Table S1: Selected species and age classes for the analysis of spatial effect and cohort effect. For

the spatial effect, we evaluated the association between densities of individuals occurring at

neighbouring sites (especially fish juveniles). For the cohort effect, we evaluated the association

between the densities of juveniles and older individuals with a one-year time lag (only for fish).

Data sets Spatial effect Cohort effect

Stream age-0 Salmo trutta

age-0 vs. age-1Salmo trutta

River

age-0 Alburnus alburnusSqualius cephalusRutilus rutilus Gobio gobioChondrostoma nasusBarbatula barbatula

age-0 vs. age-1+

Alburnus alburnusAlburnoides bipunctatusBarbatula barbatulaBarbus barbusBlicca bjœrknaChondrostoma nasusGobio gobio Lepomis gibbosus

age-0 vs. age-1+

Leuciscus leuciscusPerca fluviatilis Phoxinus phoxinusPseudorasbora parvaRhodeus amarusRutilus rutilusScardinius erythrophthalmusSqualius cephalus

Estuary

age-0Alosa alosaAlosa fallaxAnguilla anguillaLiza ramadaPomatoschistus minutusSyngnathus rostellatus

all ageArgyrosomus regiusCrangon crangon Dicentrarchus labraxEngraulis encrasicolusGasterosteus aculeatusSprattus sprattus

age-0 vs. age-1+

Anguilla anguillaLiza ramadaPomatoschistus minutusSyngnathus rostellatus

Marine all ageAlloteuthisArgentina sphyraenaArnoglossus imperialisArnoglossus laternaCallionymus lyraCallionymus maculatusCancer pagurusCapros aperChelidonichthys cuculusConger congerEledone cirrhosaEngraulis encrasicolusGadiculus argenteus

all ageLoligo forbesiLophius piscatoriusMerluccius merlucciusMicromesistius poutassouMicrochirus variegatusPhycis blennoidesSardina pilchardusScomber scombrusScyliorhinus caniculaSepia elegansSepiolaTodaropsis eblanaeTrachurus trachurus

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Illex coindetiiLepidorhombus whiffiagonisLeucoraja naevus

Trisopterus luscusTrisopterus minutusZeus faber

Fig. S1: Spatial distribution of the 32 dominant species of the Marine dataset. For each species,

purple and orange dots correspond to the northern and southern zones, respectively. Complete

species names are provided in Table S1.

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