Water Transparency Drives Intra-Population Divergence in Eurasian Perch (Perca fluviatilis)

Abstract

Trait combinations that lead to a higher efficiency in resource utilization are important drivers of divergent natural selection and adaptive radiation. However, variation in environmental features might constrain foraging in complex ways and therefore impede the exploitation of critical resources. We tested the effect of water transparency on intra-population divergence in morphology of Eurasian perch (Perca fluviatilis) across seven lakes in central Sweden. Morphological divergence between near-shore littoral and open-water pelagic perch substantially increased with increasing water transparency. Reliance on littoral resources increased strongly with increasing water transparency in littoral populations, whereas littoral reliance was not affected by water transparency in pelagic populations. Despite the similar reliance on pelagic resources in pelagic populations along the water transparency gradient, the utilization of particular pelagic prey items differed with variation in water transparency in pelagic populations. Pelagic perch utilized cladocerans in lakes with high water transparency and copepods in lakes with low water transparency. We suggest that under impaired visual conditions low utilization of littoral resources by littoral perch and utilization of evasive copepods by pelagic perch may lead to changes in morphology. Our findings indicate that visual conditions can affect population divergence in predator populations through their effects on resource utilization.

Morphological variation among populations of Hemigrammus coeruleus (Characiformes: Characidae) in a Negro River tributary, Brazilian Amazon

“…However, it might play an important role in visually oriented predator avoidance and foraging behaviour (Rodríguez, Lewis, 1997), since transparency drops to only a few centimetres (compared to ≥ 1.4 m in the sediment-free black-water rivers). Evidence for morphological divergences due primarily to water transparency have been reported in other studies, such as Bartels et al (2012) for populations of Perca fluviatilis.…”

Genetic and morphological divergence along the littoral-pelagic axis in two common and sympatric fishes: perch,Perca fluviatilis(Percidae) and roach,Rutilus rutilus(Cyprinidae)

“…Although individuals from different habitats showed overlapping morphology, indicating the existence of incomplete assortative mating or morphs that are not confined to a single habitat, there were significant differences in morphology across the littoral–pelagic axis for both species in all lakes, except DN. Previous work has suggested that morphological differentiation of perch increases with water transparency (Bartels et al ., ). However, the abiotic features, including water transparency (Secchi depth), are very similar across all lakes, providing no strong evidence to explain the lack of divergence in DN.…”

A way forward with eco evo devo: an extended theory of resource polymorphism with postglacial fishes as model systems

“…specific ecological factors) that structure local selection regimes (e.g. MacColl, ), they show that a range of biotic and abiotic agents of selection (and their interactions) are associated with phenotypic divergence (Robinson & Wilson, ; Smith & Skúlason, ; Robinson & Schluter, ; Knudsen, Amundsen, & Klemetsen, ; Siwertsson et al ., ; Bartels et al ., ; Keller & Seehausen, ; Woods et al ., ; Franklin et al ., ). Biotic factors include low levels of interspecific but high levels of intraspecific competition, as well as interactions with prey, predators and parasites.…”