Search results for "taimen"
showing 10 items of 35 documents
Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) differ in their suitability as hosts for the endangered freshwater pearl mussel (Margari…
2017
1. European populations of the freshwater pearl mussel (FPM, Margaritifera margaritifera) have widely collapsed, and despite many types of conservation actions the number of successful restoration trials has remained limited. The goal of this study was to find new aspects for the conservation by investigating whether there are population-specific differences in suitability of Atlantic salmon (Salmo salar) and brown trout (S. trutta) as the hosts for the parasitic glochidium larvae of FPM, depending probably on the historical occurrence of these salmonid species in FPM habitats. 2. We studied the potential host specificity both in the field and in laboratory by exposing salmonid fish to FPM …
The role of salmonid fishes in conservation of the endangered freshwater pearl mussel (Margaritifera margaritifera)
2016
The abundance of freshwater pearl mussels (Margaritifera margaritifera) has declined widely during the past century, and new conservation initiatives are needed. This thesis focused on the relationship between M. margaritifera and its salmonid host required for reproduction of this species. First, by exposing fish experimentally to glochidium larvae of M. margaritifera, different M. margaritifera populations were shown to demonstrate strong differences in their ability to parasitize different salmonid species. Atlantic salmon was clearly a better host for mussels in large river channels, whereas in small headwater tributaries brown trout was the best, or the only suitable, host. These findi…
Quantity and Quality of Aquaculture Enrichments Influence Disease Epidemics and Provide Ecological Alternatives to Antibiotics
2021
Environmental heterogeneity is a central component influencing the virulence and epidemiology of infectious diseases. The number and distribution of susceptible hosts determines disease transmission opportunities, shifting the epidemiological threshold between the spread and fadeout of a disease. Similarly, the presence and diversity of other hosts, pathogens and environmental microbes, may inhibit or accelerate an epidemic. This has important applied implications in farming environments, where high numbers of susceptible hosts are maintained in conditions of minimal environmental heterogeneity. We investigated how the quantity and quality of aquaculture enrichments (few vs. many stones
Taimenen mädin säilyvyys ja alkioiden kasvu Savijoen kipsinlevitysalueella
2019
Pelloille tehtävän kipsinlevityksen vesistövaikutuksia tutkittiin Helsingin yliopiston ja Suomen ympäristökeskuksen yhteishankkeessa ”SAVE - Saaristomeren vedenlaadun parantaminen peltojen kipsikäsittelyllä”. Hanke oli ympäristöministeriön rahoittama hallituksen kärkihanke. Siinä missä kipsin, eli kalsiumsulfaatin, levitys on vähentänyt pelloilta tulevaa fosforikuormitusta, se on toisaalta nostanut pilottialuetta halkovan Savijoen sulfaattipitoisuuden kolminkertaiseksi. Suuren sulfaattipitoisuuden tiedetään olevan haitallista vesieliöille, kuten kaloille. Näin ollen Jyväskylän yliopisto selvitti kipsinlevityksen vaikutuksia taimenen (Salmo trutta) varhaisten elinvaiheiden säilyvyyteen ja ka…
Investigating different migration patterns of Salmo trutta (L.) in the Teno river system using stable isotope analyses
2009
Immunization of trout (Salmo trutta) against freshwater pearl mussel (Margaritifera margaritifera) by duck mussel (Anodonta anatina) glochidia
2013
Freshwater pearl mussel Margaritifera margaritifera is endangered throughout its range of distribution in Europe. In some rivers M. margaritifera may co-occur with the duck mussel Anodonta anatina. Brown trout Salmo trutta serves as suitable fish host for both mussel species. Thus it is possible that exposure of brown trout to A. anatina glochidia might increase resistance of fish against M. margaritifera glochidia. The aim was to test this ‘cross immunity hypothesis’. Brown trout were immunized by duck mussel (Anodonta anatina) glochidia in late May. Then brown trout were challenged by pearl mussel (Margaritifera margaritifera) glochidia in late August after the A. anatina glochidia were d…
Interactions between two parasites of brown trout (Salmo trutta): Consequences of preinfection
2018
Preinfection by one parasitic species may facilitate or by contrast hamper the subsequent penetration and/or establishment of other parasites in a host. The biology of interacting species, timing of preinfection, and dosage of subsequent parasite exposure are likely important variables in this multiparasite dynamic infection process. The increased vulnerability to subsequent infection can be an important and often overlooked factor influencing parasite virulence. We investigated how the preinfection by freshwater pearl mussel Margaritifera margaritifera glochidia could influence the success of subsequent infection by the common trematode Diplostomum pseudospathaceum in brown trout Salmo tru…
Return of the Apex Predator : How Brown Trout (Salmo trutta) Re-Establishment Shapes an Ecosystem
2021
Re-establishment of a declined apex predator fish species in a lake ecosystem may have dramatic effects on other fish and plankton community already inhabiting the ecosystem. We studied mechanistically potential impacts of re-establishment of the brown trout (Salmo trutta) in the west-central European Lake Constance focusing on two commercially important fish species: whitefish and Eurasian perch. We compared simulation model outputs from two versions of an allometric trophic network model for Lake Constance, one with and one without the trout as the apex predator. The re-establishment of the declined brown trout reduced the perch population directly by predation and indirectly by increased…
Interaction between the endangered freshwater pearl mussel Margaritifera margaritifera, the duck mussel Anodonta anatina and the fish host (Salmo) : …
2018
The common duck mussel Anodonta anatina can live in sympatry with—and use the same host, brown trout (Salmo trutta)—as the endangered freshwater pearl mussel Margaritifera margaritifera. Since the glochidia release of A. anatina takes place seasonally earlier than that of M. margaritifera, brown trout can be sequentially exposed first to A. anatina and then to M. margaritifera. Cross-immunity, an immune reaction induced in fish host against glochidia after the infection with glochidia of another mussel species, is possible. Thus, it was studied experimentally if brown trout can be cross immunized against M. margaritifera by earlier infection with A. anatina. In addition, the hypothesis that…
Koukun koon ja väkäsen vaikutus kaloille aiheutuviin vaurioihin, verenvuotoon ja koukun kiinnipysymiseen
2010
Taimen (Salmo trutta, L.) on erittäin suosittu virkistyskalastuslaji, mutta sen kannat ovat taantuneet ja vaeltavat osakannat lähes hävinneet. Lajin suojelemiseksi on erityisesti Keski-Suomen koskikalastuskohteilla otettu käyttöön kalastus- ja välinerajoituksia, joiden tarkoituksena on vähentää kalastuspainetta ja –kuolleisuutta. Välinerajoitusten vaikutuksista kaloille aiheutuviin vaurioihin on kuitenkin niukasti tietoa. Tämän tutkimuksen tarkoituksena oli selvittää, miten koukun koko, väkänen ja tarttumiskohta vaikuttavat kalalle aiheutuneisiin kudosvaurioihin, verenvuodon määrään ja kalan kiinnipysymiseen. Aineisto kerättiin perinteisillä perhokalastusvälineillä. Käytössä oli kolmen koko…