Spatial dynamics of the noble crayfish (Astacus astacus, L.) in the Paklenica National Park

Abstract

The aim of this work was to analyse the spatial dynamics of a noble crayfish population inhabiting the Velika Paklenica Stream (Paklenica National Park, Croatia). The study was conducted in July 2000, and between March and September 2002. Crayfish were trapped by baited LiNi traps and hand-made traps at two localities over 25 nights. We recorded the precise position of the captured crayfish, their sex, and total length. Crayfish were individually marked and then released back into the stream at the same spot where they were caught. Spatial analyses included determination of movement direction, distribution type, home range, total distance travelled, and mean daily movement. A mean home range of approximately 19 m was calculated. No difference in home range between the sexes was found. There was a large individual variation in the extent of movement without any effect of sex or size. RÉSUMÉDynamique spatiale des écrevisses à pieds rouges (Astacus astacus L.) dans le Parc National Paklenica L'objectif de notre recherche était l'analyse de la dynamique spatiale de la population d'écrevisses à pieds rouges dans la rivière Velika Paklenica située dans le Parc National Paklenica, en Croatie. La recherche a été menée en juillet 2000 et entre mars et septembre 2002. Les écrevisses ont été capturées avec des nasses LiNi et des nasses faites à la main, dans deux localités, pendant 25 nuits au total. Nous avons relevé la position précise des écrevisses capturées, leur sexe et leur longueur totale. Les écrevisses ont été marquées individuellement, avec des trous dans les uropodes et le telson, et relâchées ensuite. L'analyse spatiale a compris la détermination de la direction de mouvement, du type de distribution spatiale, de la taille de l'habitat, de la distance parcourue et du déplacement moyen quotidien. La distribution des écrevisses, comme on pouvait s'y attendre, est agrégée spatialement. La dimension moyenne de l'habitat de 19.03 m correspond à des données trouvées dans la littérature, mais aucune différence entre les sexes n'a été trouvée.

Movement patterns of juvenile and adult noble crayfish (Astacus astacus) in a small stream, determined by radiotelemetry

“…After the crayfish migrated, they usually did not return to a previously occupied shelter, so homing behaviour obviously did not play any significant role at the locality. The prevailing upstream movement is in agreement with observations made by Hudina et al (2008), Kadlecová et al (2012) and Daněk et al (2018), and it probably helps crayfish to counteract occasional passive downstream movements during extreme flow (Momot, 1966). Migrations of juvenile individuals over longer distances may Asterisks indicates significant differences in behavioural metrics between juvenile and adult crayfish during particular times of day.…”

“…be associated with their smaller drag when moving against the flow (Hudina et al, 2008), but they may also be connected with their preference of shallower parts of the watercourse or its tributaries higher upstream, compared to the suggested preference of adults for deeper sections (Skurdal et al, 1988;Harrison et al, 2006).…”

An investigation on the population parameters of freshwater crayfish(Astacus leptodactylus Esch., 1823) in Lake İznik (Bursa)

“…In some seasons, in the ratios of the individuals caught, sex differences could be seen to a large extent. This is because females and males can engage in different activities seasonally (Westin and Gydemo, 1989;Hudina et al, 2008). As an example, more males can be caught compared to females, especially during the spawning period (Fenouil and Chaix, 1985;Ackefors, 1999;Alekhnovich et al, 1999;Grandjean et al, 2000;Capurro et al, 2007).…”

A study on the morphometric characteristics ofAstacus leptodactylusinhabiting the Thrace region of Turkey

“…The lower catches during winter and spring with respect to summer and autumn could be related to minor activity of crayfish after breeding and later, for females only, after spawning (Gherardi et al, 1997;Kirjavainen and Westman, 1999;Grandjean et al, 2000;Capurro et al, 2007). Differences in sex ratios over seasons could mainly be due to differences in the activity pattern of males and females (Westin and Gydemo, 1989;Hudina et al, 2008). The length-weight, carapace length-carapace width, carapace width-total length, chela length-total length and chela width-total length relationships of males and females showed positive allometric growth (b > 3).…”