Life history and large-scale habitat use of brown trout (Salmo trutta) and brook trout (Salvelinus fontinalis)
Over the years, several salmonid species have been widely spread and successfully introduced all over the world. In Sweden, introduced brook trout (Salvelinus fontinalis) has been successful in establishing a substantial number of new populations, a fact that has raised concerns about indigenous b...
| Autor principal: | |
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| Formato: | Otro |
| Lenguaje: | sueco Inglés |
| Publicado: |
2006
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| Materias: | |
| Acceso en línea: | https://stud.epsilon.slu.se/12430/ |
| _version_ | 1855572061818191872 |
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| author | Öhlund, Gunnar |
| author_browse | Öhlund, Gunnar |
| author_facet | Öhlund, Gunnar |
| author_sort | Öhlund, Gunnar |
| collection | Epsilon Archive for Student Projects |
| description | Over the years, several salmonid species have been widely spread and successfully introduced all over the world.
In Sweden, introduced brook trout (Salvelinus fontinalis) has been successful in establishing a substantial
number of new populations, a fact that has raised concerns about indigenous brown trout (Salmo trutta)
populations being outcompeted. The competitive relationships of introduced and native salmonids have received
much scientific attention, yet most studies have failed to reveal the specific mechanisms by which species
interact. A powerful way of dealing with interspecific competition is measuring of species-specific changes in
fitness over environmental and biotic gradients, an approach that requires accurate measurements of life
historical metrics. I compared the expression of life history traits in stream resident populations of 1) sympatric
brook trout and brown trout, 2) allopatric and sympatric brown trout. This information was complemented by a
survey on patterns of distribution and density of the two species on a larger geographical scale, covering various
environmental gradients. The comparisons of sympatric and allopatric brown trout indicated that brown trout life
history was effected by brook trout presence in terms of lower growth rate, delayed maturation and increased
apparent mortality. The life history of brook trout was clearly shorter than that of brown trout, with higher
growth rate, earlier maturation, higher fecundity and higher mortality. Data from the Swedish Electrofishing
Register indicates that brown trout in many cases can withstand competition from brook trout. It should be
remembered that very small streams where brook trout is most likely to be competitively dominant, probably are
underrepresented in the database. Still, it seems as though certain stream characteristics are required for
competitive exclusion of brown trout to occur. With stream size and productivity as the main features structuring
interactions between the two salmonids, combinations of other factors like temperature, level of structural
heterogeneity, amount of pools and deeper habitats and possibilities for female migration seem important on a
spatially smaller scale. I suggest that behavioral differences in combination with the above factors, might
gradually decrease the ability of brown trout to withstand competition from brook trout as stream-size and/or
productivity declines |
| format | Otro |
| id | RepoSLU12430 |
| institution | Swedish University of Agricultural Sciences |
| language | Swedish Inglés |
| publishDate | 2006 |
| publishDateSort | 2006 |
| record_format | eprints |
| spelling | RepoSLU124302017-10-30T09:41:13Z https://stud.epsilon.slu.se/12430/ Life history and large-scale habitat use of brown trout (Salmo trutta) and brook trout (Salvelinus fontinalis) Öhlund, Gunnar Fisheries and aquaculture - General aspects Over the years, several salmonid species have been widely spread and successfully introduced all over the world. In Sweden, introduced brook trout (Salvelinus fontinalis) has been successful in establishing a substantial number of new populations, a fact that has raised concerns about indigenous brown trout (Salmo trutta) populations being outcompeted. The competitive relationships of introduced and native salmonids have received much scientific attention, yet most studies have failed to reveal the specific mechanisms by which species interact. A powerful way of dealing with interspecific competition is measuring of species-specific changes in fitness over environmental and biotic gradients, an approach that requires accurate measurements of life historical metrics. I compared the expression of life history traits in stream resident populations of 1) sympatric brook trout and brown trout, 2) allopatric and sympatric brown trout. This information was complemented by a survey on patterns of distribution and density of the two species on a larger geographical scale, covering various environmental gradients. The comparisons of sympatric and allopatric brown trout indicated that brown trout life history was effected by brook trout presence in terms of lower growth rate, delayed maturation and increased apparent mortality. The life history of brook trout was clearly shorter than that of brown trout, with higher growth rate, earlier maturation, higher fecundity and higher mortality. Data from the Swedish Electrofishing Register indicates that brown trout in many cases can withstand competition from brook trout. It should be remembered that very small streams where brook trout is most likely to be competitively dominant, probably are underrepresented in the database. Still, it seems as though certain stream characteristics are required for competitive exclusion of brown trout to occur. With stream size and productivity as the main features structuring interactions between the two salmonids, combinations of other factors like temperature, level of structural heterogeneity, amount of pools and deeper habitats and possibilities for female migration seem important on a spatially smaller scale. I suggest that behavioral differences in combination with the above factors, might gradually decrease the ability of brown trout to withstand competition from brook trout as stream-size and/or productivity declines Genom åren har laxartade fiskarter spridits och etablerats på många håll världen över. I Sverige har bäckröding (Salvelinus fontinalis) etablerat ett betydande antal nya populationer, något som framkallat oro över eventuella effekter på inhemska populationer av öring (Salmo trutta). Konkurrensförhållanden mellan introducerade och inhemska laxartade fiskarter har erhållit mycket vetenskaplig uppmärksamhet. Trots det har det stora flertalet studier misslyckats med att avslöja de specifika mekanismer genom vilka arterna interagerar. Ett kraftfullt sätt att behandla mellanartskonkurrens är att mäta fitness och dess artspecifika variation över abiotiska och biologiska gradienter, ett tillvägagångssätt som kräver noggranna mått på livshistoriska karaktärer. Jag jämförde livshistoria hos strömstationära populationer av 1) bäckröding och öring i sympatri 2) öring i allopatri och sympatri. Som komplement användes data från det Svenska elfiskeregistret där tätheter och utbredning av de två arterna jämfördes i en rumsligt större skala, över olika abiotiska gradienter. Jämförelsen mellan allopatriska och sympatriska öringpopulationer indikerade att öringens livshistoria påverkades av bäckrödingens närvaro, detta i form av lägre tillväxt, senarelagd könsmognad samt högre mortalitet och/eller vandringsbenägenhet. Bäckrödingens livshistoria var tydligt kortare än öringens, med högre tillväxt, kortare generationstid, högre fekunditet samt högre mortalitet. Data från det nationella elfiskeregisteret indikerar att öring i många fall klarar av att utsättas för konkurrens från bäckröding. Det bör påpekas att de mycket små vattendrag där sannolikheten för att bäckröding ska vara konkurrensmässigt dominant är störst, med stor sannolikhet är underrepresenterade i elfiskeregistret. Resultaten indikerar ändå att det krävs vissa specifika habitatkaraktärer för öring ska konkureras ut av bäckröding. Medan vattendragsstorlek och produktivitet är de huvudfaktorer som strukturerar interaktionen mellan de två arterna, verkar habitatkaraktärer som temperatur, strukturell heterogenitet, tillgång av höljor och djupare områden samt möjligheter till habitatskiften vara viktiga i den mindre skalan. Jag föreslår att beteendemässiga skillnader i kombination med ovanstående faktorer kan leda till en succesiv försämring av öringens förmåga att klara av konkurrens från bäckröding när vattendragsstorlek och/eller produktivitet minskar. 2006-12-20 Other NonPeerReviewed application/pdf sv https://stud.epsilon.slu.se/12430/1/ohlund_g_171030.pdf Öhlund, Gunnar, 2002. Life history and large-scale habitat use of brown trout (Salmo trutta) and brook trout (Salvelinus fontinalis) : implications for distributional patterns in small lotic systems. UNSPECIFIED, Umeå. Umeå: (NL, NJ) > Dept. Of Aquatic Resources <https://stud.epsilon.slu.se/view/divisions/OID-135.html> urn:nbn:se:slu:epsilon-s-8396 eng |
| spellingShingle | Fisheries and aquaculture - General aspects Öhlund, Gunnar Life history and large-scale habitat use of brown trout (Salmo trutta) and brook trout (Salvelinus fontinalis) |
| title | Life history and large-scale habitat use of brown trout (Salmo trutta) and brook trout (Salvelinus fontinalis) |
| title_full | Life history and large-scale habitat use of brown trout (Salmo trutta) and brook trout (Salvelinus fontinalis) |
| title_fullStr | Life history and large-scale habitat use of brown trout (Salmo trutta) and brook trout (Salvelinus fontinalis) |
| title_full_unstemmed | Life history and large-scale habitat use of brown trout (Salmo trutta) and brook trout (Salvelinus fontinalis) |
| title_short | Life history and large-scale habitat use of brown trout (Salmo trutta) and brook trout (Salvelinus fontinalis) |
| title_sort | life history and large-scale habitat use of brown trout (salmo trutta) and brook trout (salvelinus fontinalis) |
| topic | Fisheries and aquaculture - General aspects |
| url | https://stud.epsilon.slu.se/12430/ https://stud.epsilon.slu.se/12430/ |