Galaxias maculatus

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Gustavo P. Viozzi - One of the best experts on this subject based on the ideXlab platform.

  • Pathology associated with larval Eustrongylides sp. (Nematoda: Dioctophymatoidea) infection in Galaxias maculatus (Actinopterygii: Galaxiidae) from Patagonia, Argentina
    International journal for parasitology. Parasites and wildlife, 2019
    Co-Authors: Silvia Elizabeth Guagliardo, Gustavo P. Viozzi, Norma Brugni
    Abstract:

    Abstract Helminth infections within tissues tend to be subjected to a host response that can include encapsulation and melanization to isolate the parasite. The effectiveness of this response depends on the host species. During a survey of parasites of the native fish, Galaxias maculatus, we found conspicuous, strongly melanized exterior cysts located in the caudal peduncle of the fish. Dissection of these cysts exposed larval nematodes whose morphometrical features allowed their identification as Eustrongylides sp. Species of this genus are distributed worldwide. Galaxias maculatus was previously reported as second intermediate host to Eustrongylides sp. larvae, and the aquatic bird Podiceps major was cited as definitive host of Eustrongylides tubifex in Andean Patagonian lakes. The site of infection in the fish, and the host's response are unique among infections by larvae of Eustrongylides sp. in fishes, so the objective of this study was to describe the histological injury caused by larvae of the genus Eustrongylides parasitizing G. maculatus. Samples of fish were taken near the shore of Gutierrez lake, in northwestern Patagonia. Some larval morphometric features were described to confirm the identity of larvae to generic level. Histopathological analysis (tissues sectioned at 5–7 μm, stained with Hematoxylin and Eosin, and Masson's Trichrome) of the caudal peduncle revealed almost complete disappearance of the epaxial musculature due to compressive atrophy and a chronic inflammatory response, associated mainly with a dense fibrotic capsule and an intense melanic deposit. This is the first description of the histopathology of an external cyst caused by Eustrongylides sp. larvae in fishes.

  • Myxidium biliare sp. n. (Myxozoa) from gall bladder of Galaxias maculatus (Osmeriformes: Galaxiidae) in Patagonia (Argentina)
    2016
    Co-Authors: Gustavo P. Viozzi, Veronica R Flores
    Abstract:

    Abstract. Myxidium biliare sp. n., a new myxosporean species parasitizing the gall bladder of Galaxias maculatus (Jenyns), in Patagonia, is described. Its coelozoic plasmodia were floating free in the bile. Spores are fusiform 13.7 ± 0.9 µm long and 6.9 ± 0.6 µm wide, with rounded ends in frontal view and slightly pointed ends in sutural view; shell with ridges and sinuous sutural line. Both maximum prevalence and maximum percentage of immature plasmodia occurred in summer. In winter the prevalence and the percentage of immature plasmodia fell to their lowest values. Prevalence was independent of host sex but increased with host length. Prevalence in 15 Patagonian Andean lakes (situated from 39°25’S to 41°30’S) ranged between 4.2 % and 70%. Four species of Myxobolus Bütschli, 1882 have been recorded from Galaxias maculatus (Jenyns) throughout its distribution range. In New Zealand, Hine (1976) described Myxobolus iucundus Hine, 1976 parasitizin

  • la estructura de las comunidades de helmintos de Galaxias maculatus osmeriformes galaxiidae en diferentes sitios de un lago de la patagonia argentina
    Ecología Austral, 2015
    Co-Authors: María Valeria Fernández, Liliana Semenas, Gustavo P. Viozzi
    Abstract:

    The spatial variation of helminth communities of an aquatic system can be attributed to different biotic and abiotic factors. In South America, this type of studies has not been conducted in freshwater environments. The lake Nahuel Huapi is the largest within the Nahuel Huapi National Park. As it presents a diversity of habitat, this lake offers an ideal environment to identify factors that impact over the helminth communities of Galaxias maculatus (small puyen) at different sites of the lake. In order to analyze these variations, 144 small puyens were captured in five sites of the lake with different environmental characteristics. Community analyses were performed, and composition of communities and abundance of the different species of helminths were related with biotic and abiotic factors of the different sites. The size of the host, shallow littorals with aquatic vegetation, and anthropic impact were the factors that determined the variations in composition and abundance of the component communities of helminths in the prey fish Galaxias maculatus from Nahuel Huapi Lake.

  • metazoan parasites of Galaxias maculatus osmeriformes galaxiidae from argentinean patagonia
    Comparative Parasitology, 2009
    Co-Authors: Gustavo P. Viozzi, Liliana Semenas, Norma Brugni, Veronica Flores
    Abstract:

    A checklist, based on bibliographical records and original data from an extensive survey, is presented for the metazoan parasites of Galaxias maculatus (Jenyns, 1842) in Argentinean Patagonia. The checklist includes 33 metazoan parasite entries: 5 myxozoans, 12 digeneans, 2 monogeneans, 3 cestodes, 2 acanthocephalans, 7 nematodes, 1 copepod, and 1 bivalve. Gyrodactylus sp., Pomphorhynchus patagonicus Ortubay, Ubeda, Semenas and Kennedy, 1991, and Hysterothylacium patagonense Moravec, Urawa and Coria, 1997 are reported for the first time from G. maculatus in South America. Although this checklist enlarges the knowledge of G. maculatus parasites, a large portion of Patagonia remains unexplored, and many of its lakes and rivers have never been surveyed for parasites, especially in the southern part of the region.

  • A new genus of Cystidicolid nematode from the stomach of Galaxias maculatus (Osmeriformes: Galaxiidae) in Patagonia (Argentina).
    The Journal of parasitology, 2009
    Co-Authors: Norma Brugni, Gustavo P. Viozzi, María Valeria Fernández, Rocío Vega
    Abstract:

    During a parasitological survey of Galaxias maculatus (Jenyns) from Patagonian Andean Lakes, specimens of a new species of nematode were collected from the stomach of fish and studied by light and scanning electron microscopy. This species is described as the only member of a newly proposed genus of Cystidicolidae by having oral opening dorsoventrally elongated, 2 lateral pseudolabia, 4 cephalic papillae, stoma (vestibule) elongated, esophagus divided into anterior muscular and posterior glandular sections, and caudal alae in males. Placonema n. gen. (Habronematoidea, Cystidicolidae) is characterized by the combination of the following features: oral opening dorsoventrally elongated demarcated by 4 sclerotized plates and 2 well-developed pseudolabia projected to the buccal cavity, each pseudolabium with conspicuous, conical, anterior protuberances. Four cephalic papillae and deirids simple. Male with caudal alae, area rugosa absent, 4 pairs of preanal papillae, unpaired papilla present on anterior cloacal lip, and 6 pairs of postanal papillae. Larvigerous eggs without filaments. Placonema pataguense n. gen. n. sp. infects the stomach of G. maculatus from Lake Patagua (Patagonia, Argentina) and is the first species of Cystidicolidae described from G. maculatus.

Liliana Semenas - One of the best experts on this subject based on the ideXlab platform.

  • la estructura de las comunidades de helmintos de Galaxias maculatus osmeriformes galaxiidae en diferentes sitios de un lago de la patagonia argentina
    Ecología Austral, 2015
    Co-Authors: María Valeria Fernández, Liliana Semenas, Gustavo P. Viozzi
    Abstract:

    The spatial variation of helminth communities of an aquatic system can be attributed to different biotic and abiotic factors. In South America, this type of studies has not been conducted in freshwater environments. The lake Nahuel Huapi is the largest within the Nahuel Huapi National Park. As it presents a diversity of habitat, this lake offers an ideal environment to identify factors that impact over the helminth communities of Galaxias maculatus (small puyen) at different sites of the lake. In order to analyze these variations, 144 small puyens were captured in five sites of the lake with different environmental characteristics. Community analyses were performed, and composition of communities and abundance of the different species of helminths were related with biotic and abiotic factors of the different sites. The size of the host, shallow littorals with aquatic vegetation, and anthropic impact were the factors that determined the variations in composition and abundance of the component communities of helminths in the prey fish Galaxias maculatus from Nahuel Huapi Lake.

  • metazoan parasites of Galaxias maculatus osmeriformes galaxiidae from argentinean patagonia
    Comparative Parasitology, 2009
    Co-Authors: Gustavo P. Viozzi, Liliana Semenas, Norma Brugni, Veronica Flores
    Abstract:

    A checklist, based on bibliographical records and original data from an extensive survey, is presented for the metazoan parasites of Galaxias maculatus (Jenyns, 1842) in Argentinean Patagonia. The checklist includes 33 metazoan parasite entries: 5 myxozoans, 12 digeneans, 2 monogeneans, 3 cestodes, 2 acanthocephalans, 7 nematodes, 1 copepod, and 1 bivalve. Gyrodactylus sp., Pomphorhynchus patagonicus Ortubay, Ubeda, Semenas and Kennedy, 1991, and Hysterothylacium patagonense Moravec, Urawa and Coria, 1997 are reported for the first time from G. maculatus in South America. Although this checklist enlarges the knowledge of G. maculatus parasites, a large portion of Patagonia remains unexplored, and many of its lakes and rivers have never been surveyed for parasites, especially in the southern part of the region.

  • population dynamics of philureter trigoniopsis monogenea ancyrocephalinae from urinary organs of Galaxias maculatus osmeriformes galaxiidae in a cold temperate andean patagonian lake argentina
    Journal of Parasitology, 2005
    Co-Authors: Gustavo P. Viozzi, Liliana Semenas, Pablo Gutierrez
    Abstract:

    Philureter trigoniopsis parasitizes the ureters and urinary bladder of Galaxias maculatus in Patagonian Andean lakes. To investigate factors associated with variation in the prevalence and intensity of this monogenean, fish were sampled periodically over 2 yr in Lake Gutierrez. Prevalence and mean intensity are higher in smaller fishes than in larger ones. A seasonal pattern was observed, with peak recruitment and peak mean intensity occurring in early spring (September), followed by lows in late summer (January-February). Galaxias maculatus length classes are spatially segregated due to seasonal migrations, so the annual infection cycle is characterized by higher prevalence and intensity from late winter to early summer in the smaller fish from the deep zone of the lake.

  • Population dynamics of Philureter trigoniopsis (Monogenea: Ancyrocephalinae) from urinary organs of Galaxias maculatus (Osmeriformes: Galaxiidae) in a cold temperate andean patagonian lake (Argentina)
    The Journal of parasitology, 2005
    Co-Authors: Gustavo P. Viozzi, Liliana Semenas, Pablo A. Gutiérrez
    Abstract:

    Philureter trigoniopsis parasitizes the ureters and urinary bladder of Galaxias maculatus in Patagonian Andean lakes. To investigate factors associated with variation in the prevalence and intensity of this monogenean, fish were sampled periodically over 2 yr in Lake Gutiérrez. Prevalence and mean intensity are higher in smaller fishes than in larger ones. A seasonal pattern was observed, with peak recruitment and peak mean intensity occurring in early spring (September), followed by lows in late summer (January-February). Galaxias maculatus length classes are spatially segregated due to seasonal migrations, so the annual infection cycle is characterized by higher prevalence and intensity from late winter to early summer in the smaller fish from the deep zone of the lake.

  • Acanthocephalus tumescens (Acanthocephala, Echinorhynchidae) in Galaxias maculatus (Pisces, Galaxiidae) of Lake Gutiérrez, Patagonia, Argentina
    The Journal of parasitology, 2000
    Co-Authors: Ana Trejo, Liliana Semenas, Gustavo P. Viozzi
    Abstract:

    The seasonal distribution of Acanthocephalus tumescens (Acanthocephala: Echinorhynchidae) among Galaxias maculatus (Pisces: Galaxiidae) in Lake Gutierrez was studied from March 1994 to June 1996. Acanthocephalus tumescens always occurs in the intestine, has an overdispersed frequency distribution, a similar proportion of sexes, and females are larger than males. Mean intensity and prevalence are low and increase with host length. The pattern of the infection shows seasonality, with recruitment in winter and a reproductive period during spring–summer.

Ana Trejo - One of the best experts on this subject based on the ideXlab platform.

Daniel E. Ruzzante - One of the best experts on this subject based on the ideXlab platform.

  • Seventeen novel microsatellite markers for the southern hemisphere fish Galaxias maculatus
    Conservation Genetics Resources, 2014
    Co-Authors: Iván Vera-escalona, Livia E. Anthes, Ian G. Paterson, Daniel E. Ruzzante
    Abstract:

    Galaxias maculatus is a widely distributed fish with diadromous and resident populations throughout Gondwanan regions. We present 17 novel microsatellite markers that were tested on 44 individuals from one lacustrine population in Patagonia. We found ten poly- morphic markers and seven monomorphic markers in the population under analysis. The number of alleles in the polymorphic loci ranged from 3 to 10. The observed het- erozygosities ranged from 0.11364 to 0.65909, and the expected heterozygosities ranged from 0.15204 to 0.63898. These microsatellite markers are currently being used in landscape genetic studies of G. maculatus from Patagonia.

  • Genetic and phenotypic differentiation among Galaxias maculatus populations in a Patagonian postglacial lake system
    Biological Journal of the Linnean Society, 2012
    Co-Authors: Cecilia Carrea, Juan Pablo Barriga, Victor E. Cussac, Daniel E. Ruzzante
    Abstract:

    Understanding the influence of landscape features on population differentiation is fundamental to evolutionary biology studies. We examined spatial patterns of genetic and phenotypic variability among Galaxias maculatus populations in a complex of four postglacial lakes in northwestern Patagonia differing in size and connectivity among them. A hierarchical Bayesian analysis grouped the individuals collected from eleven localities into three genetic clusters, first defining the populations of the two large lakes and separating the two small lakes in subsequent analysis. Genetic structuring was restricted within large lakes. It is known that the larval stage of Galaxias maculatus migrate to the limnetic zone of Patagonian lakes, possibly exerting an homogenizing effect on gene flow within lakes. Gene flow asymmetry and divergences among lakes can be explained by a combination of landscape characteristics and the presence of predators in the short streams that connect them. Individuals from the small lakes are the most divergent morphologically and genetically. The population in the isolated Redonda Lake, exhibits meristic differences as well, suggesting strong drift and environmental effects. This population is likely to have been isolated following the decline in water level of a paleolake that existed in this region approximately 13.2 kya BP. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ••, ••–••.

  • Ten novel microsatellite loci characterized for a remarkably widespread fish: Galaxias maculatus (Galaxiidae)
    Molecular ecology resources, 2009
    Co-Authors: Cecilia Carrea, Ian G. Paterson, Victor E. Cussac, Daniel E. Ruzzante
    Abstract:

    Ten polymorphic microsatellite markers (five tetra-, one compound tetra-, one octa- and three dinucleotides) were isolated and characterized for Galaxias maculatus, a fish species widely distributed in the Southern Hemisphere. Markers were tested in 89 individual samples from a single location and the number of alleles ranged between 2 and 28. Observed and expected heterozygosities ranged from 0.103 to 0.910 and 0.098 to 0.935 respectively. No evidence was detected for either linkage disequilibrium (P-values > 0.05 for each locus pair) or deviations from HWE (P-values > 0.05 for every loci).

Stephen E. Swearer - One of the best experts on this subject based on the ideXlab platform.

  • smell no evil copper disrupts the alarm chemical response in a diadromous fish Galaxias maculatus
    Environmental Toxicology and Chemistry, 2016
    Co-Authors: Oliver R. B. Thomas, Nicole C. Barbee, Kathryn L. Hassell, Stephen E. Swearer
    Abstract:

    Fish, at all life stages, utilize olfactory information in the decision-making processes essential to survival. Olfaction is a sensitive sensory process, and toxicants within urban aquatic environments can have destructive or depreciating effects. In the present study, the authors exposed Galaxias maculatus, a native fish commonly found in urban waterways throughout southeastern Australia, to 1 of 5 ecologically relevant copper (II) chloride concentrations (<1 μg/L, 1 μg/L, 6 μg/L, 8 μg/L, 18 μg/L) for 16 h. After exposure, the authors tested the response of individual fish to 1 of 3 stimuli: a conspecific skin extract containing a stress-inducing alarm chemical odor, a conspecific odor, and distilled water as a control. Stress responses were quantified through behavioral assays. The authors found evidence for distinct changes in behavioral response with increasing copper concentration and a marked difference in response between control fish and fish exposed to the alarm chemical odor. Copper, even at relatively low concentrations, can have a significant effect on the stress response behavior shown by G. maculatus. Environ Toxicol Chem 2016;35:2209-2214. © 2016 SETAC.

  • Smell no evil: Copper disrupts the alarm chemical response in a diadromous fish, Galaxias maculatus
    Environmental toxicology and chemistry, 2016
    Co-Authors: Oliver R. B. Thomas, Nicole C. Barbee, Kathryn L. Hassell, Stephen E. Swearer
    Abstract:

    Fish, at all life stages, utilize olfactory information in the decision-making processes essential to survival. Olfaction is a sensitive sensory process, and toxicants within urban aquatic environments can have destructive or depreciating effects. In the present study, the authors exposed Galaxias maculatus, a native fish commonly found in urban waterways throughout southeastern Australia, to 1 of 5 ecologically relevant copper (II) chloride concentrations (

  • Estuarine geomorphology and low salinity requirement for fertilisation influence spawning site location in the diadromous fish, Galaxias maculatus
    Marine and Freshwater Research, 2010
    Co-Authors: Andy S. Hicks, Nicole C. Barbee, Stephen E. Swearer, Barbara J. Downes
    Abstract:

    In habitats such as estuaries, which are characterised by large and fluctuating gradients in abiotic variables, finding appropriate habitat for successful spawning and egg development can be critical to a species' survival. We explored how salinity requirements for successful fertilisation may govern the distribution of estuarine spawning habitat for the diadromous fish, Galaxias maculatus, which spawns in inundated vegetation on estuary banks during spring tides. Artificial fertilisation experiments confirmed that successful fertilisation only occurs at low salinities (

  • Characterizing natal source population signatures in the diadromous fish Galaxias maculatus, using embryonic otolith chemistry
    Marine Ecology Progress Series, 2007
    Co-Authors: Nicole C. Barbee, Stephen E. Swearer
    Abstract:

    One of the greatest empirical challenges in studies of marine metapopulations is assess- ing the role of connectivity in maintaining local populations. The use of natural tags in body struc- tures such as otoliths has led to significant improvements in our understanding of dispersal dynam- ics; however, the real knowledge gap remains our ability to identify the origins of dispersing larvae. In the present study we show that embryonic otoliths of a diadromous fish native to southeastern Aus- tralia, Galaxias maculatus, can be used to quantify unique natal elemental signatures and identify potential source populations spread out along a contiguous coastline. Using laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS), we analysed embryonic otoliths from G. maculatus hatchlings from 10 rivers across coastal Victoria, Australia. We found significant differences among rivers in the concentrations of all 8 elements analysed (B, Mg, Mn, Zn, Cu, Sr, Ba, Pb). More impor- tantly, significant differences among rivers in the multi-element signature of hatchling otoliths indi- cate that sites separated by 10s to 100s of km can be discriminated with a high degree of confidence. Our results show that these methods can be successfully applied to examine questions of population connectivity within metapopulations of diadromous species.

  • Avoidance of native versus non-native predator odours by migrating whitebait and juveniles of the common galaxiid, Galaxias maculatus
    New Zealand Journal of Marine and Freshwater Research, 2007
    Co-Authors: Felicity Mclean, Nicole C. Barbee, Stephen E. Swearer
    Abstract:

    Abstract Avoidance of predator odours by migrating Galaxias maculatus was studied in the laboratory using a two‐chamber choice tank. The odours of a native predator (short‐finned eel, Anguilla australis) and an introduced predator (rainbow trout, Oncorhynchus mykiss) were tested on both whitebait (i.e., new recruits) and juveniles. Both whitebait and juveniles exhibited avoidance behaviour when exposed to eel odours. There was no avoidance response from either the whitebait or juvenile G. maculatus when exposed to trout odours, which could suggest differences in the ability of G. maculatus to detect native and introduced predators. Observed negative effects of introduced predators on native species may be owing in part to the absence of innate avoidance behaviour in native prey species.

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