engleski

Characteristics of the stone crayfish (Austropotamobius torrentium Schrank) population from the Mrzlak Stream on the Medvednica Mountain, Croatia

The stone crayfish Austropotamobius torrentium (Schrank, 1803) is one of four native European crayfish species living in Croatian freshwaters. This species lives mostly in running waters at higher altitudes. The Mrzlak Stream belongs to the Sava River basin, and is located at southern slopes of the Medvednica Mountain, northwest Croatia. Stone crayfish were caught by hand and hand made baited traps that were set in the stream monthly, from April 2005 until May 2006. During the sampling period we caught 414 crayfish of which 224 males and 190 females. For each trapped crayfish sex, reproductive and molting stage as well as weight and 12 morphometrical characteristics were recorded. Crayfish were individually marked by piercing holes into the uropods and/or telson and then released. Year cycle and size structure of the stone crayfish population in the Mrzlak Stream were described. Population size was estimated by mark-recapture methods (Schnabel method, Schumacher and Eschmeyer method). Positive correlation was found between weight and length of crayfish. Males and females differed statistically significant in weight and claw size. As the Mrzlak Stream is located in the area of the Nature Park Medvednica results obtained in this research would be used in protection management plans.

stone crayfish; Austropotamobius torrentium; population size; morphometry

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