نتایج جستجو برای: crayfish
تعداد نتایج: 3533 فیلتر نتایج به سال:
The study of individual movement patterns and habitat choice is a fundamental step to assess an invasive species’ range extension and to inform possible management options. The spiny-cheek crayfish is an invasive species currently spreading in Europe and also in Lake Constance. This is of concern because the greater Lake Constance area still holds refugial populations of native crayfish that mi...
Several North American crayfish species have so far been identified as carriers of the crayfish plague agent Aphanomyces astaci. The pathogen is responsible for the declines of thousands of European crayfish populations. Currently, one of the introduction pathways of North American crayfish species is the aquarium trade which may sometimes be followed by intentional release or unintentional esc...
The parthenogenetic all-female marbled crayfish is a novel research model and potent invader of freshwater ecosystems. It is a triploid descendant of the sexually reproducing slough crayfish, Procambarus fallax, but its taxonomic status has remained unsettled. By cross-breeding experiments and parentage analysis we show here that marbled crayfish and P. fallax are reproductively separated. Both...
The parthenogenetic all-female marbled crayfish is a novel research model and potent invader of freshwater ecosystems. It is a triploid descendant of the sexually reproducing slough crayfish, Procambarus fallax, but its taxonomic status has remained unsettled. By cross-breeding experiments and parentage analysis we show here that marbled crayfish and P. fallax are reproductively separated. Both...
Social behavior depends on sensory input from the visual, mechanical and olfactory systems. One important issue concerns the relative roles of each sensory modality in guiding behavior. The role of visual inputs has been examined by isolating visual stimuli from mechanical and chemosensory stimuli. In some studies (Bruski & Dunham, 1987: Delgado-Morales et al., 2004) visual inputs have been rem...
-FO~ the incised, sand-bed streams of northcentral Mississippi, USA, fish predation is one plausible mechanism to explain both relatively low crayfish densities and differences in stream size occupied by various native crayfishes. I conducted two mesocosm experiments to test effects of a fish predator (channel catfish, Ictalurus punctahls) on the survival and size structure of native crayfishes...
The crayfish's lateral giant escape response, a relatively simple behavioral reaction, is readily modulated in certain situations. For example, when a crayfish is restrained, its lateral giant (LG) fibers--command neurons that mediate the escape response--are strongly inhibited (Krasne and Wine, 1975). Previous work (Glanzman and Krasne, 1983) had suggested that serotonin (5-HT) might mediate t...
Crayfish: Northern crayfish Orconectes virilis Louisiana crayfish Procambarus clarkii Water nymph crayfish Orconectes nais Rusty crayfish Orconectes rusticus Utah is inhabited by a single native crayfish known as the Pilose crayfish Pacifastacus (Hobbsastacus) gambelii. Its native range is in northern Utah’s Bear River, Weber River and Ogden River drainages and in the Raft River Mountain’s drai...
The aim of this study was to screen potential probiotic bacteria against Aeromonas hydrophila and determine the effects of antagonistic bacteria and a commercial product containing lactic acid bacteria on the survival and growth of stage II Astacus leptodactylus juveniles. For this purpose, a total of 110 bacterial strains were isolated from adult, stage II crayfish juveniles and rearing water ...
Submerged macrophytes enhance water transparency and aquatic biodiversity in shallow water ecosystems. Therefore, the return of submerged macrophytes is the target of many lake restoration projects. However, at present, north-western European aquatic ecosystems are increasingly invaded by omnivorous exotic crayfish. We hypothesize that invasive crayfish pose a novel constraint on the regenerati...
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