Linda Puncule explored the factors shaping fish communities in temperate lakes in her doctoral thesis

The thesis “Food web interactions, habitat complexity, and human pressure as key determinants of fish community dynamics in temperate lakes” was supervised by Associate Professor Priit Zingel and Associate Professor Matiss Zagars (University of Latvia), and the opponent was Professor Torben Linding Lauridsen (Aarhus University).

In her doctoral research, Linda Puncule studied fish community dynamics and food web functioning in northern temperate lakes in Estonia and Latvia, focusing in particular on early life stages of Fish, larvae and juveniles, which serve as important bioindicators of ecosystem status. The results show that recruitment success largely depends on zooplankton biomass and community structure, which determine the feeding and growth of young fish and establish a clear link between lake productivity and fish population development potential.

The study highlights the importance of habitat diversity. Vegetation-rich areas, especially those dominated by floating-leaved plants, provide shelter for fish and help stabilize food webs, thereby increasing ecosystem resilience to environmental disturbances. At the same time, the thesis points to the negative impacts of human activities, particularly overfishing and illegal fishing, which can disrupt the entire lake food web and degrade water quality. The loss of large predatory fish due to overfishing or poaching triggers a cascade effect, leading to an overabundance of planktivorous fish and a decline in water quality.

The thesis concludes that maintaining the good ecological status of lakes requires integrating habitat protection with effective fisheries management to preserve the natural balance of ecosystems.

The doctoral thesis is available in the digital archive of the Estonian University of Life Sciences EMÜ DSpace.link opens in new page