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Crayfish of Serbia and Montenegro — the population status and the level of endangerment

2008; Brill; Volume: 81; Issue: 10 Linguagem: Inglês

10.1163/156854008x374496

1568-5403

Vladica Simić, Ana Petrović, Milka Rajković, Momír Paunović,

Marine Biology and Ecology Research

In Serbia and Montenegro, four species of crayfish have been identified: three native, i.e., Astacus astacus (river crayfish), Astacus leptodactylus (Danube crayfish) and Austropotamobius torrentium (spring crayfish), as well as one non-indigenous species, Orconectes limosus (American crayfish). According to results presented, which comprise analyses of the data from a 60-year period, A. astacus is the most endangered species of crayfish in Serbia, as well as in Montenegro. The factors that influence the reduction of populations of this species are: pollution, habitat fragmentation, diseases, competition with A. leptodactylus, as well as isolation of the populations. According to IUCN criteria (Version 3.1), the degree of the endangerment of A. astacus in Serbia is evaluated as Endangered (EN), which is a higher degree than the international level determined for this species, i.e., Vulnerable (VU). Populations the river crayfish in the area of Montenegro are in better condition, especially in the area of the upper course of the Zeta River. However, the populations of river crayfish in Montenegro are endangered by overfishing. Among native crayfishes, the least negative changes were determined in populations of A. torrentium. In both countries, the status of this species, according to IUCN criteria, was designated as Lower Risk/Near Threatened (LR/nt), which is lower than the international level of this species: Vulnerable. During the past 30 years, A. leptodactylus has extented its area of distribution from the Danube River to other waters in Serbia (reservoirs and the Morava River). The last five years, the Danube crayfish has been endangered by the penetration of the invasive American crayfish. The abundance ratio of these two species in the Djerdap stretch of the Danube River was estimated as O. limosus : A. leptodactylus = 5 : 2. Serbie et au Montenegro, quatre especes d'ecrevisses ont ete identifiees: trois especes indigenes, Astacus astacus (ecrevisse a pieds rouges), Astacus leptodactylus (ecrevisse a pattes greles), et Austropotamobius torrentium (ecrevisse des torrents), ainsi qu'une espece non-indigene, Orconectes limosus (ecrevisse americaine). Selon les resultats presentes, qui comprennent les analyses de donnees sur une periode de 60 ans, A. astacus est l'espece d'ecrevisse la plus menacee en Serbie, ainsi qu'au Montenegro. Les facteurs qui influencent la reduction des populations de cette espece sont: la pollution, la fragmentation de l'habitat, les maladies, la competition avec A. leptodactylus, ainsi que l'isolement des populations. Selon les criteres de l'IUCN (Version 3.1), le degre de menace d'extinction de A. astacus en Serbie est evalue a En Danger (EN), ce qui est un degre plus eleve que le niveau international determine pour cette espece, c'est a dire Vulnerable (VU). Les populations de l'ecrevisse a pattes rouges dans la region du Montenegro sont en meilleures conditions, en particulier dans la zone du cours superieur de la riviere Zeta. Cependant, les populations d'ecrevisse a pattes rouges du Montenegro sont menacees par la surpeche. Parmi les ecrevisses indigenes, les changements les moins negatifs ont ete determines chez les populations d'A. torrentium. Dans les deux pays, le statut de cette espece, selon les criteres de l'IUCN, a ete designe comme Preoccupation Mineure/Quasi Menace (LR/nt), ce qui est moins eleve que le niveau international de cette espece: Vulnerable. Au cours des 30 dernieres annees, A. leptodactylus a etendu son aire de repartition du Danube aux autres eaux de Serbie (reservoirs et Morava). Au cours des cinq dernieres annees l'ecrevisse a pattes greles a ete mise en danger par la penetration de l'ecrevisse americaine, espece invasive. Le taux d'abondance de ces deux especes dans la region de Djerdap sur le cours du Danube a ete estime a: O. limosus : A. leptodactylus = 5 : 2.