Surprising but Crucial Food Source for Arctic Charr in a Remote Lake

Jim Crocker
27th May, 2024

Surprising but Crucial Food Source for Arctic Charr in a Remote Lake

Image Source: Natural Science News, 2024

Key Findings

  • The study by the Norwegian Institute for Nature Research (NINA) discovered the mysid species Mysis segerstralei in Lake Pulmankijärvi, a rare find in Western European freshwater lakes
  • Mysis segerstralei was found to be a significant prey item for Arctic charr in Lake Vårfluesjøen, highlighting its role in the lake's food web
  • The presence of Mysis segerstralei in Arctic charr diets underscores the species' adaptability and ecological importance in Arctic lake ecosystems
The study conducted by the Norwegian Institute for Nature Research (NINA)[1] sheds light on the unexpected presence of the mysid species Mysis segerstralei in Lake Pulmankijärvi, situated at the border between Northeastern Norway and Finland. This discovery is particularly intriguing given that M. segerstralei is typically found in marine and brackish waters around Svalbard, and has seldom been documented in freshwater lakes in Western Europe. Mysis segerstralei's broad geographic distribution and habitat versatility, including its ability to thrive in various salinity conditions, have been previously noted[2]. This species shows high genetic diversity and minimal phylogeographic structuring across the Arctic, indicating its capability for late-glacial dispersal among coastal and lake populations from Alaska, Siberia, and Northern Europe. This adaptability is further evidenced by a strongly divergent refugial lineage identified in Beringia[2]. The recent study focused on the diet of Arctic charr (Salvelinus alpinus) in Lake Vårfluesjøen, a low-productive, High Arctic lake characterized by low water temperatures, long-term ice cover, and limited nutrient levels. Arctic charr, being the only freshwater fish species in Svalbard, primarily consume chironomids due to the scarcity of other food sources. However, the unexpected presence of M. segerstralei in the stomach contents of Arctic charr sampled from profundal, littoral, and pelagic habitats in Lake Vårfluesjøen highlights the significant role of mysids in the lake's food web. This finding aligns with earlier research on Arctic charr's dietary flexibility and trophic roles across different environments[3]. Arctic charr exhibit remarkable adaptability to varying abiotic and biotic changes, ranging from lakes and rivers in the High Arctic to deep, multi-species lakes outside the polar region. Their ability to switch trophic roles and adjust their niche use and life-history traits, such as body size and longevity, is crucial for maintaining their populations in diverse and changing ecosystems[3]. The study's methodology involved several surveys spanning decades, examining the stomach contents of Arctic charr in more than 30 Svalbard lakes. The consistent presence of M. segerstralei as a prey item in Lake Vårfluesjøen underscores the mysid's importance, even in such a low-productive environment. This discovery not only expands our understanding of M. segerstralei's distribution but also emphasizes the ecological significance of mysids in Arctic lake systems. Moreover, the study's findings contribute to the broader understanding of food-web dynamics in oligotrophic high-latitude lakes. Previous research has shown that the energy flow and prey preference of top predators, like Arctic charr, are crucial for the structure and function of aquatic ecosystems[4]. In lakes with varying sizes and fish species richness, Arctic charr have been observed to shift their reliance on littoral versus pelagic energy sources and adjust their trophic positions accordingly. This adaptability is vital for maintaining food-web stability and species diversity[4]. In conclusion, the discovery of Mysis segerstralei in Lake Pulmankijärvi and its role as a significant prey item for Arctic charr in Lake Vårfluesjøen highlights the species' adaptability and ecological importance. This study, supported by earlier findings on the phylogeographic structures of mysid species[2] and the dietary flexibility of Arctic charr[3], underscores the complex interactions and energy flow in Arctic lake ecosystems. The research conducted by NINA provides valuable insights into the resilience and adaptability of aquatic species in response to environmental changes, contributing to our broader understanding of Arctic biodiversity and ecosystem dynamics.

EcologyAnimal ScienceMarine Biology

References

Main Study

1) Mysis segerstralei, an unexpected but important prey for resident Arctic charr (Salvelinus alpinus) in a Svalbard lake

Published 26th May, 2024

https://doi.org/10.1007/s00300-024-03261-w

Related Studies

2) Phylogeographic analyses of a circumarctic coastal and a boreal lacustrine mysid crustacean, and evidence of fast postglacial mtDNA rates.

Journal: Molecular ecology, Issue: Vol 15, Issue 11, Oct 2006

3) Natural resilience in Arctic charr Salvelinus alpinus: life history, spatial and dietary alterations along gradients of interspecific interactions.

https://doi.org/10.1111/jfb.12321

4) Lake size and fish diversity determine resource use and trophic position of a top predator in high-latitude lakes.

https://doi.org/10.1002/ece3.1464


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