Influence of the Submerged Aquatic Vegetation Landscape on Fish Larva Abundance

Submerged aquatic vegetation (SAV) creates functional habitats for aquatic organisms in both marine and freshwater ecosystems. By structuring habitats (fragmentation, patch size, complexity), SAV influences prey–predator interactions, population dynamics, community structure and ecosystem functioning. In freshwater ecosystems, the loss of SAV beds is occurring in many systems. Although many fish species occupy these habitats at some life history stage, the influence of the SAV landscape on their abundance has rarely been studied. We used yellow perch (Perca flavescens) as a biological model to evaluate the effect of the SAV landscape (characterized using satellite imagery) on the abundance of fish larvae in a large fluvial lake. After controlling for spatial autocorrelation among spawning grounds at a broad scale, we show that fish larvae are actively selecting SAV habitats after hatching. In habitats with low SAV biomass, the probability of observing perch larvae was approximately 20% and increased to nearly 100% in habitats with dense SAV (R² = 0.54). Our results also suggest that larvae use both new vegetation as well as SAV debris from the previous year that persisted through the winter.