Arctic charr in sympatry with burbot: ecological and evolutionary consequences

Knudsen, Rune; Amundsen, Per‐Arne; Klemetsen, Anders

doi:10.1007/s10750-009-0077-2

Cited by 23 publications

(23 citation statements)

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“…Such omnivorous feeding behavior is also common for charr in monomorphic populations, especially when there is strong competition for benthic resources in the littoral zone (Jørgensen and Klemetsen 1995; Knudsen et al. 2010; Eloranta et al. 2013).…”

Section: Discussionmentioning

confidence: 99%

Morphological divergence between three Arctic charr morphs – the significance of the deep‐water environment

Skoglund

Siwertsson

Amundsen

et al. 2015

Ecology and Evolution

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Morphological divergence was evident among three sympatric morphs of Arctic charr (Salvelinus alpinus (L.)) that are ecologically diverged along the shallow-, deep-water resource axis in a subarctic postglacial lake (Norway). The two deep-water (profundal) spawning morphs, a benthivore (PB-morph) and a piscivore (PP-morph), have evolved under identical abiotic conditions with constant low light and temperature levels in their deep-water habitat, and were morphologically most similar. However, they differed in important head traits (e.g., eye and mouth size) related to their different diet specializations. The small-sized PB-morph had a paedomorphic appearance with a blunt head shape, large eyes, and a deep body shape adapted to their profundal lifestyle feeding on submerged benthos from soft, deep-water sediments. The PP-morph had a robust head, large mouth with numerous teeth, and an elongated body shape strongly related to their piscivorous behavior. The littoral spawning omnivore morph (LO-morph) predominantly utilizes the shallow benthic–pelagic habitat and food resources. Compared to the deep-water morphs, the LO-morph had smaller head relative to body size. The LO-morph exhibited traits typical for both shallow-water benthic feeding (e.g., large body depths and small eyes) and planktivorous feeding in the pelagic habitat (e.g., streamlined body shape and small mouth). The development of morphological differences within the same deep-water habitat for the PB- and PP-morphs highlights the potential of biotic factors and ecological interactions to promote further divergence in the evolution of polymorphism in a tentative incipient speciation process. The diversity of deep-water charr in this study represents a novelty in the Arctic charr polymorphism as a truly deep-water piscivore morph has to our knowledge not been described elsewhere.

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Section: Discussionmentioning

confidence: 99%

Morphological divergence between three Arctic charr morphs – the significance of the deep‐water environment

Skoglund

Siwertsson

Amundsen

et al. 2015

Ecology and Evolution

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“…In these lakes, Arctic charr (Salvelinus alpinus L., hereafter charr) may act as a topdown controller and integrator of pelagic and littoral food-web compartments due to its exceptional phenotypic plasticity (Klemetsen et al, 2003a;Klemetsen, 2010). However, the potentially wide trophic niche of charr is often restricted because of interspecific resource competition with sympatric fish species such as European whitefish (Coregonus lavaretus L.) (Amundsen, Knudsen & Bryhni, 2010;Sandlund et al, 2010;Eloranta et al, 2011), burbot (Lota lota L.) (Knudsen, Amundsen & Klemetsen, 2010a) and, most commonly, brown trout (Salmo trutta L., hereafter trout; Nilsson, 1963;Langeland et al, 1991;Amundsen & Knudsen, 2009). Competition between charr and trout has been widely studied (e.g.…”

Section: Introductionmentioning

confidence: 99%

Niche segregation of coexisting Arctic charr (Salvelinus alpinus) and brown trout (Salmo trutta) constrains food web coupling in subarctic lakes

2012

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Summary 1. Generalist fish species are recognised as important couplers of benthic and pelagic food‐web compartments in lakes. However, interspecific niche segregation and individual specialisation may limit the potential for generalistic feeding behaviour. 2. We studied summer habitat use, stomach contents and stable isotopic compositions of the generalist feeder Arctic charr coexisting with its common resource competitor brown trout in five subarctic lakes in northern Norway to reveal population‐level and individual‐level niche plasticity. 3. Charr and trout showed partial niche segregation in all five lakes. Charr used all habitat types and a wide variety of invertebrate prey including zooplankton, whereas trout fed mainly on insects in the littoral zone. Hence, charr showed a higher potential to promote habitat and food‐web coupling compared to littoral‐dwelling trout. 4. The level of niche segregation between charr and trout and between pelagic‐caught and littoral‐caught charr depended on the prevailing patterns of interspecific and intraspecific resource competition. The two fish species had partially overlapping trophic niches in one lake where charr numerically dominated the fish community, whereas the most segregated niches occurred in lakes where trout were more abundant. 5. In general, pelagic‐caught charr had substantially narrower dietary and isotopic niches and relied less on littoral carbon sources compared to littoral‐caught conspecifics that included generalist as well as specialised benthivorous and planktivorous individuals. Despite the partially specialised planktivorous niche and thus reduced potential of pelagic‐dwelling charr to promote benthic–pelagic coupling, the isotopic compositions of both charr subpopulations suggested a significant reliance on both littoral and pelagic carbon sources in all five study lakes. 6. Our study demonstrates that both interspecific niche segregation between and individual trophic specialisation within generalist fish species can constrain food‐web coupling and alter energy mobilisation to top consumers in subarctic lakes. Nevertheless, pelagic and littoral habitats and food‐web compartments may still be highly integrated due to the potentially plastic foraging behaviour of top consumers.

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“…Piscivorous fish like large perch, pike (Esox lucius L., 1758) and burbot (Lota lota L., 1758) affect the habitat use of potential prey fish, such as small Arctic charr (Brabrand & Faafeng 1993;Langeland et al 1995). In deep lakes, Arctic charr may find a refugium in the profundal region, but will still face competition from other cold water species, including whitefish and burbot (Knudsen et al 2010). In shallow lakes, the cold water refugium in the profundal zone is missing, and Arctic charr must endure high summer temperatures, heavy predation and fierce competition.…”

Section: Introductionmentioning

confidence: 99%

Arctic charr (Salvelinus alpinus) squeezed in a complex fish community dominated by perch (Perca fluviatilis)

Sandlund

Haugerud²,

Rognerud³

et al. 2013

Fauna Norv.

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Sandlund OT, Haugerud E, Rognerud S and Borgstrøm R. 2013. Arctic charr (Salvelinus alpinus) squeezed in a complex fish community dominated by perch (Perca fluviatilis). Fauna norvegica 33: 1-11.In the complex fish community of Lake Skasen, southeastern Norway, the relative population density, habitat use and diet of Arctic charr, perch, roach and burbot was studied by a gill net survey during June-September 2010. A marked segregation in habitat use was observed, with Arctic charr and burbot captured in the profundal and deepest part of the pelagic habitat, and perch and roach captured in the littoral and upper part of the pelagic. Perch dominated the total catches, followed by roach. Arctic charr occurred in low numbers in the catches, and also had a low annual growth rate. Even in June, at low water temperatures, Arctic charr were confined to the profundal. Both Arctic charr, roach and perch fed on the same cladocerans, but all size groups of perch had fish as an important part of the diet. Analysis of stable carbon and nitrogen isotopes revealed a narrow trophic niche of Arctic charr, positioned at the extreme pelagic end of the carbon gradient relative to the other fish species. These had a wider span of δ 13 C signatures, but more positioned towards the littoral end of the carbon gradient. The low growth rate of Arctic charr, despite a low population density, indicates that food is a limiting resource for charr in this lake, probably due to a confinement to the profundal habitat as a result of competition and predator avoidance. Since all age-classes of Arctic charr seem to be enclosed in the profundal habitat, intraspecific competition and predation may be supplementary stressors resulting in low annual recruitment and low population density, as well as low individual growth rate, i.e. the population is squeezed. The narrow trophic niche of Arctic charr compared to perch, roach and burbot, revealed by stable isostope analysis, supports this conclusion.

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Arctic charr in sympatry with burbot: ecological and evolutionary consequences

Cited by 23 publications

References 65 publications

Morphological divergence between three Arctic charr morphs – the significance of the deep‐water environment

Morphological divergence between three Arctic charr morphs – the significance of the deep‐water environment

Niche segregation of coexisting Arctic charr (Salvelinus alpinus) and brown trout (Salmo trutta) constrains food web coupling in subarctic lakes

Arctic charr (Salvelinus alpinus) squeezed in a complex fish community dominated by perch (Perca fluviatilis)

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