#1
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Πληροφορίες για astacus leptodactylus?
Καλησπέρα σε όλους,
Έχει κανείς πληροφορίες για το είδος astacus leptodactylus? Είναι καραβιδα γλυκού νερού. Θα ήθελα να μάθω περισσότερα για διατροφή, αναπαραγωγή κλπ. Έψαξα και δεν βρήκα κάτι που να με βοηθάει στο ιντερνετ Ευχαριστω |
#2
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Biology
From Gherardi and Souty-Grosset (2010): In addition, this species is active during the day and during winter.Furthermore, it is an omnivorous species, but demonstrates a preference for zoobenthos, which makes up to 97.2% of the weight of its food in the first year of life in the Caspian Sea. Size, Weight, and Age Range From NatureSpot (2015): Turkish Crayfish are also known as Turkish Narrow-clawed Crayfish and are usually about 15 cm long but can be up to 30 cm. Environment From Gherardi and Souty-Grosset (2010): This species is found in both fresh and brackish waters, e.g. lagoons, estuaries, as well as running freshwater rivers in the Ponto-Caspian Basin. Across Europe it is found in lakes, canals and rivers. It is tolerant to changes in temperature, low oxygen content, and low water transparency, and is known to occur in saline conditions such as estuaries. Tolerance experiments indicated that O+ juveniles and adults are well adapted for surviving salinities of at least 21ppt in the long term, and will tolerate being transferred directly back into freshwater. However, their ability to colonize the estuarine environment may be restricted to areas of low salinity (i.e. 7ppt) due to the adverse effects of seawater on egg development and hatching (Holdich, Harlioglu and Firkins 1997). Climate/Range No specific records on climate/range were found for Pontastacus leptodactylus. Short Description From NatureSpot (2015): Pale yellow to pale green in colour [sic]. Sides of carapace very rough. Two pairs of ridges behind the eye sockets. Rostrum well developed with parallel sides and long apex. Claws: Long and narrow, upper surface rough, underside same colour [sic] as body. Impacts of Introductions The following detail actual impacts from introduced populations of Pontastacus leptodactylus. From Chucholl (2016): Noble crayfish [Astacus astacus] and narrow-clawed crayfish [Pontastacus leptodactylus], by contrast, compete for the same lentic habitats, as evidenced by several lakes in the study area in which the former native species was displaced by narrow-clawed crayfish over the course of several years (Sauter and Chucholl, unpubl. data). From Harlioglu (1996): The results presented here show that both juvenile P. leniusculus and A. leptodactylus can have a dramatic impact on plant and macroinvertebrate communities over a long time period (Experiments 1 and 2) as well as over a short time period (Experiments 3,4 and 5). For example, 12 or 13 mm (CL) juveniles of the two species had a detrimental impact on Cladophora and Asellus, and even Planorbis contort us number. However, the impact of the 12 or 13 mm (CL) juveniles on the number of P. contortus was not as fast as was observed on Cladophona and Asellus. In comparison to the impact of 12 or 13 mm (CL) juveniles on the snail species, the impact of 25 or 27 mm (CL) juveniles of the two species was more significant. It can be concluded from this study that even low densities of juvenile P. leniusculus and A. leptodactylus can have an adverse effect on plant and macroinvertebrate communities (Experiments 1 and 2). The results show that both juvenile and adult P. leniusculus and A. leptodactylus, and adult A. pallipes consumed fish eggs at a high rate. Although there was no significant difference between adults of P. leniusculus and A. leptodactylus, the consumption rate of carp eggs and brown trout eggs by juvenile A. leptodactylus was significantly higher than that of juvenile P. leniusculus in some cases. The following detail potential impacts from introduced populations of Pontastacus leptodactylus. From NatureSpot (2015): More aggressive and faster breeding than our [United Kingdom’s] native White-clawed crayfish. From Stucki and Romer (2001): Since A. leptodactylus is known to be a good colonizer and a strong competitor of other crayfish species (Cukerzis, 1968, 1973, 1988; KΓΆksal, 1988; Holdich, 1999), we suppose that A. leptodactylus displaced the formerly present native species A. astacus and A. torrentium from numerous lakes and ponds. From Gherardi (2007): As a consequence, because of their large numbers, coupled with their wide trophic plasticity, NICS exert a greater direct (through consumption) or indirect (through competition) effect on the other biota, particularly on crayfish species, benthic fish, mollusks, and macrophytes (NystrΓΆm et al. 1996). This is also true for those species that apparently have not caused much environmental degradation, such as A. leptodactylus in England whose high numbers are producing considerable problems for anglers (Holdich 1999b). From Gherardi and Souty-Grosset (2010): These features and the high fecundity and fast growth suggest that it can outcompete Astacus astacus. From Soes and Koese (2010): Impact Not recorded. Large quantities of the narrow-clawed crayfish were observed in a reservoir (Craneweyer, now primary [sic] used for recreation and fishing) near Kerkrade in Limburg, 2009, which raised some concern among local fisherman. From Harlioglu (1996): However, the study also showed that the adult of P. leniusculus and A. leptodactylus would have a dramatic impact on the juveniles of A. pallipes if they had been introduced in a native crayfish population where the juveniles of the native crayfish had released from their mother. Αυτα βρηκα. https://www.fws.gov/fisheries/ANS/er...ylus-FINAL.pdf |
#3
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Ωραία.
Να δω τι θα τις ταΐσω τωρα..... Δοκιμασα ο, τι είχα σε πελλετ αλλά δεν συγκινούνται. Ίσως φταίει το σοκ της προσαρμογής. Θα δω σε λίγες μέρες. Επειδή απέκτησα 8-9 χωρίς να το θέλω, και επειδή δεν έχω τον απαιτούμενο χώρο, μάλλον θα δώσω τις 5-6. Δωρεάν. Θα δω πως θα πάνε και θα επανέλθω. Ζωηρές ειναι πάντως και κινητικές. |
Συνδεδεμένοι χρήστες που διαβάζουν αυτό το θέμα: 1 (0 μέλη και 1 επισκέπτες) | |
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