Spawning site selection of brown trout in habitat restored streams
During the timber floating era, most of Sweden’s watercourses were altered. This decreased the amount of available spawning habitats for salmonids, and hence had a negative effect on the riverine brown trout (Salmo trutta) populations. Reconstruction of spawning grounds is today a common measure in...
| Autor principal: | |
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| Formato: | Second cycle, A2E |
| Lenguaje: | sueco Inglés |
| Publicado: |
2012
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| Acceso en línea: | https://stud.epsilon.slu.se/4289/ |
| _version_ | 1855570658936750080 |
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| author | Svensson, Jonas |
| author_browse | Svensson, Jonas |
| author_facet | Svensson, Jonas |
| author_sort | Svensson, Jonas |
| collection | Epsilon Archive for Student Projects |
| description | During the timber floating era, most of Sweden’s watercourses were altered. This decreased the amount of available spawning habitats for salmonids, and hence had a negative effect on the riverine brown trout (Salmo trutta) populations. Reconstruction of spawning grounds is today a common measure in restoration of altered streams in Sweden. However, very little evaluation of the effectiveness of these reconstructed spawning grounds exists. Hence, today we lack knowledge on how to further improve the construction of spawning habitats.
In this study, conducted in boreal streams in northern Sweden, I have investigated the influence of several variables believed to have importance in spawning habitat selection for brown trout. I have investigated variables at two different scales, the patch scale (the microhabitat where the fish are spawning) and the bed scale (the macrohabitat that surrounds the spawning bed). My results suggest that the percentage of fines within the spawning substrate is an important predictor on probability of spawning at the patch scale. I also report moderate influence of water velocity, area and depth on probability of spawning at the patch scale. Distance to shore were found to have some influence on the selection of spawning bed by trout, while distance to cover for adult spawners, as well as distance to, and size of, nursery habitat were found to have low importance.
To apply these findings for fish and wildlife managers I point out that raking and cleaning of gravel, and the placement of spawning beds further away from shore may be important measures to enhance the probability of spawning in reconstructed spawning habitats.
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| format | Second cycle, A2E |
| id | RepoSLU4289 |
| institution | Swedish University of Agricultural Sciences |
| language | Swedish Inglés |
| publishDate | 2012 |
| publishDateSort | 2012 |
| record_format | eprints |
| spelling | RepoSLU42892012-10-12T13:24:50Z https://stud.epsilon.slu.se/4289/ Spawning site selection of brown trout in habitat restored streams Svensson, Jonas Aquatic ecology During the timber floating era, most of Sweden’s watercourses were altered. This decreased the amount of available spawning habitats for salmonids, and hence had a negative effect on the riverine brown trout (Salmo trutta) populations. Reconstruction of spawning grounds is today a common measure in restoration of altered streams in Sweden. However, very little evaluation of the effectiveness of these reconstructed spawning grounds exists. Hence, today we lack knowledge on how to further improve the construction of spawning habitats. In this study, conducted in boreal streams in northern Sweden, I have investigated the influence of several variables believed to have importance in spawning habitat selection for brown trout. I have investigated variables at two different scales, the patch scale (the microhabitat where the fish are spawning) and the bed scale (the macrohabitat that surrounds the spawning bed). My results suggest that the percentage of fines within the spawning substrate is an important predictor on probability of spawning at the patch scale. I also report moderate influence of water velocity, area and depth on probability of spawning at the patch scale. Distance to shore were found to have some influence on the selection of spawning bed by trout, while distance to cover for adult spawners, as well as distance to, and size of, nursery habitat were found to have low importance. To apply these findings for fish and wildlife managers I point out that raking and cleaning of gravel, and the placement of spawning beds further away from shore may be important measures to enhance the probability of spawning in reconstructed spawning habitats. De flesta av Sveriges vattendrag blev förändrade under flottningsepoken. Detta minskade mängden tillgängliga lekområden för salmonider och det hade därmed en negativ effekt på öringspopulationerna (Salmo trutta) i vattendragen. Idag är återuppbyggnad av lekbottnar en vanlig del i restaureringen av påverkade svenska vattendrag. Uppföljningar av uppbyggda lekbottnar har utförts i begränsad omfattning och därför saknar vi idag kunskapen för ytterligare förbättring av lekbottenrestaureringen. I denna studie, utförd i boreala vattendrag i norra Sverige, har jag undersökt påverkan från olika variabler som tros vara viktiga i valet av lekområde för öring. Jag har undersökt variabler i två olika skalor, lekbåsskalan (mikrohabitatet där fisken leker) och lekbottenskalan (makrohabitatet som omger en lekbotten). Resultatet visade att procentuellt inslag av finpartiklar i substratet är en indikation för sannolikhet till lek i något bås. Jag fann även att vattenhastighet, båsets area och djup hade moderat inverkan på sannolikheten till lek i något bås. Avstånd till närmsta strand visade sig ha viss påverkan på lekbottenselektion hos öring, medan avstånd till skydd för lekfisk likväl som avstånd, och area, av yngelhabitat visade sig ha liten påverkan. För att applicera detta för fiskförvaltare vill jag påpeka att krattning och städning av lekgrus och placering av lekbottnar längre från stranden i bäcken kan vara viktiga åtgärder för att öka sannolikheten till lek i ett rekonstruerat lekhabitat. 2012-06-12 Second cycle, A2E NonPeerReviewed application/pdf sv https://stud.epsilon.slu.se/4289/1/Svensson_J_120612.pdf Svensson, Jonas, 2012. Spawning site selection of brown trout in habitat restored streams. Second cycle, A2E. Umeå: (S) > Dept. of Wildlife, Fish and Environmental Studies <https://stud.epsilon.slu.se/view/divisions/OID-251.html> urn:nbn:se:slu:epsilon-s-1203 eng |
| spellingShingle | Aquatic ecology Svensson, Jonas Spawning site selection of brown trout in habitat restored streams |
| title | Spawning site selection of brown trout in habitat restored streams |
| title_full | Spawning site selection of brown trout in habitat restored streams |
| title_fullStr | Spawning site selection of brown trout in habitat restored streams |
| title_full_unstemmed | Spawning site selection of brown trout in habitat restored streams |
| title_short | Spawning site selection of brown trout in habitat restored streams |
| title_sort | spawning site selection of brown trout in habitat restored streams |
| topic | Aquatic ecology |
| url | https://stud.epsilon.slu.se/4289/ https://stud.epsilon.slu.se/4289/ |