Determination of Variations in Fish Growth during Reservoir Ontogeny: a Case Study of the Mirror Carp Population in Gelingüllü Dam Lake (Yozgat, Turkey)


Abstract: Reservoirs are unstable environments as a very rapid change from a riverine to lacustrine environment occurs in terms of hydrology, climatology and ecology. These changes have a very significant influence on the growth and reproduction of fish populations. In this study, the effects of different phases of reservoir ontogeny on fish growth in Gelingüllü Dam Lake, a typical Central Anatolian reservoir, were monitored. The growth of mirror carp introduced into Gelingüllü Dam Lake was studied both during an initial phase, from 1995 to 1996, and during a later pre-depression phase, from 1998 to 2000. The growth parameters were compared in order to determine the ontogeny of the reservoir in terms of fish growth. According to the results, mean length and weight for 18-month-old mirror carp in 1995 were respectively 37.7 cm and 1550 g. The same parameters decreased to 23.6 cm and 374 g in 1999. Over 5 years, a significant decrease in both the length and weight of mirror carp was observed. These decreases are probably due to the gradual change from the impoundment phase to the depression phase in the reservoir.

Keywords: Mirror carp, reservoir ontogeny, Gelingüllü dam lake

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