Nauka Przyroda Technologie

Abstract. Jeziorsko, a dam reservoir, is a multi-purpose detention lake which serves various purposes, including significant economic (fishing) and recreational (angling) ones. It is the second largest (after Włocławek Lagoon) dammed reservoir in Poland with the surface area of 3100 hectares. Catchment, biological and breeding conditions make the lake substantially potent in terms of fish production. Fair use of these assets for fish farming has been the fundamental objective of scheduled and completed tasks. An assessment of potentiality and capacity in natural resources management has been made on the basis of fish harvesting and stocking analysis of nearly 20 years (1988-2006) of Jeziorsko exploitation for fishery purposes. In that time, the reservoir was constantly exploited by anglers due to its location and recreational value. Unfortunately, as a result of unfavorable decisions made by the user, practically no records of amateur fishing were kept. This mistake made it impossible to fully discern the actual, natural fishing efficiency and a complex evaluation of the ichthyobiotic community in Jeziorsko.