Accuracy of Assessing the Abundance of Fish Generations under Conditions of Incomplete Initial Information

Dynamic phase portrait: New possibilities of detecting changes in populations

“…3). The further study of dynamics of separate generations of zander revealed that all generations born in 1993-1996 were numerous, and generations born in 1997-1999 were not (Tereshchenko & Zuyanova, 2006). In other words, by the late 1990s, in the lake, the consequences of overpopulation of zander were observed.…”

“…3. Dynamic phase portrait of zander catch in Lake Vozhe (according to Tereshchenko & Zuyanova, 2006): the numbers on the curve are years of population being in the state indicated by the point on the curve Changes in population under the effect of intense sport fishing. As an example, we shall consider the population of grayling (Thymallus thymallus) in the upper stream of the Vym River in the conditions of influence of poorly-controlled non-commercial fishing.…”

“…During the process of growth of a population, the moment occurs, when the mechanisms of density regulation are activated. The possibility of assessment of a density at which the mortality was higher than birth rate and emigration of individuals from the regions with high density was observed is demonstrated on the example of zander (Sander lucioperca) introduced into Lake Vozhe (Tereshchenko & Zuyanova, 2006).…”