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Trophic niche of arctic charr (Salvelinus alpinus) coexisting with lake trout (Salvelinus namaycush) and european whitefish (Coregonus lavaretus) in two divergent subarctic lakes
| Content Provider | Semantic Scholar |
|---|---|
| Author | Nieminen, Petri |
| Copyright Year | 2012 |
| Abstract | Introductions and invasions of new fish species can pose a threat to Arctic charr (Salvelinus alpinus ) causing population declines and even local extinc tio s through interspecific competition. In this thesis, the diet , main energy flow pathway and growth of Arctic charr and introduced alien species, lake tro ut (Salvelinus namaycush ), were studied in large and deep Lake Inarijärvi. Similarly, the d iet, main energy flow pathway and growth of Arctic charr and introduced European whit efish (Coregonus lavaretus ) were studied in small and shallow Lake Skaidijärvi. Stom ach contents and stable isotope analyses revealed a dietary and isotopic niche over lap between Arctic charr and lake trout in Lake Inarijärvi, indicating that the species are competing for the same food resources. Both species exhibited piscivory and large individu als (> 280 mm) had almost exlusively been feeding on small European whitefish and vendac e (Coregonus albula ). Small individuals (< 280 mm) of Arctic charr consumed mai nly zoobenthos and nine-spined sticklebacks. Despite the apparent resource competi tion, abundant prey fish populations may be able to support the coexistence of Arctic ch arr and lake trout in Lake Inarijärvi. In Lake Skaidijärvi, the results of stomach contents a nd stable isotope analysis showed a distinct resource partitioning, as Arctic charr for aged on three-spined sticklebacks (Gasterosteus aculeatus ), Gammarus sp. and trichopterans, while European whitefish consumed zooplankton and chironomids. This niche se gregation is likely to be a result of interspecific competition between the species. The energy mobilization through littoral and pelagic food webs up to fish seemed to differ betwe n the study lakes. A probable reason for this was the size difference between the lakes. In Lake Inarijärvi, lake trout (> 280 mm) and small Arctic charr (< 280 mm) gained most of th eir energy via the littoral food web, whereas large Arctic charr (> 280 mm) relied slight ly more on pelagic production. In Lake Skaidijärvi, both Arctic charr and European whitefi sh relied clearly on the littoral production. Introduced fish species grew faster tha n the native Arctic charr in both study lakes, indicating that they might be competing more eff ctively on the limited resources. However, the faster growth rate of lake trout in La ke Inarijärvi may be partly due to the aquacultural origin of the species. Introductions o f n n-native species to Arctic charr lakes should be always considered with caution as they ma y increase the competitive interactions and thereby be a risk to Arctic charr populations. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://jyx.jyu.fi/bitstream/handle/123456789/38148/URN:NBN:fi:jyu-201207052007.pdf?isAllowed=y&sequence=1 |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
