Fish communities in shallow lakes

While there is an intuitive understanding of what “shallow lake” means, it is more difficult to provide a precise definition of the term. For our purposes, we could include in this category lakes with a depth not exceeding 10 m and with no permanent stratification of the water column (Lévêque & Quensière, 1988). Shallow lakes are thus lakes in which the coastal area and bankside vegetation play an important role in the function of the system, in contrast to deep lakes where the pelagic zone is particularly well-developed.Shallow lakes generally occupy depressions in areas with moderate reliefs. Despite their diversity, they all share certain characteristics:• There is significant development of grassy zones that can occupy large surfaces.• Macrophytes develop on the shoals and produce a large amount of organic matter;• Fluctuations in the water balance (summation of water inputs and outputs) manifest as large fluctuations in water level and surface, owing to the basin’s lack of relief.• The water balance depends greatly on the local climate as well as the climate of the basin feeding the tributaries, and on the shape of the lake basin;• The absence of permanent thermal stratification favours the rapid recycling of nutritive elements as well as the development of benthic fauna that helps increase the productivity of these physical systems