Size structure, maturity size, growth and condition index of stone crayfish (Austropotamobius torrentium) in North-West Croatia

Austropotamobius torrentium (Schrank, 1803), the smallest species of freshwater crayfish from the family Astacidae, is considered a vulnerable species, protected by international laws. Since it has never been economically important, it has not been frequently studied. Therefore, the results presente...

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Main Authors: Maguire I., Klobučar G.
Format: Article
Language:English
Published: EDP Sciences 2011-06-01
Series:Knowledge and Management of Aquatic Ecosystems
Subjects:
Online Access:http://dx.doi.org/10.1051/kmae/2011026
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author Maguire I.
Klobučar G.
author_facet Maguire I.
Klobučar G.
author_sort Maguire I.
collection DOAJ
description Austropotamobius torrentium (Schrank, 1803), the smallest species of freshwater crayfish from the family Astacidae, is considered a vulnerable species, protected by international laws. Since it has never been economically important, it has not been frequently studied. Therefore, the results presented in this paper are a contribution to the knowledge on stone crayfish’s population size structure, size at maturity, growth, and condition index throughout the year, as a possible tool for evaluating protection and restocking measures of this threatened species. The research included three stone crayfish populations with 1492 specimens in the “Medvednica” Nature Park, north-west Croatia, during a period of 18 months. In all the populations studied, crayfish of a total length between 5 and 8 cm prevailed. Activity of different size classes had a seasonal pattern that could be connected to different crayfish activities throughout the year. Appearance of sexual maturity within the populations coincides with the crayfish total length between 5 and 6 cm, after which allometric growth of males’ claws was recorded. On average males gain 0.42–0.72 cm and 2.65–4.30 g per moult, while females gain 0.44–0.70 cm and 2.04–3.83 g. Crayfish condition varied throughout the year with, in general, both juvenile and adult males having higher condition indices than juvenile and adult females in all three populations. In addition, adult crayfish were in significantly better condition in the autumn, whereas juveniles had higher condition indices in the summer.
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spelling doaj.art-ff5521ec645647b786fe162b3ecdf9972022-12-21T21:11:35ZengEDP SciencesKnowledge and Management of Aquatic Ecosystems1961-95022011-06-0104011210.1051/kmae/2011026kmae110014Size structure, maturity size, growth and condition index of stone crayfish (Austropotamobius torrentium) in North-West CroatiaMaguire I.0Klobučar G.1University of Zagreb, Faculty of Science, Department of ZoologyUniversity of Zagreb, Faculty of Science, Department of ZoologyAustropotamobius torrentium (Schrank, 1803), the smallest species of freshwater crayfish from the family Astacidae, is considered a vulnerable species, protected by international laws. Since it has never been economically important, it has not been frequently studied. Therefore, the results presented in this paper are a contribution to the knowledge on stone crayfish’s population size structure, size at maturity, growth, and condition index throughout the year, as a possible tool for evaluating protection and restocking measures of this threatened species. The research included three stone crayfish populations with 1492 specimens in the “Medvednica” Nature Park, north-west Croatia, during a period of 18 months. In all the populations studied, crayfish of a total length between 5 and 8 cm prevailed. Activity of different size classes had a seasonal pattern that could be connected to different crayfish activities throughout the year. Appearance of sexual maturity within the populations coincides with the crayfish total length between 5 and 6 cm, after which allometric growth of males’ claws was recorded. On average males gain 0.42–0.72 cm and 2.65–4.30 g per moult, while females gain 0.44–0.70 cm and 2.04–3.83 g. Crayfish condition varied throughout the year with, in general, both juvenile and adult males having higher condition indices than juvenile and adult females in all three populations. In addition, adult crayfish were in significantly better condition in the autumn, whereas juveniles had higher condition indices in the summer.http://dx.doi.org/10.1051/kmae/2011026stone crayfishgrowthmaturity sizecondition indexCroatia
spellingShingle Maguire I.
Klobučar G.
Size structure, maturity size, growth and condition index of stone crayfish (Austropotamobius torrentium) in North-West Croatia
Knowledge and Management of Aquatic Ecosystems
stone crayfish
growth
maturity size
condition index
Croatia
title Size structure, maturity size, growth and condition index of stone crayfish (Austropotamobius torrentium) in North-West Croatia
title_full Size structure, maturity size, growth and condition index of stone crayfish (Austropotamobius torrentium) in North-West Croatia
title_fullStr Size structure, maturity size, growth and condition index of stone crayfish (Austropotamobius torrentium) in North-West Croatia
title_full_unstemmed Size structure, maturity size, growth and condition index of stone crayfish (Austropotamobius torrentium) in North-West Croatia
title_short Size structure, maturity size, growth and condition index of stone crayfish (Austropotamobius torrentium) in North-West Croatia
title_sort size structure maturity size growth and condition index of stone crayfish austropotamobius torrentium in north west croatia
topic stone crayfish
growth
maturity size
condition index
Croatia
url http://dx.doi.org/10.1051/kmae/2011026
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