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We studied life cycle of stone crayfish for 18 months in three streams on Medvednica Mountain, located above city of Zagreb. Sampling of animals was carried out with baited traps twice a month and various physiological functions were recorded. Sex ratio of trapped crayfish was 1:1, but it fluctuated during the year. Animals were active from early spring until the beginning of November when their activities significantly decreased. In this period we noticed three peaks of higher activity. The first one after winter starvation in March, the second one after egg hatching (June/July) and the third one during mating period (end of September -beginning of November). The maximal recorded weight for female was 38 g while the heaviest male was 55 g. The longest female was 9.28 cm and male 10.30 cm. Development of glair glands started from the end of July, mating occurred at the end of October and the juveniles hatched until mid-June. Freshly moulted animals were found from mid-May until mid-October. Main injuries were claw and limb loss. We noticed the presence of burn spot disease and Branchiobdella parasita Henle within studied populations. Correlation with five different physico-chemical parameters of water showed that animals' activity is positively correlated to water temperature, conductivity, pH and hardness and negatively to oxygen concentration.

The aim of our research was to gather information about the reproduction cycle of Austopotamobius torrentium in Croatia. The research was conducted between October 1998 and April 2000 in streams on the Medvednica Mountain (north-west Croatia). We caught 767 females, of which 92 (11.99%) were berried. Berried females were captured from the beginning of November until mid June of the following year. Total length (from the tip of the rostrum to the end of telson) of the smallest female with pleopodal eggs was 5.40 cm, while the longest was 8.70 cm. Diameter of pleopodal eggs varied from 0.24 cm to 0.34 cm (mean ± SD = 0.28 ± 0.02) and their number per female from 1 to 104. Correlations between female size (total length and weight), number of pleopodal eggs and egg diameter were done. We found positive correlation between female length and number of eggs (r = 0.46) and between female length and egg diameter (r = 0.29), as well as between female weight and egg number (r = 0.50) and female weight and egg diameter (r = 0.30). Weak positive correlation was recorded between number of eggs and their diameter (r = 0.06).Key-words: stone crayfish, Austropotamobius torrentium, fecundity, egg size. RELATION ENTRE LA TAILLE DES FEMELLES ET LEURS OEUFS CHEZ L'ÉCREVISSE AUSTROPOTAMOBIUS TORRENTIUM RÉSUMÉ