Article

Habitat Partitioning in a Freshwater Fish Community

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Abstract

The patterns of habitat utilization in the littoral zone fish community of two small southern Michigan lakes were examined. Abundance and habitat use of the fish were quantified by underwatertransect censuses. The sunfishes (Centrarchidae) dominated the communities numerically and by weight, with two species, the bluegill (Lepomis macrochirus) and largemouth bass (Micropterus salmoides) accounting for 85% of the community biomass. Spatial (habitat) segregation of species was evident along gradients of depth (distance from shore), vertical height in the water column, and vegetational structure. Several species showed intraspecific differences in the spatial distribution of size-classes. Comparative analyses of habitat use in the two lakes suggest that small size-classes are confined by predation to areas of dense cover and that within these areas competition determines space utilization by different species. The patterns of habitat use are discussed in relation to the food habits and morphology of species in this community. Only one clear case of segregation of two species by food size occurs (bass and bluegill); most other species segregate predominantly by habitat. The rarer centrarchids show strong niche complementarity with the codominant bass and bluegill.

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... Les poissons trouvent également dans cette zone d'importantes ressources trophiques . Les abondances sont généralement plus grandes en zone littorale que dans les autres zones (Keast and Harker 1977;Werner, Hall et al. 1977). ...
... In lentic systems, it is well known that depth, vegetation cover and substrate size are important in the spatial 53 segregation of fish in the littoral zone (Werner et al., 1977;Rossier, 1995;Fischer & Eckmann, 1997b;Gasith et 54 al., 2000;Laffaille et al., 2001;Lewin et al., 2004;Brosse et al., 2007;Kratochvıl et al., 2012). From a 55 hydrological point of view, reservoirs are at the boundary between streams and lakes, with their own functioning, 56 which is highly dependent on human uses resulting in irregular and extreme variations in physical factors 57 . ...
... Because they are interfacing aquatic and terrestrial systems, littoral zones have a greater heterogeneity of 61 physical structure Zohary & Ostrovsky, 2011), and thus habitat, and greater trophic resources 62 than pelagic areas . The littoral zone is crucial for the development of numerous species that 63 use these habitats to accomplish their biological cycle (Werner et al., 1977;Keast, 1985;. ...
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Aquatic ecosystem functioning in human-impacted environments is highly dependent of its uses; in consequence, the environment of biological communities is generally fluctuating. Studying the link between environment and organism in fluctuating environments is generally more complex compared to steady environments. The main objective of this work was to better understand how fish populations respond to environmental modifications in a reservoir affected with water level fluctuations (WLF), the Bariousses’s reservoir located on the Vézère River. A multiscale approach was used with different biological (community and individual) and temporal (annual and daily cycles) scales. A special attention was given to the littoral zone as it plays a key role for lake fish communities and since it is strongly affected by WLF. This work is divided in 4 parts. The first part presents the characteristics of the study site and the second part describes the impact of WLF on the studied habitats using a mapping of the littoral zone. The consequences of hydrological stress through the changes in habitat conditions were also analyzed as well as the effects of water temperature and photoperiod. The third part shows the effect of the temporal variability of environmental conditions induced by WLF on the composition of the littoral fish community (sampled by electrofishing). The fourth part presents an innovative positioning system acoustic telemetry (Vemco Positioning System) that was used to study the impact of WLF at the individual scale by analyzing the behavior of 90 individuals from three different fish species (pikeperch, pike and perch) with a satisfactory accuracy (average error of 3.3 m after filtration). The results of this work showed that WLF induced a temporal variability of the littoral zone surface and volume. In addition, a gradual decrease of the structural complexity of littoral habitats was associated with lower water level inducing a trend to homogenization (dominance of thinner substrates without vegetation). Despite these changes in habitats conditions induced by WLF, littoral fish community did not show any clear change in composition. High inter-individual variability of behavioral responses was observed in response to environmental fluctuations, but the temperature and photoperiod were the two major structural parameters controlling fish activity and spatial distribution. Water level affected a part of the fish population since more individuals attended the littoral zone and were less mobile when available habitats were more complex (with a high water level). These results allowed us to suggest some ideas for the management of water levels in the studied reservoir focused on the fish population. Keywords: reservoir, fish, littoral zone, water level fluctuations, temperature, photoperiod, individuals.
... The among-species variability in the mean conditional detection probabilities (pjN) and habitat variables likely reflects the selection of habitat types in areas where species are better adapted (Werner et al. 1977;Savino and Stein 1982). Several models and theories of habitat use suggest habitat tends to be used to maximize profitability, which is a tradeoff between foraging efficiency and predator avoidance (Savino and Stein 1982). ...
... Developed reservoirs are commonly associated with reduced diversity and availability of habitat types for fish (Christensen et al. 1996;Jennings et al. 1996); thus the homogenization of habitat structures (e.g., fishing piers and rip-rap) might not benefit all species and explain the negative relationships observed in this study. Conversely, the abundance of sunfishes was positively associated with the percentage of agriculture, likely a result of increased nutrient productivity that increases zooplankton prey biomass (Werner et al. 1977;Savino and Stein 1982). Though we did not examine zooplankton abundance, we think this is a likely explanation because of the similar trend observed between abundance of most sunfish species and chlorophyll a (Hinch and Collins 1993). ...
Article
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Species distribution models are useful tools to evaluate habitat relationships of fishes. We used hierarchical Bayesian multispecies mixture models to evaluate the relationships of both detection and abundance with habitat of reservoir fishes caught using tandem hoop nets. A total of 7,212 fish from 12 species were captured, and the majority of the catch was composed of Channel Catfish Ictalurus punctatus (46%), Bluegill Lepomis macrochirus (25%), and White Crappie Pomoxis annularis (14%). Detection estimates ranged from 8% to 69%, and modeling results suggested that fishes were primarily influenced by reservoir size and context, water clarity and temperature, and land-use types. Species were differentially abundant within and among habitat types, and some fishes were found to be more abundant in turbid, less impacted (e.g., by urbanization and agriculture) reservoirs with longer shoreline lengths; whereas, other species were found more often in clear, nutrient-rich impoundments that had generally shorter shoreline length and were surrounded by a higher percentage of agricultural land. Our results demonstrated that habitat and reservoir characteristics may differentially benefit species and assemblage structure. This study provides a useful framework for evaluating capture efficiency for not only hoop nets but other gear types used to sample fishes in reservoirs.Received October 14, 2014; accepted December 23, 2015
... Insbesondere junge Fische nutzen im Sommer die warmen, hochproduktiven, flachen Uferzonen des Litorals, um ihre Wachstumsrate zu steigern (Werner et al. 1983). Daher sind die vegetationsreichen Ufer eines Sees wesentliche Jungfischlebensräume (Bryan & Scarneccia 1992, Lewin et al. 2004 (Werner et al. 1977, Keast 1985, weil Habitat-und Nahrungsressourcen in litoralen Gewässerbereichen diverser und reichhaltiger sind (Werner et al. 1983, Pierce et al. 1994. Im Allgemeinen ist die Fischartengemeinschaft in Habitaten hoher Strukturheterogenität diverser und artenreicher (Keast et al. 1978, Eadie & Keast 1984, Benson & Magnuson 1992, Eklöv 1997, Jennings et al. 1999, Pratt & Smokorowski 2003. ...
... Anstelle der erwarteten positiven Korrelationen mit den morphologischen Gewässervariablen der Größe und Tiefe, zeigten sich in der vorliegenden Studie für die Diversität und die Artenzahl zum Teil signifikante und durchgehend negative Korrelationen. In bisherigen Studien, in welchen dieser Zusammenhang untersucht wurde (Minns 1989, Eckmann 1995 (Werner et al. 1983, Pierce et al. 1994) steigen sollte, wurde für natürliche Gewässer von Keast (1985), Werner et al. (1977) und Benson & Magnuson (1992) bestätigt. Produktivität (Hanson & Leggett 1982, Downing et al. 1990 Barschen zu Cypriniden mit steigendem Trophiegrad postuliert wurde (Persson et al. 1991, Jeppesen et al. 2000, Olin et al. 2002 (Keast et al. 1978, Eadie & Keast 1984, Benson & Magnuson 1992, Eckmann 1995, Eklöv 1997, Jennings et al. 1999, Pratt & Smokorowski 2003. ...
Article
Die Rolle biotischer und abiotischer Faktoren für die Zusammensetzung von Fischartengemeinschaften in Stillgewässern wurde bereits vielfach untersucht. Bisherige vergleichbare Analysen fokussierten jedoch zumeist auf große (> 50 ha) natürliche Gewässersysteme oder auf ausgewählte Habitate. Kleine, künstlich geschaffene Standgewässer, vor allem Abgrabungsgewässer, waren hingegen selten Gegenstand fischfaunistischer wissenschaftlicher Untersuchungen. In vorliegender Studie wurden die litoralen Fischbestände von 19 angelfischereilich bewirtschafteten, kleinen (0,69 bis 11,93 ha) und flachen (maximale Tiefe 1,1 bis 12,8 m) Baggerseen in Niedersachsen untersucht. Fischfaunistische Kennwerte wurden in den Jahren 2011 und 2012 mithilfe von Stellnetzen und Elektrofischerei quantifiziert. Die ermittelten Fischgemeinschaftskennzahlen wurden sodann auf lineare Zusammenhänge mit morphologischen und produktionsbiologischen Umweltvariablen und Charakteristika der Habitatstruktur getestet, um die strukturierenden Faktoren der Fischartengemeinschaft zu ermitteln. Die 19 Untersuchungsgewässer waren insgesamt artenreich (bis zu 19 Fischarten pro Gewässer, im Mittel 12 ± 3 Arten). Hecht (Esox lucius) und Karpfen (Cyprinus carpio) waren in allen Gewässern vertreten, Aal (Anguilla anguilla), Barsch (Perca fluviatilis), Plötze (Rutilus rutilus), Rotfeder (Scardinius erythrophthalmus) und Schleie (Tinca tinca) in 95% der Baggerseen. Standortuntypische, rheophile Arten wurden höchst selten angetroffen, ebenso nichtheimische Arten, was auf eine naturschutzfachlich nachhaltige Bewirtschaftung durch die Angelvereine hinweist. Biomasse und Abundanz der Fische im Litoral, vor allem der Barsche und Plötzen, korrelierten überwiegend positiv mit Anzeigern des Trophiestatus und der Gewässerproduktivität (Chlorophyll a, Gesamtphosphor und Sichttiefe), während Raubfischabundanzanteile zurückgingen. Zudem nahm den Erwartungen entsprechend mit steigendem Trophiegrad die mittlere Totallänge des Durchschnittsfisches in der Gemeinschaft ab. Auch die mittlere Gewässertiefe stellte sich als relevanter Strukturfaktor der Fischartengemeinschaft heraus: Mit zunehmender mittleren Tiefe verringerten sich Abundanz und Biomasse von Fischen im Litoral sowie die Artenzahl der Gemeinschaft. Der Effekt der von Makrophyten geprägten Habitatstruktur wurde durch die produktionsbiologischen und morphologischen Faktoren überlagert. Die vorgelegte Studie belegt, dass vor allem der Nährstoffgehalt und die Gewässermorphologie die Fischgemeinschaft von Baggerseen bestimmen, ähnlich wie zuvor für natürliche Standgewässer in Norddeutschland beschrieben. Geringe Wassertiefen und hohe Nährstoffgehalte in Form von Phosphor, indiziert durch vergleichsweise trübes Wasser, erhöhen der Studie zufolge die Tragekapazität der Gewässer für Fischbiomasse. Die Anlegung von Flachwasserbereichen in tiefen Baggerseen ist eine empfehlenswerte Managementmaßnahme, um die Fischbestände zu steigern.
... Centrarchids are prevalent throughout the southeastern United States (Douglas 1974;Desselle et al. 1978;Ross 2001), where they often dominate the abundance and biomass of littoral fish assemblages (e.g., Werner et al. 1978;Bachmann et al. 1996;Winemiller et al. 2000). Depending on competitive interactions, trophic functional morphology (Wainwright 1996), and resource availability (Werner et al. 1977;Mittelbach 1984;Bootsma et al. 1996), sympatric centrarchids can exhibit strong partitioning of prey resources (George and Hadley 1979;Laughlin and Werner 1980). Several centrarchid species have been the subject of trophic partitioning studies, including the Largemouth Bass Micropterus salmoides and Alabama Bass Micropterus henshalli (Wheeler and Allen 2003); the Rock Bass Ambloplites rupestris and Bluegill Lepomis macrochirus (Paterson et al. 2006); and the Bluegill, Pumpkinseed Lepomis gibbosus, and Green Sunfish Lepomis cyanellus Hall 1976, 1979;Werner et al. 1977). ...
... Depending on competitive interactions, trophic functional morphology (Wainwright 1996), and resource availability (Werner et al. 1977;Mittelbach 1984;Bootsma et al. 1996), sympatric centrarchids can exhibit strong partitioning of prey resources (George and Hadley 1979;Laughlin and Werner 1980). Several centrarchid species have been the subject of trophic partitioning studies, including the Largemouth Bass Micropterus salmoides and Alabama Bass Micropterus henshalli (Wheeler and Allen 2003); the Rock Bass Ambloplites rupestris and Bluegill Lepomis macrochirus (Paterson et al. 2006); and the Bluegill, Pumpkinseed Lepomis gibbosus, and Green Sunfish Lepomis cyanellus Hall 1976, 1979;Werner et al. 1977). The role of functional morphology in understanding and predicting trophic ecology has been examined (e.g., Lauder 1983;Wainwright and Richard 1995;Wainwright 1996), but no studies have examined the trophic relationships of more diverse assemblages of co-occurring centrarchids. ...
Article
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We examined trophic and habitat resource partitioning among seven centrarchid species inhabiting four macrohabitat types in the Atchafalaya River basin (ARB), a 900-km2 bottomland hardwood swamp in south-central Louisiana. Fish (n = 2,036) were collected at 24 sites by boat electrofishing, and trophic position was determined from stomach contents and tissue analysis of 15N and 13C stable isotope signatures (n = 140). Stomach content analysis (index of relative importance), Morisita's index of dietary overlap, and canonical correspondence analysis revealed little effect of ARB macrohabitat type on centrarchid trophic relationships despite significant habitat alterations in dredged canals. Analyses revealed substantial diet overlap among three predominately insectivorous species (Bluegill Lepomis macrochirus, Redspotted Sunfish L. miniatus, and Longear Sunfish L. megalotis), whereas much more distinctive trophic positions were occupied by Largemouth Bass Micropterus salmoides (dominant prey = fish), Black Crappies Pomoxis nigromaculatus (palaemonid shrimp), Redear Sunfish L. microlophus (mollusks), and Warmouths L. gulosus (crayfish). Stable isotope signatures reflected dietary differences among species and complemented stomach content analyses in assessing the feeding ecology of these centrarchids, although isotopic similarities were sometimes higher than actual similarities in diet composition. Results suggest that centrarchid functional morphology and prey selection, combined with the diversity and productivity of ARB littoral habitats, effectively reduce the potential for competition among the seven cohabiting centrarchids.Received October 28, 2014; accepted March 31, 2015
... In large rivers, hydraulic conditions are more uniform, and other factors can be involved in patterns of fish habitat use. Among these factors, aquatic vegetation contributes to an increase in habitat structural complexity (Hutchinson, 1975; Chambers, 1987; Chambers & Kalff, 1987; Sand-Jensen & Mebus, 1996), and thus is an important determinant of fish habitat selection (Werner et al., 1977; Crowder & Cooper, 1982; Killgore et al., 1989; Chick & McIvor, 1994). ...
... Habitat shifts with respect to prey size have been observed both in experimental and field studies (Mittelbach, 1981) and have been discussed in the light of optimal foraging theory. Some studies revealed species-specific dietary selection by juvenile fishes (Garner, 1996a), but other studies revealed large overlaps in the range of prey sizes eaten between fish size classes (Hall et al., 1970; Keast, 1977; Werner et al., 1977). Fish diet investigations should now be conducted to verify if observed habitat shifts, with respect to available prey size, also correspond to shifts in consumed prey. ...
Article
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Juvenile fish were sampled by electric fishing using the point abundance sampling method in September 1998 in the Lower Saone River, during a very low discharge period when current velocity was not the structuring factor. Patterns exhibited by the four most abundant species were investigated at different spatial scales of habitat heterogeneity using logistic regression analysis. At the higher scale (distinction between side-arms and channel), significant responses were always characterized by higher probabilities of presence in side-arms. Three of the four species showed patterns at the mesohabitat scale (the different macrophytes beds), At the microhabitat scale (the sampling point), the role of aquatic macrophytes was investigated by distinguishing the main species. In order to investigate the relationship between juvenile fish abundance and food habitat characteristics, phyto- and zooplankton were sampled in each mesohabitat, in both channel and side-arms. The type of vegetation appeared to be crucial in the determination of plankton abundance, but plankton abundance was not sufficient to explain patterns of habitat use in the fishes. Morphological characteristics of the different macrophytes studied were contrasted. Then we hypothesized that such differences resulted in different habitat quality (i.e. protection against predators) and may have affected the habitat use of juvenile fishes.
... On the contrary, the Arno River community showed some overlap among trophic niches of fish species, but not a clear segregation of all niches as observed in Arreo Lake (Haubrock et al., 2019a), as the latter was the result of the low species number and a common geographic origin. Estimations of trophic positions showed a strong top predator behavior for S. glanis, I. punctatus, especially in the juvenile stage, and also L. gibbosus, coherently with their known biology and other isotope studies (Werner et al., 1977;Syväranta et al., 2010). Compared with Haubrock et al. (2019a), L. gibbosus was identified as a possibly secondary -not a primary-predator. ...
... In the case of I. punctatus and L. gibbosus, as these two species co-occur in the same ecosystems in North America (Werner et al., 1977;Smith, 1981) and thus, share a common life-history and overlapping native range as well as history of co-evolution, some niche overlap was identified. Moreover, the applied PERMANOVA did not indicate a statistically significant difference between juvenile catfish and pumpkinseed trophic niches. ...
Article
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Interactions occurring between species in multiple invaded freshwater ecosystems are often difficult to observe and study. Studies on invasive alien species typically focus on single species, and, when the species community is exclusively composed of alien species, their interactions, eventual facilitation and hindering processes are very scarcely assessed. To investigate such a community, the species community in the Arno River (Tuscany, Italy) was examined as a model system using the combined approach of stable isotopes and dietary analyses. Established alien species have formed a pyramid shaped community with the European catfish Silurus glanis and the North American channel catfish Ictalurus punctatus in the apex position, followed by opportunistic predatory (Lepomis gibbosus) and omnivore (Alburnus alburnus, Cyprinus carpio, Barbus barbus, Pseudorasbora parva, Padogobius sp., Tinca tinca) species. These species were observed to feed on a variety of primary producers (Myriophyllum sp., Potamogeton sp., Phragmites australis) and consumers (aquatic insects, molluscs, Dikerogammarus villosus, Procambarus clarkii, Palaemon antennarius, tadpoles). Remarkably, the channel catfish Ictalurus punctatus showed an ontogenetic niche shift, with juveniles occupying a slightly higher trophic position than mature individuals. Pseudorasbora parva and A. alburnus showed a strong niche overlap, with the former having a wider niche. Such wide niches were also found for the invasive crustaceans D. villosus and P. clarkii. Outgoing from our findings, we suggest that life-history and geographic origin play a role in determining competition and interaction type among alien species, with species from the same geographic area showing a lower potential to compete than species from different areas, hence affecting their potential impact on native species.
... Consequently, variation in diet composition and diet diversity are usually high. Tricolored Herons are special- to high vegetation complexity that provide a mosaic of cover types, adequate protective cover to avoid larger predatory fish, and di- verse substrates for invertebrate prey (Werner et al. 1977, Chick 1992, Chick and Mclvor 1994. Sampling on Lake Okeechobee sug- gests that habitats dominated by introduced species of Hydrilla often harbor very high concentrations of small fishes, but similar native habitats that include mixes of Vallisne- ria, Potamogeton, Polygonum, and Panicum also provide excellent habitat for these fish spe- cies ( Bull et al. 1992, Mclvor and Smith 1992, Chick and Mclvor 1994 and may support more diverse assemblages of species and siz- es of fish. ...
Article
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Based on the composition of nestling regurgitations collected during 3 breeding seasons, fish were the most important prey group for Great Egrets (Ardea alba: N = 200 nest-day samples; aggregate percent biomass [APB] = 73.4%), Snowy Egrets (Egretta thula: N = 115; APB = 91.4%), and Tricolored Herons (E. tricolor: N = 68; APB = 97.3%). For Little Blue Herons (E. caerulea: N = 57), grass shrimp (Palaemonetes paludosus; APB = 39.7%) ranked higher in overall importance than all fishes combined (APB = 36.5%). Dietary overlap, as measured by Schoener's Similarity Index, was greatest between Snowy Egrets and Tricolored Herons (77%) and lowest between Tricolored Herons and Little Blue Herons (30%). Diet diversity, as measured by Shannon's Index, was highest for Great Egrets (2.04), intermediate for Snowy Egrets (1.71) and Tricolored Herons (1.68), and lowest for Little Blue Herons (1.60). Great Egrets ate a wider variety of fish species and sizes, especially larger fishes, and more crayfish than the other species. Little Blue Herons ate fewer fish and more grass shrimp and insects, and ate smaller forage fishes than Tricolored Herons but similar-sized fish as Snowy Egrets. The coarse-scale trophic composition of Snowy Egret and Tricolored Heron diets did not differ significantly, but Tricolored Herons ate larger forage fishes than Snowy Egrets. Pronounced interannual and intercolony variation in diet composition suggested that Great Egrets and Little Blue Herons switched prey types as hydrologic conditions and habitat availability changed. Conversely, lack of such variation suggested that Snowy Egrets and Tricolored Herons adjusted their foraging tactics to ensure continued encounters with preferred prey despite changing habitat conditions. These results are generally consistent with other published data, help confirm some generalizations about foraging strategies and patterns of niche differentiation among these ecologically similar species, and have implications for managing the Lake Okeechobee ecosystem.
... There is also evidence that smaller fish have higher consumption rates (Buckel et al. 1995). In addition, spatial distribution has been shown to vary among size classes (Werner et al. 1977) potentially as a method of reducing resource competition (see Ross 1986). Therefore, it is plausible that differences in activity patterns may reflect smaller individuals moving more to search for habitat with fewer conspecifics. ...
Article
The trade-off between remaining stationary and being active has consequences for the survival and growth of fishes. Recent advancements in telemetry tools have enabled researchers to assess activity patterns of free-swimming fishes using tri-axial acceleration-sensing acoustic transmitters. This study describes the summer activity patterns of muskellunge (Esox masquinongy) in an 8 km reach of the Rideau River, Ontario between 1 June and 20 August 2010. Acceleration measurements indicated that muskellunge tended to remain inactive for much of the time. The effect of time of day (i.e., diel patterns), water temperature, and fish size were also examined. Activity was lowest at dawn, increased throughout the day, peaked at dusk, and declined at night. Activity also declined above temperatures of 25 °C and was lower for larger muskellunge. A comparison of fish captured with rod and reel versus boat electrofisher failed to reveal a significant difference in behaviour. The results of this study illustrate the utility of accelerometer transmitters for studying the behavioural ecology of free-swimming fishes. The results also confirm that muskellunge are generally sedentary during the summer period, but do exhibit reasonably pronounced diel activity patterns.
... Across all analyses, habitat use was correlated with both traditional morphology and body shape. Habitat segregation among coexisting species is widespread in fishes (Werner et al. 1977;Gorman and Karr 1978;Willis et al. 2005;Kano et al. 2013), although the degree of segregation is likely dependent on habitat availability (Jepsen et al. 1997). The observation that fishes occupying comparable habitats have similar morphologies suggests that certain suites of traits are better adapted to different microhabitats found within streams. ...
Article
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Associations between the morphology of animals and their ecology have contributed to our understanding of phenotypic diversity by helping to relate form and function. Most early studies on fishes used traditional measurements of linear distances on the body or fins to quantify morphological variation among taxa. More recently, geometric morphometric analyses have gained popularity for assessing phenotypic shape variation. Along with new methodologies for quantifying morphological variation, researchers have become increasingly aware of the influence of phylogeny on morphological and ecological traits. Our study, which spanned seven cyprinid genera, assessed the abilities of traditional and geometric morphometric approaches to characterize ecologically relevant morphological variation. Furthermore, we compared morphometric approaches employing two analyses (partial Mantel test and Phylogenetic Canonical Correlation Analysis (PCCA)) that test for correlations among data sets while explicitly accounting for phylogenetic relationships. Traditional morphology and body shape showed similar correlations with habitat use in all analyses. In contrast, only traditional morphology was correlated with diet; however, this was only revealed by the PCCA. Our findings indicated the taxonomic span of species under study and the statistical treatment of data are important factors to consider when choosing between traditional or geometric morphometric approaches. In addition, a better understanding of phylogenetic relationships will improve our ability to establish associations between morphology and ecology.
... Because largemouth bass use was positively correlated with CWH complexity, the patterns observed for bluegill are likely due to predation risk. Bluegill appeared to prefer less complex structure that largemouth were not using or very complex structure, which may have reduced predation risk (Werner et al. 1977). Selection of habitats that reduce predation risk has been shown in aquatic macrophyte and CWH structural refuges (Savino and Stein 1989;Eklov 1997;Sass et al. 2006b). ...
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Lakeshore residential development (LRD) reduces coarse woody habitat (CWH) in lakes resulting in negative effects on fishes. We tested whether the addition of CWH could reverse those effects. We added CWH to Camp Lake, a lake with CWH abundances similar to developed lakes, following 2 years of study of the fish populations in the reference and treatment basins. Both basins were monitored for 4 years following the manipulation. Specifically, we tested for changes in the population dynamics (densities, size-structure, growth), diet, and behavior (habitat use) of bluegill (Lepomis macrochirus) and largemouth bass (Micropterus salmoides). CWH addition had no discernible effect on fish population dynamics. Diet and behavioral responses were more pronounced in the treatment basin. Prey diversity and availability increased. Piscivory increased, with decreased reliance upon terrestrial prey, for largemouth bass. Habitat use was positively correlated with CWH branching complexity and abundance. Our study suggests that negative effects observed in fish populations through CWH reductions cannot be reversed in the short-term by adding CWH. We recommend that regulations governing the LRD process be protective of CWH.
... Nevertheless, this hypothesised general depth-related distributional pattern of S. flindersi is the same as the reported life history of other sillaginid species, including S. bassensis [8], S. vittata [37] and Sillaginodes punctata [11,12]. Many species of fish utilize different depths of water during particular life-history stages [46][47][48], which is a potential mechanism to reduce intraspecific competition for resources among different length and age cohorts [49,50]. Such depth stratification between different cohorts of S. flindersi could be utilized as a management mechanism to provide refuge and reduce any potential trawl-associated mortality of juvenile S. flindersi by closing inshore waters (e.g. ...
Article
This study investigated variability in the growth, length, and age compositions and the rates of mortality of Flinders' sillago Sillago flindersi exploited in a demersal trawl fishery in eastern Australia. Sampling was done over 2 years across three depth strata at two locations approximately 400 km apart. Ageing of sectioned sagittal otoliths indicated that the observed maximum age of females was 6 years and that of males 5 years, that growth was variable and that the von Bertalanffy growth parameters significantly differed according to gender and location. Females attained a greater Linf than males, but males displayed greater k values. The Linf values of both sexes and the mean length-at-age for fish aged 3-5 years were greater at the location of highest latitude. Length and age compositions differed according to depth, with smaller (< 15 cm FL) and younger (< 2 years) fish generally more predominant in the shallow (< 30 m) strata than in the deeper (> 31 m) strata. S. flindersi appear to use the shallow strata as a juvenile habitat, moving to deeper waters as they grow. This depth stratification between cohorts may reduce intraspecific competition and could potentially be used as a spatial management tool to reduce any fishing-associated impacts on juveniles. Fish between 1 and 3 years old dominated the age compositions of populations combined across all depths, with estimated total mortality ranging between 2.24 and 2.40. Fishing mortality ranged between 1.54 and 1.70 and was more than twice the derived natural mortality. Exploitation rates were approximately 0.70, indicating that the species was heavily fished.
... Indeed, because they are interfacing aquatic and terrestrial systems, littoral zones have a greater heterogeneity of physical structure (Schmieder 2004;Zohary & Ostrovsky 2011), habitat diversity, and greater trophic resources than pelagic areas (Pierce, Rasmussen & Leggett 1993). Consequently, the littoral zone of reservoirs is crucial for the functioning of the biological cycle of many species and provides shelter for a high biodiversity (Keast 1985;Savino & Stein 1989;Werner et al. 1977). Thus, even if the natural pattern of WLFs can be considered to enhance the productivity and biodiversity of aquatic ecosystems in some conditions (Gafny & Gasith 1999;Wantzen et al. 2008), extreme and untimely water-level fluctuations are often considered as the main hydrological stressor for communities inhabiting the littoral area of reservoirs (Sutela & Vehanen 2008). ...
... Both of these species are similar in meristics, morphology and diet (Berra and Weatherley 1972;Ebner 2006;Baumgartner 2007), which is consistent with hypotheses that competition for habitat may occur between such similar species (Hearn 1987). Habitat and niche partitioning has been observed in fish communities segregating both species and size classes (Werner et al. 1977;Grossman et al. 1998;Crow et al. 2010;Sass et al. 2012). ...
Article
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Many freshwater fish worldwide have been shown to use Structural Woody Habitat (SWH) for a variety of reasons. The mid reaches of the Murray River, a large lowland river in southeastern Australia, was surveyed by boat electrofishing, to investigate the use of SWH type (hollows, rootmass and solids), SWH distance to bank (near bank, intermediate to bank and mid-channel) and the interaction between SWH type and distance to bank. The study found that Murray cod catch per unit effort (CPUE) increased in near-bank areas when hollows were a component of the SWH. The CPUE of trout cod was higher when hollows were present. However, the interactions between distance to bank and hollow SWH were complex and dependent on presence or absence of rootmass. The species-specific interactions between SWH microhabitat and distance to bank found within this study has important relevance for stream managers. The common practice of realigning SWH favours Murray cod over trout cod, which could have negative consequences for the endangered trout cod. More broadly, managers may need to consider a balance of SWH type and where it is placed in the river for the species they are targeting when rehabilitating rivers via the introduction of SWH.
... Naturnahe Litoralzonen bilden ein Mosaik unterschiedlicher Mikrohabitate, die sich in Wasserstiefe, Strömung, Wellenschlag, Bodensubstrat, Vegetation oder anderen Strukturen unterscheiden (CHICK & MCIVOR, 1994). Daher sind die Fischdichte und Artenvielfalt im Litoral in der Regel höher als in anderen Gewässerbereichen (WHITESITE, 1988;SCHIEMER et al., 1995;SMOKOROWSKI & PRATT, 2007 Auch sind die Larven und Jungfische der meisten Arten auf litorale Habitate angewiesen (WERNER et al., 1977;WERNER et al., 1983;COPP, 1992 ...
... Similarly, small bluegills were caught more frequently in the transitional zone at Lake Hope during 2008, but not during 2007. When the data from all reservoirs was pooled, there were no differences in either size or catch frequency among reservoir zones, suggesting that habitat partitioning may be based on different criteria in reservoirs (Gelwick & Matthews, 1990; Eggleton et al., 2005) than has previously been described for natural lakes (e.g., Werner et al., 1977). The lack of repeatability in our findings among years may be indicative of the true nature of reservoirs as a habitat for bluegill. ...
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Reservoirs exhibit gradients in conditions and resources along the transition from lotic to lentic habitat that may be important to bluegill ecology. The lotic-lentic gradient can be partitioned into three functional zones: the riverine, transitional, and lacustrine zones. We measured catch frequency and length of bluegills (Lepomis macrochirus) captured along the periphery of these areas (i.e., in the littoral zone of each functional zone) for four small reservoirs in Southeastern Ohio during the summer months of three years. Catch frequency differed between zones for two reservoirs, but these differences were not observed in other years. There was no relationship between reservoir zone and either standard length or catch frequency when the data for all reservoirs were pooled, but we did observe a bimodal length distribution in all reservoirs. A combination of ecological factors including inter and intraspecific competition, predation intensity, management practices, limnology, and assemblage complexity may be mitigating bluegill distribution and abundance in reservoirs. Therefore, a functional zone (categorical) approach to understanding bluegill ecology in reservoirs may not be appropriate.
... Vision can vary considerably even between closely related species, thus the acuity of the bluegill sunfish cannot be presumed for the common sunfish. As visual abilities reflect features of the habitat, which can differ in Lepomis (Werner et al., 1977;Keast, 1978;Mittelbach, 1984), we may find differences in the visual systems in the sunfish species. Lastly, grating acuity is not a reliable indicator of the minimum object size perceptible, as different physical mechanisms determine how fine grids and how small objects can be, to still be resolved. ...
Article
Vision is considered to contribute to foraging, territorial, and reproductive behavior in sunfish. In these contexts, sunfish need to perceive single targets, such as prey items or body markings from either conspecifics or individuals of other sunfish species, from some distances. We determined the single target acuity of six common sunfish in a behavioral experiment to assess whether the visual abilities of sunfish correspond with behavioral observations or reactive distance measures and thus to assess the limits of vision regarding the mentioned behaviors. Single target acuity for full-contrast single targets amounted to 0.17 (0.13 - 0.32) deg. When contrast was reduced to Weber contrasts of 0.67 and 0.41, single target acuity dropped to 0.34 (0.31 - 0.37) deg, and finally to 0.42 (0.34 - 0.54) deg. Single target acuity would thus allow common sunfish to perceive biologically relevant stimuli at reasonable distances even when contrast is reduced.
... In the aquatic ecosystem where M. salmoides is the top predator, feed that matches the gape size indicates strong predatory tendencies of indiscriminate feeding (Werner et al 1977;Kim and Park 2002;NIER 2011), and to investigate if according to the form of population there are any difference between other total length distribution, were analyzed the point by point measurement of fish, which results in a total of 7 groups of length, of which at the 100 mm the existence of M. salmoides shows significant difference (Figure 7a). At R NIv the full length of 100 -149 mm corresponding to the 100 mm group showed a rate of 65% of all fish (Figure 8a), while at R Iv the appearance of fish with total length from 150 -199 mm of the M A N U S C R I P T ...
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This study was carried out to analyze the difference of fish fauna, ecological indicator characteristics, biological status of other fish population and fish community structures between two groups of reservoir ecosystems along with the invasion of introduced Micropterus salmoides. Six reservoirs were selected and divided into two groups; reservoirs non-invaded and invaded by M. salmoides were RNIv and RIv respectively. Total 28 species 11,519 individuals were sampled in RNIv whereas 19 species 1,925 individuals were sampled in RIv. Korean endemic fish population dominates in RNIv, exotic fish species, especially M. salmoides population dominate in RIv. Sensitive species dominates in RNIv, while tolerant species and carnivore species dominate in RIv. The analysis of total length size distribution showed some difference, particularly in special size group between RNIv and RIv. Also, the analysis of total fish biomass showed a significant difference in accordance with M. salmoides inhabitation. According to the fish community analysis results, as M. salmoides proportion increased, species richness and diversity were decreased. Overall data suggests that the dominant distribution of M. salmoides may influence simplification of the fish fauna, species composition as well as community structure and affect the length distribution and biomass of other fish population negatively.
... Indeed, because they are interfacing aquatic and terrestrial systems, littoral zones have a greater heterogeneity of physical structure (Schmieder 2004;Zohary & Ostrovsky 2011), habitat diversity, and greater trophic resources than pelagic areas (Pierce, Rasmussen & Leggett 1993). Consequently, the littoral zone of reservoirs is crucial for the functioning of the biological cycle of many species and provides shelter for a high biodiversity (Keast 1985;Savino & Stein 1989;Werner et al. 1977). Thus, even if the natural pattern of WLFs can be considered to enhance the productivity and biodiversity of aquatic ecosystems in some conditions (Gafny & Gasith 1999;Wantzen et al. 2008), extreme and untimely water-level fluctuations are often considered as the main hydrological stressor for communities inhabiting the littoral area of reservoirs (Sutela & Vehanen 2008). ...
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Water-level fluctuations are a major function of reservoirs that influence the littoral zone of the lake, and prove to be of high importance for the whole biological communities of lakes. Working on a French hydropower reservoir, we studied the influence of water-level fluctuations on intra-annual variations of littoral habitat availability and their consequences for the structure of fish assemblages inhabiting the littoral zone. As the water level decreased significantly, habitat conditions tended to be much more homogeneous. The proportion of sites with a thin substrate and low slope increased, while submerged vegetation and riparian shade disappeared. The relationship between habitat complexity and fish assemblage changed along the water-level gradient. The habitat effect on assemblage structure was strongest when the water-level conditions were high and very high, and weaker for low and very low water-level conditions. A homogenization of fish assemblages was observed when the water-level condition reached a threshold. These results suggest an effect of water-level management in structuring fish assemblages of the littoral zone of a reservoir due to a decrease of habitat complexity.
... Habitat-scale tracking results also showed a high degree of spatial separation between the two species, indicative of habitat partitioning. Habitat partitioning in fishes has previously been documented for species with overlapping home ranges and resource utilization patterns (Kinney et al. 2011;Knickle and Rose 2014;Werner et al. 1977). In this case, red drum and spotted seatrout occupied different depth zones within the array at Mud Island. ...
Article
Acoustic telemetry was used to examine habitat use and movement of two sympatric gamefishes, red drum (Sciaenops ocellatus) and spotted seatrout (Cynoscion nebulosus), at two spatial scales (habitat and bay) within an estuarine complex. Habitat-scale tracking (~ 1 m–1 km) based on an acoustic positioning system revealed that seagrass was used extensively by both species. Red drum also commonly associated with oyster reef and boundaries between habitat types. Spatial overlap between the two species was limited and indicative of habitat partitioning; red drum were commonly observed in the shallow, inner lagoon and spotted seatrout in the deeper, open bay portion of the array. Conspicuous diel shifts were also observed for spotted seatrout; fish transitioned from seagrass to bare substrate and displayed greater rates of movement at night than day. Bay-scale (1–50+ km) tracking over a two-year period primarily showed limited movement within bays; however, directed bay-scale movements by both species were observed during winter and spring, when a small contingent of individuals moved up to 70 km from original tagging locations. Habitat use and movement were species specific and subject to temporal variation, both diel and seasonal. Habitat-scale connectivity was influenced by seascape structure and water depth, and bay-scale connectivity was generally limited, suggesting the sustainability of these fisheries is likely influenced by local conditions.
... Thus, species that can potentially behave as planktivores, benthivores, herbivores, or detritivores could change their trophic ecology in response to resource availability in different systems (Araújo, Bolnick, & Layman, 2011;Vejříková et al., 2017;Werner et al., 1977). ...
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Generalist fish species can feed on a wide resource spectrum and across trophic levels depending on resource availability and trophic interactions. Crucian carp (Carassius carassius) represents a good candidate species to investigate variation in the trophic ecology of generalist fish as it can be found in highly variable fish communities and its resource use is well documented. In this study, we explored the trophic ecology of crucian carp at the individual and population levels using stable isotope and gut content analysis. We tested if trophic resource use varied according to lake productivity, predation risk, intra- and interspecific competition, or individual fish size. We found that crucian carp resource preference was highly variable among and within lakes. In predator-free lakes, small crucian carp occurred in high densities, showed increased interindividual specialisation, and relied mainly on pelagic zooplankton. In presence of predators, large crucian carp occurred in low densities and included greater proportions of benthic macroinvertebrates in their diet. This shift in resource use was further favoured in productive, shallow lakes where littoral prey were probably abundant. Resource partitioning was an important factor determining crucian carp niche use, as fish had higher trophic position in absence of other cyprinids. Crucian carp showed highly dynamic resource use and food preferences in response to variable environmental conditions. Overlooking complex diet preferences of generalist fish may lead to an oversimplification of freshwater community dynamics.
... Various biotic (e.g., predation, competition, food availability) and abiotic (e.g., temperature, dissolved oxygen (DO), nutrient levels) factors influence fish community composition in lakes (Jackson et al., 2001). Many of these same factors also dictate the spatial distribution of fishes within a lake (Werner et al., 1977). Where these factors vary in both space and time, fish responses are expected to be likewise dynamic. ...
Article
Fishes typically occupy a species-specific temperature range, with their occupied depth being related to the lake’s temperature profile. When a fish’s preferred temperature range coincides with the thermocline, the location of their preferred thermal habitat is influenced by the rise and fall of internal waves, leading to possible changes in fish depth. These internal waves are common in large, stratified lakes, yet we do not know how they affect the spatial distribution and behavior of freshwater fishes. We conducted nighttime hydroacoustic surveys in a large, deep embayment of a large thermally stratified lake to observe whether pelagic fish respond to vertical oscillations of the thermocline caused by internal waves. The coldwater pelagic fish in our study (primarily cisco, Coregonus artedi) typically occupied a narrow vertical band approximately 5–8 m thick and temperatures between 10.8 ± 0.8–13.6 ± 1.6 °C (fishes sized 106–500 mm), just below the thermocline (centered around 15–17 °C). Importantly, the upper bound of fish depth varied in response to vertical thermocline movements associated with internal waves, suggesting fish respond to changes in their physical environment on timescales commensurate with basin-scale internal wave periods (hours to days), to remain within their preferred thermal habitat. Dissolved-oxygen levels were typically above avoidance thresholds of these fish, thus not likely exerting a strong influence on fish location. Our findings emphasize the need to account for internal waves when designing hydroacoustic and netting surveys, as thermocline movements can influence where fish are located.
... These ecological similarities can prevent closely related species from occurring in sympatry due to costs associated with interspecific competition for shared resources and increases in mortality from shared threats (Abrams 1983;Diamond 1986;Ricklefs 2010;Violle et al. 2011). Partitioning habitat (including across gradients of elevation, water depth, etc.) within broader regions of sympatry can alleviate some of these costs by reducing the likelihood of encountering potential competitors and reliance on shared resources (Schoener 1974;Werner et al. 1977;Grace and Wetzel 1981;Diamond 1986;Freeman 2015). Divergence in habitat use is thought to often be the first ecological difference to arise on secondary contact of allopatric species (Diamond 1986;Richman and Price 1992;Schluter 2000;Rabosky et al. 2011;Freeman 2015), potentially reflecting the local availability of diverse habitats (e.g., different elevations) or ease at which species can segregate spatially into distinct habitats without the need to evolve novel traits or alter key existing traits (e.g., body size; Diamond 1986). ...
Article
Habitat partitioning can facilitate the coexistence of closely related species and often results from competitive interference inducing plastic shifts of subordinate species in response to aggressive, dominant species (plasticity) or the evolution of ecological differences in subordinate species that reduce their ability to occupy habitats where the dominant species occurs (evolutionary divergence). Evidence consistent with both plasticity and evolutionary divergence exist, but the relative contributions of each to habitat partitioning have been difficult to discern. Here we use a global data set on the breeding occurrence of birds in cities to test predictions of these alternative hypotheses to explain previously described habitat partitioning associated with competitive interference. Consistent with plasticity, the presence of behaviorally dominant congeners in a city was associated with a 65% reduction in the occurrence of subordinate species, but only when the dominant was a widespread breeder in urban habitats. Consistent with evolutionary divergence, increased range-wide overlap with dominant congeners was associated with a 56% reduction in the occurrence of subordinates in cities, even when the dominant was absent from the city. Overall, our results suggest that both plasticity and evolutionary divergence play important, concurrent roles in habitat partitioning among closely related species in urban environments.
... We evaluated the effects of area and depth for two different groups of species. One group was a defined predator-prey association, comprising three top predators in these systems, largemouth bass Micropterus salmoides, smallmouth bass M. dolomieu and northern pike Esox lucius and four minnows that are common prey species, northern redbelly dace Chrosomus eos, finescale dace C. neogaeus, northern pearl dace Margariscus nachtriebi, and fathead minnow Pimephales promelas, following studies that reported predatory interactions among these species (Crossman, 1962;Jackson, 2002;Jackson et al., 1992;Mauck & Coble, 1971;Werner et al., 1977). For the other group, species with similar habitat requirements (i.e. ...
Article
1. Abiotic factors are recognized for their strong influence on community structure. Habitat diversity is related to resource availability that influences species richness and abundance. In lakes, surface area and depth have been used as measures of the size and diversity of habitat, and have strong effects on the structure of entire communities. 2. We tested whether abiotic variables, related to habitat size, influence co‐occurrence patterns of species‐pairs of fishes by analyzing groups of lakes within a specific area and depth categories in two regions in Ontario, Canada. 3. We used null models to obtain co‐occurrence patterns and standard effect sizes for each species pair within each area and depth category. We estimated standard effect sizes relative to lake area or depth and determined whether species co‐occurrence patterns change systematically as these measures of habitat increase. We evaluated groups of species where factors like predation and habitat filtering have been shown to structure those assemblages, and we tested whether area and depth alter the species associations and our interpretation of these relationships. 4. We found significant differences between the observed and expected distributions of regression slopes relating co‐occurrences to area and depth in both regions across all species, which indicated an overall strong influence of both variables on the overall co‐occurrence patterns. We observed a significant negative trend of the co‐occurrence patterns across lake area categories for predator‐prey species, indicating that the effect of predation was stronger in smaller lakes, but it was reduced in larger lakes, possibly due to increased habitat and resource availability. We show that pooling results as done in standard community null models can lead to Type II errors due to the “cancellation” of opposing ecological signals. 5. Our results demonstrate the effect of environmental variables on species co‐occurrence patterns, but the divergent results obtained between geographic regions suggest that such patterns are context‐dependent. This study emphasizes the importance of considering abiotic factors in null models of species co‐occurrence to obtain reliable and detailed information about the association patterns between species.
... Assessing interspecific and intraspecific habitat partitioning between species and among conspecifics may clarify inferences about habitat selection (e.g. Bañuelos et al. 2008;Alves et al. 2013); both inter-and intraspecific habitat partitioning are widespread across taxa and between sexes (Burger et al. 1977;Werner et al. 1977;Cumming et al. 1996). Several hypotheses have been proposed to explain sexual habitat segregation including the predation risk hypothesis developed for ungulate species (Bowyer 2004;Ruckstuhl 2007). ...
Article
Context. Inter-and intraspecific habitat partitioning is widespread across taxa, yet limited information is available on differences in intraspecific habitat selection by same-sex individuals among differing reproductive states. Understanding habitat selection by conspecifics of different reproductive states may help optimise conservation efforts, particularly for gallinaceous bird species such as greater sage-grouse (Centrocercus urophasianus), which are long-lived but have only moderate reproductive rates. Aims. We predicted that habitat use differed between grouse under different reproductive states and that reproductive investment decreased survival of adults in summer. Methods. We compared habitat characteristics used by brood-rearing and broodless female sage-grouse and evaluated the influence of reproductive investment and habitat use on survival of adult females. Key results. We found that brood-rearing and broodless female sage-grouse partitioned habitat at micro-and macrohabitat scales. Broodless females were more likely to survive the summer. Conclusions. Our findings suggest reproductive state variability in habitat selection by female sage-grouse. Broodless females were roosting and foraging in concealed habitats with intermediate visual obstruction and annual vegetation productivity, but less food forb availability compared with early and late brood-rearing females. In contrast, brood-rearing females likely selected more herbaceous understoreys to predictably maximise foraging opportunities and promote growth of their chicks, which appeared to mitigate the influence of reproductive costs on summer survival, particularly during the late brood-rearing period. Implications. Survival of adult females is critical for population persistence of sage-grouse and other long-lived Galliformes, yet conservation efforts generally focus on habitats used during nesting and brood-rearing. Our results suggest that habitat partitioning is a potential risk-aversion strategy where individuals across different reproductive states likely select habitats to maximise their survival. Conservation efforts should focus on conserving habitats used by both brood-rearing and broodless sage-grouse to ensure population persistence.
... Neotropical fish can colonise a range of different subterranean habitats with distinct physical characteristics (Trajano and Bichuette 2010). Habitat characteristics have been considered as the primary foundation on which biological communities are organised (Schoener 1974); many researchers have sustained this generalisation for fish communities as well (Gibbons and Gee 1972;Werner et al. 1977;Schlosser and Toth 1984). However, no study has examined the effects of the characteristics of the physical habitat on the composition of fish fauna in Brazilian streams draining karst landscapes. ...
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In the present study we examined surface and subterranean sites in order to compare the fish fauna composition and characteristics of the physical habitat in a stream located in a Neotropical karst landscape at the São Francisco River basin, Minas Gerais State, Brazil. We investigated the effects of physical habitat characteristics related to river morphology, substrate composition, wood and canopy cover on the fish community and investigated whether subterranean habitats have additional effects responsible for shaping the fish community structure. During the sampling period (dry season; July 2012), 28 species distributed in 3 orders and 9 families were collected (773 individuals in total). Characiformes was the most diverse group in the studied area, with 16 registered species (57% of the sampled fauna). We did not find cave-adapted fish species during the study, although four non-troglomorphic species (two Characiformes and two Siluriformes) were sampled exclusively in the cave. The species composition was possibly affected by environmental differences, showing distinct patterns between the five sites studied. Canopy cover and the percentage of organic matter on the streambed accounted for most of the variation observed in the fish fauna composition (distance-based linear matrix: adjusted R² = 0.56; P = 0.02). In the system studied, Siluriformes have a greater chance of occupying subterranean habitats, with higher relative abundance and richness inside the cave sites. We believe that number, size and position of subterranean spaces within a karst watershed have additional effects on fish community composition through their selective pressure on species traits.
... However, the net caloric value of Bluegill and Gizzard Shad as prey for Largemouth Bass is dependent on energy expended during capture. The overlap in littoral habitat between Bluegill and Largemouth Bass suggests that Bluegills are more easily attainable forage for Largemouth Bass than are the primarily pelagic Gizzard Shad (Werner et al. 1977). Although Gizzard Shad are important diet items to Largemouth Bass in larger impoundments, complex fish communities common to these systems typically include pelagic predators that prevent Gizzard Shad from becoming overpopulated (Timmons et al. 1980;Irwin et al. 2003). ...
Article
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Gizzard Shad Dorosoma cepedianum are commonly manipulated as a prey species in the United States but are widely viewed as undesirable in small impoundments because of direct and indirect effects on desirable sport fishes. Montgomery State Fishing Lake in southeastern Kansas became populated with Gizzard Shad during a flood event in 2007, and subsequent monitoring efforts indicated the Bluegill Lepomis macrochirus population was negatively affected. Remedial action involving reservoir dewatering and application of rotenone (target concentration of 7.5 μg/L) was conducted during the winter of 2013–2014, and responses of Bluegills and Largemouth Bass Micropterus salmoides were monitored for 3 years posttreatment. Gizzard Shad were not extirpated following treatment, but their relative abundance decreased 99.8%. Relative abundance of age-0 Bluegills and Largemouth Bass immediately increased following treatment in 2014 but decreased to pretreatment levels in 2015 and 2016. Conversely, growth of age-0 Bluegills decreased in 2014, but increased to pretreatment levels in 2015 and 2016. Growth of age-0 Largemouth Bass slightly decreased following treatment. Growth between the development of the second and third annulus did not differ among years for either species. Body condition of stock-length Bluegills and stock-length Largemouth Bass was greatest in 2012 but declined in subsequent years. These results suggest that, contrary to previously published studies, the reduction of Gizzard Shad had minimal effect on Bluegill and Largemouth Bass populations in Montgomery State Fishing Lake. However, intraspecific, density-dependent functions might have masked true responses of Bluegill and Largemouth Bass growth and body condition to Gizzard Shad reduction. Managers should understand that Gizzard Shad removal or reduction can have variable effects in aquatic systems and should be cognizant of potential outcomes and how those might affect fish populations and associated fisheries.
... Studies focusing on droughtdriven littoral habitat reduction and its influence on fish populations are limited to littoral fish species (Gaeta et al., 2014), which is appropriate in small lakes where littoral zones comprise a large proportion of total lake area. However, a knowledge gap exists in our understanding of the potential influence of drought-driven littoral habitat loss in large lakes whose littoral zones comprise a relatively small proportion of total lake area; specifically where species composition may segregate into pelagic, benthic, and littoral species (Keast & Harker, 1977;Werner et al., 1977). Furthermore, little is known about the effects of littoral habitat loss on species that use littoral zones for limited portions of their life cycle, such as reproduction (Gasith & Gafny, 1990). ...
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• Multiyear drought is projected to increase in frequency and duration in arid and semiarid regions across the world, threatening native species and ecosystem function. The effects of multiyear drought are often exacerbated by human water use for consumption, energy production, and agriculture, which, in lentic ecosystems, manifest in reduced lake elevation and altered habitat for aquatic species. • Here, we demonstrate that decreasing lake levels, associated with drought and water management, reduce the availability of littoral cobble habitat to fishes by creating an elevation‐explicit littoral habitat map. We combined long‐term fish catch data and a lake elevation time series with our elevation‐explicit littoral habitat map to test whether fish species population demographics are related to drought‐driven changes in littoral habitat. • We surveyed the littoral zone of Bear Lake, Utah and Idaho, U.S.A., from full pool to a depth of >12 m, totalling 94.86 km² surveyed. As lake elevation decreased >6 m from full pool to the lowest historical elevation, the area of littoral cobble decreased by >97%. Bear Lake sculpin (Cottus extensus, Cottidae), a cold‐water fish species which relies on cobble for reproduction, catch per unit effort decreased by >75% with littoral cobble, and year class strength declined by as much as 86%, but varied across age. • We predicted the response of age‐0 to age‐4 sculpin under high and low cobble availability. Our simulations predict a 60%–85% decline in juvenile sculpin CPUE (age‐2 and younger) when cobble availability decreases from the 95th to 5th percentile. • Our study provided a unique opportunity to identify quantitative linkages between climate‐driven littoral habitat loss and an ecologically important profundal fish species, expanding our understanding of potential future pathways through which climate change may affect lentic ecosystems and fishes.
... Beyond wind, similar responses to biotic conditions may structure synchrony between species. Black crappie and bluegill responded similarly to largemouth bass removals in Alabama lakes (McHugh, 1990), and juveniles of both species share similar habitat and trophic niches (Holland and Huston, 1985;Knights et al., 1995;Werner et al., 1977). Thus, a combination of within-lake interactions and regional climatic patterns may result in similar population dynamics between these two species, where conditions benefitting black crappie recruitment, a goal of fishery biologists seeking to improve fisheries for this recreationally popular species (Boxrucker and Irwin, 2002), may also benefit bluegill populations. ...
Article
Spatially-correlated abiotic and biotic conditions can potentially induce synchrony in the dynamics of disparate populations or species. However, such potential synchrony among species or populations may be tempered by dynamics operating at finer temporal and spatial scales, as well as species-specific responses to environmental conditions. We examined within-and among-species synchrony in year-class strength across 130 lakes in northern Indiana over 30 years to evaluate the relative scale of potential synchrony and its possible ecological mechanisms in five recreationally important fish species: black crappie (Pomoxis nigromaculatus), bluegill (Lepomis macrochirus), largemouth bass (Micropterus salmoides), redear sunfish (L. microlophus), and yellow perch (Perca flavescens). Bluegill and black crappie recruitment was significantly positively correlated when the species coexisted, and relative year-class strength of both species was positively related to mean annual wind speed. However, there were few other instances of recruitment synchrony between or within species, regardless of whether synchrony was assessed within or among lake systems. In addition, habitat similarity and regional weather patterns also played a limited and inconsistent role in shaping recruitment strength or synchrony in these small inland systems. These results suggest that fish recruitment dynamics in small, inland systems are most often a function of system-specific biotic interactions that mask limited input from broader climatological influences, and that understanding recruitment in small lakes will require examinations on appropriately fine spatial and temporal scales.
... Furthermore, no differences were detected in vegetation communities or substrate composition between zones. These habitat features are considered more important in influencing space use and residence patterns in warmwater fishes, compared with water column depth (Keast et al., 1978;Keast & Harker, 1977;Werner et al., 1977). ...
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Research has identified numerous conservation benefits attributed to the use of marine protected areas (MPAs), yet comparatively less is known about the effectiveness of freshwater protected areas (FPAs). This study assessed multiple long‐standing (>70 years active) intra‐lake FPAs in three lakes in eastern Ontario, Canada, to evaluate their potential conservation benefits. These FPAs were intended initially to protect exploited populations of largemouth bass (Micropterus salmoides (Lacépède, 1802)), but since their establishment no empirical data have been collected to evaluate the effectiveness of FPAs for protecting bass or the broader fish community. A comparative biological census of fish species abundance, biomass and species richness was conducted using snorkelling surveys within FPAs, along the bordering transition zones, and in more distant non‐protected areas of the lake that had similar habitats to the FPAs. In general, the FPAs yielded benefits that were most obvious (in terms of abundance and biomass) for the focal protected species (i.e. largemouth bass) as well as several shiner species. Largemouth bass and shiner abundance and biomass were highest in the FPA, lowest in the distant non‐protected areas, and intermediate in the transition zone. Species richness was also highest in the FPAs in two of the three lakes. Collectively, these results support the use of FPAs as a viable and effective conservation strategy that extends beyond simply limiting the exploitation of a target species. Beyond the benefits afforded to fish within the FPA, evidence of spillover in adjacent areas was also observed, which is promising. Additional research is needed on the effectiveness of FPAs in a variety of regions and water‐body types facing various threats in an effort to understand when, where and how to best use FPAs to benefit aquatic biodiversity.
... Despite its diversity and importance, we are not aware of any long-term study (but see Brosse et al., 2007 for within-season studies) focussing on the abundance and biomass dynamics of the juvenile and small fish community in the shallow littoral zone. Hence, our study fills an important gap as knowledge of the dynamics of this community is essential for the understanding of fish recruitment and overall community dynamics (Keast & Harker, 1977;Northcote, 1988;Werner et al., 1977). ...
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1. The littoral zone of lakes is used as spawning, shelter, or feeding habitat for many fish species and hence is of key importance for overall lake functioning. Despite this, hardly any studies exist examining the long-term dynamics and response of the littoral fish community, composed mostly of juvenile fish, to environmental change. Here, we study the response of total catch per unit effort (CPUE) and individual species CPUE of such a community to 17 years of oligotrophication and examine whether the species responses can be characterised as synchronous or asynchronous. 2. We analyse a data set of beach seine catches carried out during morning and twilight , late spring and late summer at three sites in large and deep Lake Constance from 1997 to 2014. Generalised additive mixed models were used to explore changes in CPUE of the overall community and of the most frequently occurring species, and Kendall's W test was applied to examine whether the dynamics of fish species were synchronous or asynchronous. 3. Species-specific and total CPUE strongly differed between morning and twilight and between spring and summer indicating an important role of behavioural and life cycle adaptations of species for CPUE. In addition, also the CPUE of some species seeking shelter behind larger stones was lower at sites without these. 4. Total CPUE did not decline suggesting the overall abundance of littoral fish was resilient to declining nutrients. In contrast, fish community composition changed strongly during the study period due to increases in some species (dace, loach, perch) and decreases in others (bream, burbot, chub, ruffe), indicating response diversity of fish to oligotrophication. The type of community dynamics was scale-dependent, whereby significantly synchronous dynamics according to Kendall's W were observed when taking seasonal variability into account. In contrast, significantly asynchronous species dynamics were observed when only
... Density-dependence leads to intense competitive interactions in many organisms, including reef fishes (Bonin et al., 2015). We believe that competition for shelter could account for the observed pattern, since leaves and branches of the macrophytes banks in tropical rivers attain high structural complexity and are intensely used by small characins to shelter from predators (Werner et al., 1977;Savino, Stein, 1989;Suarez et al., 2013). The main predators to which these fish are exposed in daylight are visually oriented birds and predatory fishes such as Salminus brasiliensis (Cuvier, 1816). ...
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This study integrates laboratory and field results to interpret habitat use and switching by individual bluegill sunfish (Lepomis macrochirus). Prey handling and search times for the bluegill were determined from laboratory feeding experiments at different prey sizes and densities in open water and sediment habitats. Relationships were then constructed to predict the expected return per unit time foraging in these habitats. Experience (learning) was found to increase foraging efficiency up to fourfold over the course of six to eight foraging bouts. A population of 225 bluegills was then introduced into a pond consisting predominantly of open water and sediment habitats. This population exhibited several habitat switches as resources declined during the 3-mo experiment; in addition, the population split over a 5-wk period, with individuals specializing on one habitat or the other. These specialists were considerably more successful than habitat generalists as measured by average amount of food in the stomachs. Return rates estimated from the laboratory experiments indicated that the two habitats were nearly equal in foraging profitability. The individual specialization indicated that learning and mutually interfering foraging mechanisms were involved in the species' use of the two habitats. The results suggest that learning and sampling are important aspects of both habitat use and the specialization of individuals within a population.
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Fishes moving onto the surface of a tidal freshwater marsh from an adjacent stream were sampled with flume nets in spring through autumn for 2 yr. Significantly higher numbers were found at sites adjacent to shallow-sloped depositional banks than at sites adjacent to deeper, steeper sloped erosional banks of the stream. Marsh surface features appeared similar, so explanations for this apparent habitat selection were sought in the subtidal portion of the stream. To determine whether the relative abundance of benthic invertebrate prey differed in the two environments, litter bags were placed in the subtidal for 4 wk. Despite higher numbers of invertebrates in erosional zones, both the wet biomass per sample and the mean wet biomass per organism were significantly greater in depositional sites. To test the hypothesis that invertebrate food is more available to fishes in the depositional subtidal, banded killifish (Fundulus diaphanus) were placed in feeding enclosures in both depositional and erosional subtidal habitats in two streams. These fish obtained significantly more food in the shallow depositional subtidal. To test the hypothesis that predation pressure differs with subtidal geomorphology, mummichogs (Fundulus heteroclitus) were tethered on the first half of the rising tide in both depositional and erosional environments in three creeks. Significantly more mummichogs disappeared from tethers and were presumed taken on erosional banks. We conclude that two mechanisms operate in the stream subtidal to give rise to the greater fish abundance at marsh surface sites adjacent to depositional areas. At low tide, when small fishes are confined to creek channels, they select shallow depositional habitats where (1) the availability of benthic invertebrate prey is greatest and (2) predator pressure is less. As the tide rises and inundates the marsh surface, these small fishes seek shelter on the marsh surface adjacent to their preferred low-tide refuge.
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General concepts of larval fish ecology in temperate oceans predominantly associate dispersal and survival to exogenous mechanisms such as passive drift along ocean currents. However, for tropical reef fish larvae and species in inland freshwater systems behavioural aspects of habitat selection are evidently important components of dispersal. This study is focused on larval Atlantic herring (Clupea harengus) distribution in a Baltic Sea retention area, free of lunar tides and directed current regimes, considered as a natural mesocosm. A Lorenz curve originally applied in socio-economics to describe demographic income distribution was adapted to a 20 year time-series of weekly larval herring distribution, revealing size-dependent spatial homogeneity. Additional quantitative sampling of distinct larval development stages across pelagic and littoral areas uncovered a loop in habitat use during larval ontogeny, revealing a key role of shallow littoral waters. With increasing rates of coastal change, our findings emphasize the importance of the littoral zone when considering reproduction of pelagic, ocean-going fish species; highlighting a need for more sensitive management of regional coastal zones.
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The family Centrarchidae includes about 34 species, which all have their native range in North America. In the Netherlands the most ill famous member is Lepomis gibbosus. This in the Netherlands invasive species is the only member of the family with established populations. These populations can be found all over the Netherlands and the species seems to be still expanding. Its negative image is caused by its presence in many isolated water bodies where it has a strong negative impact on the fauna, including rare amphibians such as the common spadefoot (Pelobates fuscus) and the European tree frog (Hyla arborea). Because of this impact a wholesaler has decided stop selling this species in 2010. In this study it is shown that another nine species of Centrarchidae should be considered to be potentially invasive. They are all at least available for export in North America and have a high probability of establishment based on their thermal biology: A. rupestris, P. annularis, P. nigromaculatus, L. cyanellus, L. macrochirus, L. megalotis s.l. (L. megalotis s.s. & L. peltastes), M. dolomieu & M. salmoides. When considering possible climate change in the period 1990-2050 L. auritus should be included in this list. These species are all flexible in their habitat preferences and are likely to find suitable habitats in most regions in the Netherlands. With these centrarchids known to be good dispersers, it is likely that they will spread relatively easily after establishing reasonable populations. The family Elassomatidae, which is also reviewed as they might be a potential substitute for centrarchids in trade, is considered to be of no risk as they are unlikely to survive Dutch winters. Like L.gibbosus also other Centrarchidae are likely to affect ecosystems mainly by predation (amphibians, smaller fish species, damselflies, etc.) and competition with other predatory fish. Especially ecosystems, lacking comparable native predatory fish species prior to the establishment of such an exotic centrarchid, are susceptible to significant ecological impact. Centrarchidae have not been reported to be vectors for parasites or diseases of special concern. The establishment of larger centrarchid species will have a small, positive social and economic impact to commercial fisheries, the angling society and related business. When established, centrarchid populations can in most instances only be eradicated with rigorous measures like dewatering or the use of piscicides. Obviously, the prevention of entries and further spread reduces the need for such actions. The major components of prevention are banning of potential invasive species from trade and educating the public about the impact of centrarchids.
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Biotic interactions and niche processes are fundamental determinants of community structure and species co‐occurrence. Most studies of species co‐occurrence have focused on negative association patterns (segregation presumed to arise from competition), often ignoring positive aggregations, although positive and negative associations may arise from multiple mechanisms. We used a pairwise approach to identify co‐occurrence patterns of 76 fish species across almost 9500 lakes, followed by a meta‐analytic approach to compare the co‐occurrence pattern of each species pair across watersheds and determine their cumulative species associations. Biological information relating to species’ phylogeny, habitat preferences, and diet was used to group species into relevant subsets in order to test community assembly processes of competition, predation, and habitat filtering. We found consistent non‐random patterns of co‐occurrence in nearly half the species pairs and more extremely aggregated than segregated species pairs. Observed co‐occurrence patterns indicated the importance of shared habitat requirements and predation, rather than competition, driving positively aggregated and negatively segregated species associations, respectively. Our meta‐analytic approach incorporating important biological attributes permitted the testing of specific mechanisms of community assembly, providing novel insights into the major determinants of fish community structure and their generality across a vast set of lakes.
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Die ökologischen Effekte einer mosaikartigen winterlichen Rohrwerbung wurden untersucht. Dabei konnten der Bestand selber, die Vegetation, Fische, Amphibien und Vögel berücksichtigt werden. Phragmites-Halme wachsen nach eine Mahd in höheren Dichten, bleiben aber etwas kürzer. Durch die Methodik kam es an den seeseitigen Ausdehnungsfronten der Röhrichte zu mahbedingten Schäden am Schilf. Für die Fischbestände war kein Einfluss der Wintermahd erkennbar. Amphibien profitierten von der Mahd, und hielten sich auf den geschaffenen Flachwasserflächen auf. Bei den Vögeln zeigte sich eine erhöhte Artenvielfalt nach der Mahd, die freien Flachwasserflächen wurden als Habitat von vorher abwesenden Arten angenommen. Bei einer Schilfbrüter-Art zeigte sich eine Abnahme der vorher hohen Bestandsdichte.
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We report the first occurrence of an actinopterygian fish from the Lower Jurassic Navajo Sandstone, discovered in the Grand Staircase-Escalante National Monument in southern Utah, U.S.A. The site contains multiple individuals, preserved within an interdune deposit, possessing the elongate modified dorsal scales usually characterizing semionotiform fishes. The presence of moderately sized fish provides further evidence that interdune oases were occasionally persistent environmental habitats within the greater Navajo dune system, and that the paleobiota is still woefully undersampled. Additionally, this site could help fill a gap in the actinopterygian fossil record between the patchy Lower Jurassic and better-known Middle Jurassic documentation of western North America.
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Variability and reliability of counts of fish made by divers in sections of two British Columbia rivers are examined. Repeated counts of several species of fish by a team of divers in a stream section are reasonably homogeneous, and not markedly different from total numbers subsequently recovered by poisoning. Diver counts of large spawning rainbow trout also agree closely with those made in areas with good visibility from the river bank or from helicopter. Under suitable conditions a diver team can rapidly census the fish population of long stretches of stream and obtain estimates of species composition and abundance in types of habitat difficult or impossible to sample by usual methods.
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