys, confirming the reliability of the eDNA assay. At two of the 35 sites, only one of the paired samples was positive for E. lucius DNA. Varying results between opposite bank samples highlight the need for increased sampling effort when the target species are at low abundance and in large waterbodies. The eDNA assay described in this paper can be used by managers to identify the presence of E. lucius, monitor their expansion in western North America, and guide E. lucius suppression projects.

Vertical movements of coastal pike (Esox lucius) — On the role of sun basking

Article

Apr 2019

Knowledge of patterns and drivers of the spatiotemporal distribution of top predatory fish is key to understand ecological dynamics and to successful management. Here, we integrated field and laboratory approaches to study vertical movements of pike (Esox lucius) in relation to season, light regimes and body temperature. We tagged pike from the Baltic Sea with data storage tags during spawning migration and retrieved them during migration the following years to obtain high‐resolution data from full year of movements. The results showed seasonal and diel patterns of activity and body temperature that conformed to distinct patterns of crepuscular activity and diel vertical migrations. The latter manifested as two different patterns, either a stationary phase in the surface water during day followed by night‐time in deeper water or vice versa. The occurrence of these two behaviours varied among individuals and within individuals among seasons. Diel vertical migration has previously not been described for this shallow‐dwelling species, but was a common and consistent behaviour among individuals in this study. We suggest that the function of the daytime surface behaviour in pike is to increase body temperature through sun basking. This thermoregulatory role of surfacing was supported by the laboratory study where individuals sought the surface layer, exposed themselves to infrared light and thereby attained body temperatures in excess of ambient water. These results support sun basking as a mechanism for heat gain and further suggest that access to sunlight in the surface layer could be an important driver of vertical migrations.

Endangered aquatic macrophytes in the diet of rudd (Scardinius erythrophthalmus)

Article

Full-text available

Feb 2019
FOLIA ZOOL

Oxbow lakes are specialised standing water bodies that often support unique macrophyte and animal communities. Between 2015 and 2016, we assessed the diet composition of adult rudd (Scardinius erythrophthalmus) in one such macrophyte-rich lake. Over 2016, we also undertook a series of feeding behaviour tests under artificial conditions, the aim being to assess whether adult rudd represent a threat to the endangered sharp-leaved pondweed (Potamogeton acutifolius). In total, we examined 100 digestive tracts of rudd feeding under natural conditions and 100 from rudd feeding under artificial conditions. Our results show that i) P. acutifolius is deliberately consumed by rudd, and ii) pondweeds, periphyton and invertebrates were the dominant dietary components in the diet. A reluctance to consume cleaned P. acutifolius suggests a link with periphyton and invertebrate consumption. While rudd clearly consume P. acutifolius, we found no evidence of any negative impact on either pondweed development or on the macrophyte community as a whole.

A comparative study of three different methods for assessing fish communities in a small eutrophic lake

Article

Nov 2018

Sound decisions on the management of fish stocks depend on knowledge about the species composition, number, biomass and size structure of existing populations. Accordingly, the ability to make solid population estimates is essential. In this study, a 2.15 ha lake was completely drained and the total number of fish was recorded and amounted to 180,915 individuals divided into seven species having a total weight of 1,395 kg. Before the draining, three commonly used methods in fish surveys were applied: multi‐mesh gillnets, point abundance sampling by electrofishing (PASE) and mark–recapture. Following the determination of the actual number and size distribution of each species, we evaluated the efficiency of the methods and found that gillnets caught a relatively high number of species (five out of seven) and thus proved to be the best tool for mapping species richness. However, gillnets were size selective towards larger individuals of perch (Perca fluviatilis) and did not catch roach (Rutilus rutilus) <5 cm. In contrast to gillnets, PASE was very effective at catching YOY fish in the shore zone but selected for larger‐sized roach. In sum, gillnetting proved to be the most accurate method for estimating species composition, PASE also being useful. Overall, mark–recapture provided relatively good estimates of population size but small‐sized (<11 cm) roach proved not to be well suited for mark–recapture surveys. We conclude that the best method(s) surveying fish stocks depends on various factors such as target species, size distribution and the purpose of the survey.

Comment to Hansson, S. et al. (2017): “Competition for the fish – fish extraction from the Baltic Sea by humans, aquatic mammals, and birds”, with special reference to cormorants, perch, and pikeperch

Article

May 2018

Hansson et al. (2017) concluded that competition between fisheries and piscivorous mammals and birds exists in the Baltic Sea, based on the estimation of biomass of the fish species consumed in the ICES subdivisions. We compared their results to the data and scientific knowledge from the coastal waters of Finland and show that local differences in fisheries, fish assemblages and abundance of predators should be taken into account to reliably assess potential competition. Hansson et al. (2017) did not include the piscivorous fish in their analysis, but these may be the most important predators. In the Archipelago Sea, for instance, the consumption by fish predators is considerably larger than that of cormorants.

Status of Northern Pearl Dace and Chrosomid Dace in Prairie Streams of Montana

Thesis

Full-text available

May 2018

Allison Stringer

Non-native Northern Pike Esox lucius are predators that negatively affect native fish assemblages, possibly including those in Montana prairie streams, where their effects had not been investigated heretofore. I compared fish assemblages of prairie streams with and without Northern Pike and other non-native predators, with a focus on three species of concern that are probably particularly susceptible to predation (Northern Pearl Dace Margariscus nachtriebi (hereafter pearl dace), Northern Redbelly Dace Chrosomus eos, and Northern Redbelly Dace × Finescale Dace hybrids C. eos × C. neogaeus [hereafter hybrid dace]). I documented fish assemblages at 140 sites across the historical distribution of Northern Redbelly Dace and hybrid dace (hereafter collectively referred to as chrosomid dace), including 88 sites in the historical distribution of pearl dace. I estimated percent declines in distribution by comparing the number of currently occupied historical streams with the total number of historical streams and then determined if co-occurrence of pearl dace or chrosomid dace with non-native predators was different than predicted by chance. I augmented my dataset with fish collections from 5 additional sources and evaluated whether sites with and without Northern Pike differed in native species richness (with a Poisson regression) or assemblage composition (with a discriminant function analysis). Pearl dace distribution declined 63.3 to 83.3%, and chrosomid dace distribution declined 32.0% to 67.2%, depending on how declines were calculated. Pearl dace almost never co-occurred with Northern Pike or non-native trout and chrosomid dace rarely co-occurred with them. Native minnow species richness was 52% lower at sites with Northern Pike than at sites without Northern Pike. Predation probably caused the observed changes. Pearl dace are at extreme risk and chrosomid dace are at moderate risk of extirpation from Montana, and non-native predators appear to be the biggest threat to their continued persistence. Exclusion of Northern Pike from drainages where they have not yet invaded will afford fisheries managers the best chance of conserving native minnows in Montana prairie streams.

Can species-specific prey responses to chemical cues explain prey susceptibility to predation?

Article

Full-text available

Apr 2018

The perception of danger represents an essential ability of prey for gaining an informational advantage over their natural enemies. Especially in complex environments or at night, animals strongly rely on chemoreception to avoid predators. The ability to recognize danger by chemical cues and subsequent adaptive responses to predation threats should generally increase prey survival. Recent findings suggest that European catfish (Silurus glanis) introduction induce changes in fish community and we tested whether the direction of change can be attributed to differences in chemical cue perception. We tested behavioral response to chemical cues using three species of freshwater fish common in European water: rudd (Scardinius erythrophthalmus), roach (Rutilus rutilus), and perch (Perca fluviatilis). Further, we conducted a prey selectivity experiment to evaluate the prey preferences of the European catfish. Roach exhibited the strongest reaction to chemical cues, rudd decreased use of refuge and perch did not alter any behavior in the experiment. These findings suggest that chemical cue perception might be behind community data change and we encourage collecting more community data of tested prey species before and after European catfish introduction to test the hypothesis. We conclude that used prey species can be used as a model species to verify whether chemical cue perception enhances prey survival.

Dry-weight energy density of prey fishes from nearshore waters of the upper Niagara River and Buffalo Harbor, New York

Article

Apr 2017
J GREAT LAKES RES

Energy density of prey fishes can affect the survival, growth, and fitness of piscivorous fishes, and these vital rates may change – for better or worse – after fish communities are altered by the establishment of new species. Invasive round goby (Neogobius melanostomus) and rudd (Scardinius erythrophthalmus) are highly abundant in the upper Niagara River and Buffalo Harbor and serve as alternative food for piscivores. However, there is a paucity of information on the energy density of native and invasive prey fishes in these waters. To better understand the energy density of available prey fishes in nearshore areas of the upper Niagara River and Buffalo Harbor, we compared the energy densities of: (1) native fishes and invasive fishes, (2) age-0 and yearling-and-older conspecific fishes, and (3) upper Niagara River and Buffalo Harbor conspecific fishes. Fishes were collected from New York waters of the upper Niagara River and Buffalo Harbor during early August through mid-September 2013. We combusted fishes in a bomb calorimeter to determine dry-weight energy densities (J/g) for two invasive and eight native species. Energy densities were dependent on an interaction between fish species and age group, and did not differ between the upper Niagara River and Buffalo Harbor. Yearling-and-older spottail shiner (Notropis hudsonius) had a significantly higher energy density than all other species examined and was the only species with a significant difference in energy density between age classes. Rudd had an energy density similar to most native fishes; and, although not significantly lower, round goby energy density was lower than most native fishes. Our energy density estimates can be used to better understand mechanisms affecting growth and condition of piscivorous fishes in the upper Niagara River and Buffalo Harbor.

Consumption of plant material by perch (Perca fluviatilis)

Article

Full-text available

Mar 2016
FOLIA ZOOL

Kevin Roche

While removing fish during reservoir biomanipulation, it was noted that the diet of normally piscivorous 5+ to 7+ perch was dominated by macrophyte fragments, with fish eggs sub-dominant. To the best of our knowledge, macrophytes have not previously been reported as a food item in perch. Here, we briefly discuss this finding and its significance for perch diet studies.

Simple assumptions predicts prey selection by piscivorous fishes

Article

Jun 2016
ECOL COMPLEX

Studies on trophic interactions permits the use of community-wide network analyses to evaluate the consequences of human interventions in natural communities. In this paper, we aimed to get insights into the underlying mechanism of prey selection for four piscivorous species, and evaluate behavioral responses to prey selection after an impoundment. We assemble six food web models to search for the hypothesis that best predict observed prey selection pattern of piscivorous fishes combining the following assumptions: (i) predation window, defined as the size range of prey species consumed by a piscivorous fish; (ii) prey strategies to avoid predation (iii) and prey abundance. We tested the probability of each hypothesis to reproduce two empirical data, one before and one after an impoundment with minimum assumptions. Before impoundment, we found that predators presented switching behavior, preying preferably on abundant prey; while after impoundment, predators consumed prey within its predation window. Those results explained better than the null hypotesis and all other assumptions; and corroborate with both theoretical and empirical studies. We conclude that different assumptions drives piscivorous fish behavior in different environments; and modelling procedures can be used to assess gaps in trophic interactions of fish communities.

Alternative Stable States in Shallow Lakes

Chapter

Jan 2012

Consumptive and non-consumptive effects of predation by introduced northern pike on life-history traits in threespine stickleback

Article

Full-text available

May 2016
EVOL ECOL RES

Background: Non-native, predatory northern pike (Esox lucius) are spreading into lakes of south-central Alaska and were illegally introduced into Scout Lake in 2001 or 2002. Pike preyed on native threespine stickleback (Gasterosteus aculeatus) in the lake, subjecting them to higher mortality rates. Hypotheses: Life-history theory predicts evolutionary changes in threespine stickleback females arising from consumption by predators, including reduced body size, earlier age of reproduction, increased reproductive effort (greater clutch mass and clutch size), and, under some conditions, smaller offspring. Alternatively, energetically costly, non-consumptive predation-risk effects resembling food limitation - such as predator avoidance, reduced foraging efficiency, and chronic stress - might cause phenotypically plastic responses inconsistent with life-history theory. Methods: We measured changes in length, body mass, clutch mass, clutch size, and egg mass during an 11-year (1999-2009) study. In analyses of clutch mass, clutch size, and egg mass, we used body mass to correct for female size. Results: Consistent with predictions from life-history theory, the mean size and age of reproducing females declined, with one decline in size following the initial pike introduction and another after sport-fish stocking of salmonids was discontinued. The principal age at reproduction gradually shifted from two years to one year of age, with few females surviving to reproduce in a second year. Clutch mass and clutch size declined, suggesting non-consumptive predation-risk effects resembling those of nutrient deprivation. Egg mass showed an overall decline, with a moderate, temporary increase near the end of the study period.

A primer on potential impacts, management priorities, and future directions for Elodea spp. in high latitude systems: learning from the Alaskan experience

Article

Full-text available

Sep 2016
HYDROBIOLOGIA

Invasive species introductions in Arctic and Subarctic ecosystems are growing as climate change manifests and human activity increases in high latitudes. The aquatic plants of the genus Elodea are potential invaders to Arctic and Subarctic ecosystems circumpolar and at least one species is already established in Alaska, USA. To illustrate the problems of preventing, eradicating, containing, and mitigating aquatic, invasive plants in Arctic and Subarctic ecosystems, we review the invasion dynamics of Elodea and provide recommendations for research and management efforts in Alaska. Foremost, we conclude the remoteness of Arctic and Subarctic systems such as Alaska is no longer a protective attribute against invasions, as transportation pathways now reach throughout these regions. Rather, high costs of operating in remote Arctic and Subarctic systems hinders detection of infestations and limits eradication or mitigation, emphasizing management priorities of prevention and containment of aquatic plant invaders in Alaska and other Arctic and Subarctic systems.

Spring diet and trophic relationships between piscivorous fishes in Kaniv Reservoir (Ukraine)

Article

Full-text available

Feb 2016
FOLIA ZOOL

Abstract. Four piscivorous fishes such as pike, Esox lucius, European catfish, Silurus glanis, pikeperch, Sander lucioperca, and Eurasian perch, Perca fluviatilis, co-occur in Kaniv Reservoir (Ukraine). In total, 47 food items were identified in their diets including remains of fish and invertebrates. Sixteen prey items were identified in pike diet including 15 fish species; 33 prey items in European catfish diet, among which 20 fish species; 21 prey items in pikeperch diet, among which 18 fish species; and 28 prey items in perch diet, among which 12 fish species. The most important prey for pike were roach, Rutilus rutilus (%IRI = 25.9 %), Prussian carp, Carassius gibelio (34.7 %), and perch (18.4 %); for catfish – roach (55.5 %) and perch (20.6 %); for pikeperch – roach (52.8 %) and perch (34.1 %); and for perch – monkey goby, Neogobius fluviatilis (85.7 %). Highest diet overlap indices were observed between catfish and pikeperch (84.8 %) while the lowest between catfish and perch (33.7 %). No significant difference was observed between the average sizes of fish prey in the stomachs of pikeperch and European catfish (t-test, P > 0.05), but there were significant differences between all other pairs of piscivorous species (t-test, P < 0.001).

A review of Ruffe (Gymnocephalus cernua) life history in its native versus non-native range

Article

Full-text available

Jun 2016
REV FISH BIOL FISHER

Invasive Ruffe (Gymnocephalus cernua) has caused substantial ecological damage in North America, parts of Western Europe, Scandinavian countries, and the United Kingdom. The objectives of this review are to define Ruffe’s native and non-native range, examine life history requirements, explore the life cycle, and differentiate between life stages. We compare data from its native and non-native ranges to determine if there are any differences in habitat, size, age, genotype, or seasonal migration. Literature from both the native and non-native ranges of Ruffe, with some rare, translated literature, is used. In each life stage, Ruffe exhibit plasticity with regard to chemical, physical, biological, and habitat requirements. Adult Ruffe has characteristics that allow them to adapt to a range of environments, including rapid maturation, relatively long life and large size (allowing them to reproduce many times in large batches), batch spawning, genotype and phenotype (having plasticity in their genetic expression), tolerance to a wide range of water quality, broad diet, and multiple dispersal periods. There is, however, variability among these characteristics between the native, non-native North American, and European non-native populations, which presents a challenge to managing populations based on life history characteristics. Monitoring and preventative strategies are important because, based on Ruffe’s variable life history strategies and its recent range expansion, all of the Laurentian Great Lakes and many other water bodies in the UK, Europe, and Norway are vulnerable to Ruffe establishment.

Behavioral Change Due to Climate Change Effects Accelerate Tiger Human Conflicts: A Study on Sundarbans Mangrove Forests, Bangladesh

Article

Full-text available

Dec 2015

The change in climate has been observed over comparable periods of time. Mangrove ecosystem and its biodiversity are threatened due to climate change. Sundarbans mangrove ecoregion situated in Bangladesh (~62%) and India (~38%) is a bioclimatic zone. Sundarbans is one of the largest reserves for the Bengal tiger (Panthera tigris tigris L) which is the top predator. Therefore, it helps to regulate the number and distribution of prey, which in turn impacts forest structure, composition and regeneration. As climate change affects the flora and fauna in this ecosystem, these may be impaired because of migration of the species. The tigers become stray from forests to human inhabitants and causes tiger-human conflicts which often results in retaliatory killings of tiger and human and or livestock. Therefore, the main objective of this study is to identify the effects of climate change towards the salinity intrusion and biodiversity, modification of floral and faunal composition, habitat loss and behavioral change of wildlife, which ultimately identify the factors for accelerating tiger human conflicts. It reviewed related literature through various websites and the secondary data were quoted with necessary modification. The primary data obtained from the office records of Bangladesh Forest Department and a social surveying was conducted on livelihood profile of the people living surrounding the Sundarbans to identify the relations between tiger attacking and their livelihood and living style. We used ArcGIS 9.3 to visualize the tiger habitat and trigger up the causes of root of conflicts between human and tiger. The results reveal the climate change effects in the Sundarbans Mangrove forest through changing its biodiversity composition in terms of loss of wildlife habitats which is responsible for accelerating tiger human conflicts. It suggests, a social and cultural revolution for the sustainable alternative livelihood of forest-dependent population i.e., Alternative Income Generation (AIG), modification of the formal legal system, institutional development and in-depth research can minimize these issues towards the sustainability of Sundarbans mangrove forest.

Predation on the Invasive Copepod, Pseudodiaptomus forbesi, and Native Zooplankton in the Lower Columbia River: An Experimental Approach to Quantify Differences in Prey-Specific Feeding Rates

Article

Full-text available

Nov 2015
PLOS ONE

Invasive planktonic crustaceans have become a prominent feature of aquatic communities worldwide, yet their effects on food webs are not well known. The Asian calanoid copepod, Pseudodiaptomus forbesi, introduced to the Columbia River Estuary approximately 15 years ago, now dominates the late-summer zooplankton community, but its use by native aquatic predators is unknown. We investigated whether three species of planktivorous fishes (chinook salmon, three-spined stickleback, and northern pikeminnow) and one species of mysid exhibited higher feeding rates on native copepods and cladocerans relative to P. forbesi by conducting `single-prey' feeding experiments and, additionally, examined selectivity for prey types with `two-prey' feeding experiments. In single-prey experiments individual predator species showed no difference in feeding rates on native cyclopoid copepods (Cyclopidae spp.) relative to invasive P. forbesi, though wild-collected predators exhibited higher feeding rates on cyclopoids when considered in aggregate. In two-prey experiments, chinook salmon and northern pikeminnow both strongly selected native cladocerans (Daphnia retrocurva) over P. forbesi, and moreover, northern pikeminnow selected native Cyclopidae spp. over P. forbesi. On the other hand, in two-prey experiments, chinook salmon, three-spined stickleback and mysids were non- selective with respect to feeding on native cyclopoid copepods versus P. forbesi. Our results indicate that all four native predators in the Columbia River Estuary can consume the invasive copepod, P. forbesi, but that some predators select for native zooplankton over P. forbesi, most likely due to one (or both) of two possible underlying casual mechanisms: 1) differential taxon-specific prey motility and escape responses (calanoids > cyclopoids > daphnids) or 2) the invasive status of the zooplankton prey resulting in naivety, and thus lower feeding rates, of native predators feeding on invasive prey.

Trophic flexibility and opportunism in pike Esox lucius

Article

Full-text available

Sep 2015
J FISH BIOL

The first comprehensive investigation of pike Esox lucius trophic ecology in a region (Ireland) where they have long been thought to be a non-native species is presented. Diet was investigated across habitat types (lake, river and canal) through the combined methods of stable-isotope and stomach content analyses. Variations in niche size, specialization and the timing of the ontogenetic dietary switch were examined, revealing pronounced opportunism and feeding plasticity in E. lucius, along with a high occurrence of invertivory (up to 60 cm fork length, LF ) and a concomitant delayed switch to piscivory. Furthermore, E. lucius were found to primarily prey upon the highly available non-native roach Rutilus rutilus, which may alleviate predation pressure on brown trout Salmo trutta, highlighting the complexity of dynamic systems and the essential role of research in informing effective management.

Migration, growth patterns, and diet of pike (Esox lucius) in a river reservoir and its inflowing river

Article

Aug 2015
FISH RES

Einfluss von Seemorphologie, Habitatstruktur und Versauerung auf die Fischgemeinschaft in einem großen mesotrophen Braunkohletagebausee

Thesis

Jun 2011

Olaf Prawitt

Durch die Flutung stillgelegter Tagebaue entstehen zahlreiche Seen in den ostdeutschen Braunkohlerevieren. Sie sind überwiegend groß, oligo- bis mesotroph, und ihr Litoral ist nur in geringem Umfang durch Makrophyten strukturiert. Viele von ihnen sind versauert oder versauerungsgefährdet. In einer Feldstudie wurden (1) die Auswirkung von Seemorphologie und Habitatstruktur auf die Fischgemeinschaft des Senftenberger Sees, eines 1050 ha großen mesotrophen Tagebausees, und (2) die Säuretoleranz einheimischer Fischarten unter den hydrochemischen Bedingungen der geogen versauerten Tagebauseen untersucht. Die Fischgemeinschaft des Senftenberger Sees wurde von Barschen (Perca fluviatilis) und Plötzen (Rutilus rutilus) dominiert, wobei die verschiedenen Barsch- und Plötzengrößenklassen ihre Habitate durch Nutzung verschiedener Tiefenbereiche des Litorals segregierten. Innerhalb der flachen Litoralbereiche waren juvenile Plötzen und juvenile Güstern deutlich stärker auf die wenigen Makrophytenbestände fixiert als juvenile Barsche. Die Habitatwahl der Barsche zeigt, dass diese in mesotrophen Seen wahrscheinlich eher von den guten Sichtverhältnissen als von der strukturellen Komplexität submerser Makrophytenbestände profitieren. Als Ursache für die unterschiedliche Habitatwahl juveniler Barsche, Plötzen und Güstern wird postuliert, dass diese generell verschiedene Habitatwahlstrategien verfolgen. Während der entscheidende Parameter für die Habitatwahl juveniler Barsche die Optimierung der Energieaufnahme ist, folgen juvenile Plötzen und Güstern vorrangig einer Räubervermeidungsstrategie und sind daher sehr viel stärker auf strukturreiche Bereiche angewiesen. Die kritischen pH-Untergrenzen für die einzelnen Fischarten entsprachen weitgehend den publizierten Ergebnissen aus regenversauerten Weichwasserseen. Vermutlich wurde in den Tagebauseen der Säurestress, den die erhöhte Al-Konzentration von bis zu 0,6 mg/L verursachte, durch die ebenfalls erhöhte Ca-Konzentration kompensiert.

Food, Fear and Defence - Behavioral and morphological adaptation of juvenile perch under the risk of predation

Article

Jan 2011

Martina Heynen

Pokarm szczupaka z Zatoki Puckiej

Chapter

Full-text available

May 2023

Biodiversität, Angeln und Gesellschaft - Wissensbasierte Empfehlungen für ein nachhaltiges Fischereimanagement an Baggerseen

Book

Full-text available

Jun 2023

Seasonal and diurnal patterns of littoral microhabitat use by fish in gravel pit lakes, with special reference to supplemented deadwood brush piles

Article

Full-text available

Feb 2023
HYDROBIOLOGIA

The habitat quality of the littoral zone is of key importance for almost all lentic fish species. In anthropogenically created gravel pit lakes, the littoral zone is often structurally homogenized with limited fish habitats. We supplemented deadwood brush piles in the littoral zone of eight gravel pit lakes and investigated the diurnal and seasonal use of this and other typical microhabitats by six dominant fish species. Shoreline habitats were sampled using point abundance electrofishing during day and night in all four seasons, and patterns of fish abundance were compared amongst unstructured littoral habitats, emerged macrophytes and brush piles. We caught a total of 14,458 specimens from 15 species in the gravel pit lakes. Complex shoreline structures were used by all fish species that we examined, especially during daytime, whilst the use of unstructured habitats was highest during night. The newly added brush piles constituted suitable microhabitats for selected fish species, perch (Perca fluviatilis), roach (Rutilus rutilus) and pike (Esox lucius), particularly during winter. Supplemented deadwood provides suitable fish habitat in gravel pit lakes and may to some degree compensate for the loss of submerged macrophytes in winter by offering refuge and foraging habitat for selected fish species.

Gymnocephalus cernuus (ruffe)

Article

Jan 2022

Jeffrey Gunderson

This datasheet on Gymnocephalus cernuus covers Identity, Overview, Distribution, Dispersal, Diagnosis, Biology & Ecology, Environmental Requirements, Natural Enemies, Impacts, Uses, Prevention/Control, Further Information.

Habitat-dependent interactions between two size-classes of juvenile steelhead in a small stream

Article

Jan 1997
CAN J FISH AQUAT SCI

The presence of small steelhead (Oncorhynchus mykiss; averaging 55 mm fork length) influenced the growth of larger juvenile steelhead (90 mm fork length) during a 6-week experiment conducted in North Fork Caspar Creek, California, in summer 1994. In fenced replicate deep stream sections in this small stream, growth of the larger steelhead was greater in treatments in which small steelhead constituted half of the total biomass of fish than in treatments with an equal biomass comprised entirely of larger fish. In shallow habitats, growth of larger fish was lower in the presence of small fish. The growth of small fish was unaffected by the presence of larger juveniles and also was independent of habitat. Survival of both size-classes was high (70-90%) and unrelated to habitat or the presence of the other size-class. The advantage of large body size in intraspecific interactions among steelhead does not exist in all types of habitat, and interactions between the two size-classes may contribute to lower abundance of large juveniles in streams where aggradation reduces water depth.

Effect of Rearing Experience on the Survival, Growth, and Behavior of Hatchery‐Reared Largemouth Bass

Article

Apr 2018

Largemouth Bass Micropterus salmoides are commonly stocked throughout their native range, but survival of stocked fish is variable and often low. Hatchery fish may have difficulty switching to natural forage and providing feeding experience with natural prey in the rearing environment could result in improved growth and survival of Largemouth Bass after stocking. We conducted pond experiments to evaluate differences in growth and survival of Largemouth Bass reared in raceways and fed pellets or in ponds with either Bluegill Lepomis macrochirus prey or Fathead Minnow Pimephales promelas prey. Largemouth Bass reared on one of these three diets were stocked into ponds containing Bluegill prey. After two months, pellet‐reared Largemouth Bass were significantly smaller than either Fathead Minnow or Bluegill‐reared fish, whereas Fathead Minnow and Bluegill‐reared fish were similar. Fathead Minnow‐reared Largemouth Bass had lower survival than Bluegill‐reared fish, but no other survival differences were observed. To determine possible mechanisms influencing differential growth and survival of juvenile Largemouth Bass, we also conducted laboratory experiments examining the influence of prior feeding experience (pellets, Bluegill, or Red Shiner Cyprinella lutrensis) on foraging behavior and prey capture success in pools. Largemouth Bass reared on live forage captured prey faster, ingested more prey, and had higher capture efficiencies compared to fish reared on pellets. Combined, pond and laboratory experiments show prior acclimation to live prey may ultimately be beneficial to increasing growth of stocked hatchery Largemouth Bass and could result in increased recruitment. We recommend additional exploration of acclimation of Largemouth Bass fingerlings to natural prey, preferably Bluegill, prior to stocking to determine if hatchery managers should consider alternative rearing techniques. This article is protected by copyright. All rights reserved.

Ontogenetic microhabitat shifts of 0+ rudd ( Scardinius erythrophthalamus L.) in the littoral zone of a mesotrophic lake

Article

Jan 1998

Supplementary Material

Data

Full-text available

Aug 2017

References

Chapter

Apr 2008

J. F. Craig

Impact of the historical introduction of exotic fishes on the chironomid community of Lake Azul (Azores Islands)

Article

Jan 2017
PALAEOGEOGR PALAEOCL

Little is known about the effect of top predator introduction in historically fishless communities, especially on remote islands. This issue is important because it might strongly affect climate reconstructions derived from biota assemblages such as chironomids. Head capsule larval remains of chironomids have been studied in a 660 years lacustrine sedimentary sequence from Lake Azul (Sao Miguel Island, Azores archipelago) to assess the extent and timescale of the effect of the predator introduction occurring in this historically fishless lake. Analysis of similarity showed that the chironomid assemblage was statistically different before and after predator introduction (R = 0.78; p < 0.001). Abundance of chironomids was about 40% greater in the fishless lake period compared to the period in the presence of predator. Results show major change in chironomid assemblage coinciding with the first time of goldfish introduction (around 1790 CE), followed by carp (1890 CE) and pike (1979 CE) introductions. The composition of feeding group guilds changed following a pattern characterized by a decrease in abundance of detritivorous and predaceous taxa and an increase in abundance of grazing chironomid taxa. This study suggests that predator introduction was the most important factor affecting the chironomid assemblages in this natural, Azorean fishless lake, but predators did not affect all chironomid species. Other external forcings like major climate oscillations, anthropogenic activities in the catchment basin, and volcanic eruptions seem to play an additional role. The latest stage of the warm and arid Medieval Climate Anomaly (1000–1300 CE) favoured the occurrence of some warm-adapted chironomid taxa, which were absent through the Little Ice Age (ca. 1450–1850 CE) cool period.

Fisheries Management and the Interactive Dynamics of Walleye and Perch Populations

Chapter

Full-text available

Jan 1992

A major goal of fisheries management is to predict effects of management strategies on future population sizes. Natural populations are inherently variable through time. Analytical one-population models have revealed an impressive array of population behavior ranging from equilibrium to chaos (Ricker 1954; May and Oster 1976; Levin and Goodyear 1980), but these models are difficult to apply to the real world and it is unclear whether more complex biological systems behave similarly (Bledsoe and Megrey, in press). Empirical models are based on the observed relationships among variables and do allow description of average conditions from biological data. But these models often explain only a small portion of the variability in the data (see Walters 1986). This poor explanatory power is often assumed to be the result of invironmental variability. It is therefore not suprising that application of empirical models to new situation has been largely unsuccessfull (Sissenwine 1984; Getz and Haight 1989).

Fish-Habitat Interactions Mediated via Ontogenetic Niche Shifts

Chapter

Jan 1998

A fundamental characteristic of fish is that individuals increase in size by several orders of magnitude over their ontogeny (Werner, 1988). This increase in size generally means that the individual changes its food resource use during development. The change in resource use can take many different routes involving changes between carnivory and herbivory/detritivory (Gerking, 1994). Commonly, an increase in prey size eaten is observed in connection with the increase in consumer size, which potentially involves a change from zooplanktivory, to ben-thivory, and ultimately, to piscivory (Persson, 1988; Osenberg et al., 1994; Olson et al., 1995). These changes in resource use are, in turn, generally associated with habitat shifts in which complex habitats such as vegetated areas of lakes may function both as a resource base and as a refuge from prédation (Heck and Crowder, 1991; Mittelbach and Osenberg, 1993;Persson, 1993; Olson et al., 1995; Persson and Eklöv, 1995).

Fish spatial distribution in the littoral zone of Lake Pareloup (France) during summer

Article

Dec 2001
Arch Hydrobiol

We studied the spatial distribution of 11 fish species in the littoral zone of Lake Pareloup (South-West of France) using a non-destructive Point Abundance Sampling by Scuba diving. The fish spatial assemblage was investigated with seven commonly used environmental variables (topographical, biological and substratum variables). Three fish groups colonising three different habitats were identified. The spatial distribution of each fish species was mainly influenced by two environmental factors: distance from the bank (highly correlated with depth) and vegetation cover, i) Young-of-the-year (YOY) cyprinids and northern pike were mainly associated with a small distance from the bank (less than 6m). ii) Older cyprinids and perch (≥1+) were located between 6 and 12 m from the bank. iii) YOY perch and older northern pike (≥1+), occurred independently of the distance from the bank, but exhibited different responses to the percentage of vegetation cover: pike preferred areas with dense Vegetation cover, while YOY perch abundance decreased rapidly with increasing vegetation cover. Thus, YOY fishes were common and abundant in shallow water, whereas large predators such as northern pike were found in vegetated areas. Therefore, vegetation cover, although generally considered as a crucial 0+ fish habitat, was here a secondary variable after distance from the bank. We hypothesised that the high density of predators (and especially northern pike) inside the vegetation as well as their high predation efficiency in this area could explain such a spatial distribution, shallow littoral areas being, in that case, safer from predation than vegetated ones for YOY fishes.

Grazing Minnows, Piscivorous Bass, and Stream Algae: Dynamics of a Strong Interaction Author(s)

Article

Full-text available

Oct 1985

Striking differences in pool-to-pool distributions of an algae-grazing minnow (Campostoma anomalum), attached algae (predominantly Spirogyra sp and Rhizoclonium sp), and bass (Micropterus salmoides, M. punctulatus) occur in some small Oklahoma streams. Bass and minnow distributions in 14 consecutive pools were inversely related in 6 or 7 censuses. Minnow and algal abundances were inversely related during late summer and autumn. This relationship did not hold during spring, when floods strongly affected algal distributions. During autumn the authors removed bass from a pool, fenced it longitudinally, and added Campostoma to one side (1.4 individuals/m2). Over the next 5wk, standing crop of algae decreased significantly on the Campostoma side but increased on the control side. In a nearby unmanipulated Campostoma pool, standing crop of algae was consistently low.-from Authors

Habitat Selection Under Predation Hazard: Test of a Model with Foraging Minnows

Article

Full-text available

Dec 1987

Animals commonly choose among habitats that differ both in foraging return and mortality hazard. However, no experimental study has attempted to predict the level of increase in resources, or the decrease in mortality hazard, which will induce a forager to shift from a safer to a more hazardous (but richer) foraging area. Here we present and test a model that specifies the choice of foraging areas ("habitats") that would minimize total mortality risk while allowing collection of some arbitrary net energy gain. We tested the model with juvenile creek chubs (Semotilus atromaculatus) in an experimental field stream in which the foragers could utilize a foodless refuge and choose between two foraging areas that differed in experimentally manipulated resource densities (Tubifex spp. worms in sediments) and mortality hazard (adult creek chubs). For the case tested, the model specified a simple rule: "use the refuge plus the site with the lowest ratio of mortality rate (μ) to gross foraging rat (f)," i.e., "minimize μ./f." Independent prior measurements of mortality hazard (as a function of predator density) and gross foraging rate (as a function of resource density) allowed us to predict the resource level in the more hazardous foraging site that should induce a shift from the safer to the more hazardous site. The chubs' preferences in subsequent choice experiments agreed well with the theoretical predictions. The "minimize μ/f" rule (deaths per unit energy), perhaps in modified form, provides a simple alternative to the "maximize f" (energy per unit time) criterion that applies to long-term rate maximization when predation hazard does not differ among choices.

An Experimental Test of the Effects of Predation Risk on Habitat Use in Fish

Article

Full-text available

Dec 1983

Identical populations of 3 size-classes of bluegill sunfish Lepomis macrochirus were stocked on both sides of a divided pond (29m in diameter), and 8 piscivorous largemouth bass Micropterus salmoides were introduced to one side. Only the small size-class suffered significant mortality from the bass (each bass consumed on average about one small bluegill every 3.8 d); the 2 larger size-classes exhibited similar mortality rates on both sides of the pond. In the absence of the bass, habitat use of all size-classes was similar and the pattern of habitat use maximized foraging return rates. In the presence of the bass the 2 larger size-classes chose habitats to maximize return rates, but the small size-class obtained a greater fraction of its diet from the vegetation habitat, where foraging return rates were only 1/3 of those in the more open habitats. The small size-class further exhibited a significant depression in individual growth in the presence of the bass; the growth increment during the experiment was 27% less than that for small bluegills in the absence of the bass. -from Authors

Food Consumption and Competition between Age Classes in a Perch Perca fluviatilis Population in a Shallow Eutrophic Lake

Article

Feb 1983

Lennart Persson

Food consumption was low, suggesting that the fish were highly resource limited. Food overlap was high. The age classes could not segregate on the habitat dimension to any large extent, because of the pronounced habitat homogeneity. When comparing perch populations in lakes differing in area, depth and transparency, the length class diversity was higher in more transparent lakes which offered a more diversified habitat for visually hunting predators such as perch. Intraspecific competition thus limits the diversity and number of age classes, all the more the lower the habitat heterogeneity. - from Author

The Role of Fish Predation and Spatial Heterogeneity in Determining Benthic Community Structure

Article

Apr 1984

Ellen Gilinsky

Bluegill sunfish Lepomis macrochirus predation had a significant impact on both the number of benthic species and the densities of certain benthic macroinvertebrate groups. The predatory chironomid Clinotanypus pinguis showed a strong negative response to bluegill predation, with fish exclusion resulting in higher densities throughout the year. A group of herbivorous chironomids exhibited a response to fish predation that varied over the year, with predation resulting in elevated densities in the fall and winter but reduced densities in the summer. Many of the other species found in the littoral zone showed no significant response to bluegill predation. In addition, fish predation had no significant effect on densities of most macroinvertebrates occurring on the macrophytes. These complex responses of the various macroinvertebrates to fish predation are explainable in terms of seasonal changes in predation intensity and the importance of invertebrates vs. vertebrate predation.-from Author

Some Observations of Food Selectivity by Northern Pike in Aquaria

Article

Jan 1968

Northern pike confined in tanks and aquaria were presented various species and sizes of food fishes. The optimum size of centrarchids eaten by 7- to 12-inch northern pike was 1.5 inches, and by 13- to 23-inch northern pike 2.5 inches. The northern pike selected minnows and chubsuckers over centrarchids and yellow perch. They showed no choice between centrarchids and yellow perch, but selected centrarchids over bullheads.These results increase doubt as to the effectiveness of northern pike for controlling pan fish populations in lakes, and suggest that large populations of appropriate size soft-rayed food fishes favor good growth of northern pike.

Predation and Risk in Foraging Minnows: Balancing Conflicting Demands

Article

Apr 1983

When foraging in habitat patches that simultaneously vary in food abundance and predation risk, foragers confront the conflicting demands of efficient foraging and predator avoidance. We hypothesized that foragers will balance these conflicting demands, taking proportionately greater risks when benefits are high. To test the balancing hypothesis we predicted that (1) prey would choose patches of high food abundances when all other variables are constant; (2) prey would avoid predator locations when all other variables are constant; and (3) when food and predators vary in combination, a significant statistical interaction would exist between the two effects. We used adult Semotilus atromaculatus as the predators and juvenile Rhinichthys atratulus as the prey, to test these predictions in a seminatural, artificial stream. When specific locations in the stream were varied in all possible combinations of food level (high, low) and predators (present, absent) we found that the prey responded positively to high...

The Role of Predation in Shaping and Maintaining the Structure of Communities

Article

May 1979

John Glasser

Ontogenetic Habitat Shifts in Bluegill: The Foraging Rate-Predation Risk Trade-off

Article

Oct 1988

After hatching in the littoral zone, bluegill sunfish Lepomis macrochirus fry migrate to the pelagic zone to feed on zooplankton. Fry returned to the littoral zone in 4 different Michigan lakes at a relatively constant size of c12.5 mm standard length. Several years are spent feeding in the littoral zone vegetation before the bluegill again shifts to feeding on zooplankton, first in the water column above littoral vegetation and subsequently in the true pelagic zone. This shift to feeding on zooplankton occurred at a specific body size within a lake, but the size ranged from 50-83 mm among 5 different lakes. Size at which the shift occurred was directly correlated with the density of the major predator of the bluegill in these lakes, largemouth bass Micropterus salmoides. The bluegill is faced with a growth (or feeding) rate-predation risk trade-off in making these habitat shifts. Analyses of stomach contents, growth of small fish caged in the pelagic zone, and predictions of foraging rates in both habitats all indicate that the pelagic zone is the more profitable for all size classes of bluegill. Risk of predation by largemouth bass was 40-80 times as great for small bluegills in open water as for those in vegetation. Bluegill can facultatively respond to changes in feeding rates and predation risk. -from Authors

Escape tactics used by bluegills and fathead minnows to avoid predation by tiger muskellunge

Article

Jan 1983

To explain why esocids prefer cylindrical, soft-rayed prey over compressed, spiny-rayed prey, we quantified behavioral interaction between tiger muskellunge (F1 hybrid of male northern pike Esox lucius and female muskellunge E. masguinongy) and fathead minnows (Pimephales promelas) and bluegills (Lepomis macrochirus). Tiger muskellunge required four times as many strikes and longer pursuits to capture bluegills than fathead minnows. Tiger muskellunge attacked each prey species differently; fathead minnows were grasped at midbody and bluegills were attacked in the caudal area. Each prey species exhibited different escape tactics. Fathead minnows remained in open water and consistently schooled; bluegills dispersed throughout the tank and sought cover by moving to corners and edges. Due to their antipredatory behavior (dispersing, cover seeking, and remaining motionless) and morphology (deep body and spines), bluegills were less susceptible to capture by tiger muskellunge than were fathead minnows.

Risk of predation and the feeding behaviour of juvenile Coho salmon (Oncorhynchus kisutch)

Article

Jan 1984

During their first 1–2 years of life, juvenile coho salmon (Oncorhynchus kisutch) are stream-dwelling, and feed upon drifting invertebrates. They move upstream from a holding position to intercept individual prey items; the distance moved (attack distance) is an increasing, but decelerating, function of prey size. Since the fish are presumably more visible to predators during such feeding excursions, prey size and risk are associated variables. The effect on attack distance of the presentation of a model predator (a photograph of a rainbow trout) was examined in the laboratory. Attack distances are shortened following presentation of a predator; this is particularly true when the prey are large (Fig. 1). The extent of the reduction of attack distance is directly related to predator presentation frequency, although there appears to be a minimum level to which it will decline (Fig. 2). Hungry fish and fish in the presence of a competitor (simulated by a mirror) are less responsive to the predator, suggesting a trade-off of energetic requirements and risk (Fig. 3 and Table 3). The effect of predation risk should be to reduce the relative proportion of large prey in a juvenile coho's diet, and its net rate of energy intake.

Experimental evidence for interactive habitat segregation between Roach (Rutilus rutilus) and Rudd (Scardinius erythrophthalmus) in a shallow eutrophic lake

Article

Aug 1987

L. Johansson

The competitive interactions between roach (Rutilus rutilus) and rudd (Scardinius erythrophthalmus) were investigated in two habitats, the open water and the waterlily zone. The growth rates of both species in enclosures were lower when confined together than when alone, demonstrating interspecific competition. Allopatric roach had the highest growth rate in both habitats although the open water was preferred. The diets of both species were dominated by zooplankton in both the open water and waterlily zones. In laboratory experiments, roach had significantly higher feeding rates than rudd when fed D. magna and Cyclops sp. The impact of roach on the mean sizes and densities of zooplankton in the enclosures, together with the results from the laboratory study, indicate that roach were competitively superior in the open water. Because of high mortality in the sympatric waterlily enclosure, no conclusions about interspecific competition in this habitat could be drawn. The observed habitat segregation between roach and rudd was at least partly interactive.

Predatory Efficiency and Prey Selection - Interactions between Pike Esox-Lucius, Lucius, Perch Perca-Fluviatilis and Rudd Scardinus-Erythrophthalmus

Abstract

No full-text available

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