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FECUNDITY OF INDIGENOUS STONE CRAYFISH POPULATIONS: IMPLICATIONS FOR CRAYFISH CONSERVATION IN AUSTRIA AND CROATIA

The stone crayfish (Austropotamobius torrentium) is the smallest species in Astacidae family, indigenous to the Central and South-eastern Europe. It is threatened mainly due to various anthropogenic impacts upon its habitat, and as little is known about its ecology, biology and life cycle, one of the aims of the collaborative Austro-Croatian project was to gather information about this species reproductive cycle. Research was conducted during spring and summer 2006 and 2007 at two localities in Austria and four localities in Croatia. Each female’ s reproductive status was recorded (development of glair glands, number and diameter of external eggs, presence of hatched juveniles), as well as her morphometrical characteristics (total length, weight, abdomen size). A total of 29 A. torrentium females were caught from two Austrian populations (from which 10.34 % were with activated glair glands and 34.48 % were berried), and 112 from four Croatian populations (from which 12.50 % were with activated glair glands and 17.86 % were berried). Positive significant correlations between measured females morphological characteristics were found, but no significant correlation between the later and egg number was recorded. A weak positive correlation existed between females total length and egg diameterand within Croatian populations, whilst in Austiran populations a significant negative correlation was recorded between egg number and thier size. It was found that Croatian females are bigger than Austrian ones, and that they carry more eggs of smaller size. Based on these results implications for conservation issues for the two countries are given.

Austropotamobius torrentium; reproduction; external eggs; conservation biology

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