The noble crayfish (Astacus astacus L.) in Poland - past, the present and perspectives
2002
Struzynski, W.,Warsaw Agricultural University (Poland). Div. of Zoology | Krzywosz, T.,Institute of Inland Fisheries, Olsztyn (Poland)
Diminishing the noble crayfish sites in Poland has been observed for over 70 years. Cyclic inventories carried out over the whole country and in selected regions revealed a distinct, proceeding retreat of the species. At the end of the fifties of the XX century, 342 sites of the noble crayfish were registered while now there are only 56 of them. Population of the noble crayfish is closely correlated with its catches registered since 1949. During c. 50 years the catches dropped from 55474 kg in 1958 to nearly 500 kg in 2000. In spite of such a dramatic situation of the native crayfishes, no work aiming at the restitution of species was undertaken until 1999. Since then (after 9 years of studies verifying present number of crayfish sites) an attempt was undertaken to restore the native crayfish population in selected waters. Noble crayfish were released in total to 31 rivers and 16 lakes. Preliminary effects of stocking measured in 2001 demonstrated the activity of individuals, their sloughs and fragments of their carapaces in otter (Lutra lutra) feces found in 41 sites
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