Habitat selectivity of substrate-spawning fish: modelling requirements for the Eurasian perch Perca fluviatilis

• Substrate spawning fish are believed to be selective in their choice of spawning habitat,yet few studies have shown the relative importance of different characteristics in terms of habitatquality. We used an extensive and detailed dataset to identify the factors that govern both large-scale(1 000 to 100 000 m) and local-scale (10 to 100 m) selection by a substrate-spawning fish, the Eurasian perchPerca fluviatilis L. Distribution of spawning habitat was strongly dependent on habitat characteristicsdefined by substrate, wave exposure, temperature and depth. The most important predictor was thetype of spawning substrate, which generally consisted of different types of vegetation. Substratesproviding rigidity and structural complexity were preferred, despite abundant presence of other substratetypes. Shallow depth and sheltered areas were also selected habitat characteristics. Theresponse to temperature was scale-dependent, with a stronger selection expressed at the local scale.The specific selectivity suggests that spawning patterns can be successfully modelled with sufficientdetail using only a few fundamental environmental variables. Wave exposure and depth are readilyavailable for large-scale spatial predictions, while temperature and substrate require further developmentin most coastal areas. The high specificity of the characteristics determining habitat qualitysuggests that it should be possible to apply this modelling approach for identification and conservationof spawning habitats of Eurasian perch and other substrate-spawning fishes in coastal waters.

Nyckelord

Habitat modelling

Nursery areas

Large-scale maps

Macrophytes

Behaviour; Oviposition

Generalised additive model

GAM

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