Levels of phenoloxidase (Po), trypsin and lysozyme activities were determined following 48 hours exposing freshwater crayfish (Pontastacus leptodactylus) weighing 59.8&plusmn;3.4g to different low pH values of 6.5, 5.5, 4 and 2.5 at 20-23˚C. Significant decrease were found (p<0.01) in levels of Po and trypsin activities in crayfish haemocyte lysate supernatant (HLS) at pHs 5.5 and 4 compared to...

Crayfish, carp, and crab threaten the consumer’s health due to enrichment of toxic elements. The concentration elements (As, Cr, Cd, Pb) in these aquatics was less investigated simultaneously situ. In this study, from same site Hanchuan, Hubei Province, China were measured by ICP-MS assess four them risk consumer. results showed that concentrations muscle lower than those hepatopancreas/ liver,...

This is the first reported case of eye injury caused by a crayfish antenna. A 20-year-old male crayfish diver sustained a scleral penetrating injury that led to a subconjunctival abscess. The foreign body was histologically similar to a crayfish antenna.

Omnivores can impact ecosystems via opposing direct or indirect effects. For example, omnivores that feed on herbivores and plants could either increase plant biomass due to the removal of herbivores or decrease plant biomass due to direct consumption. Thus, empirical quantification of the relative importance of direct and indirect impacts of omnivores is needed, especially the impacts of invas...

Predators sometimes provide biotic resistance against invasions by nonnative prey. Understanding and predicting the strength of biotic resistance remains a key challenge in invasion biology. A predator's functional response to nonnative prey may predict whether a predator can provide biotic resistance against nonnative prey at different prey densities. Surprisingly, functional responses have no...

Cherax (Astaconephrops) gherardii n. sp. is a moderate burrowing crayfish endemic to the Ajamaru Lakes of West Papua, Indonesia. This species is one of the crayfish species from this region that are exploited for ornamental purposes. Its commonly used commercial name in the pet trade is "Rainbow Crayfish" or "Blue Moon Crayfish", and its native name is "udang kuku biru". The new species is gene...

In a replicated field experiment we studied the effects of natural densities of two exotic consumers, the predatory and herbivorous signal crayfish (Pacifastacus leniusculus) and the predatory rainbow trout (Oncorhynchus mykiss), on multiple trophic levels of a pond community. The goals were to: (1) determine the individual and combined effects of predators on macroinvertebrates, macrophytes, a...

The neural systems that control escape behavior have been studied intensively in several animals, including mollusks, fish and crayfish. Surprisingly little is known, however, about the activation and the utilization of escape circuits during prey-predator interactions. To complement the physiological and anatomical studies with a necessary behavioral equivalent, we investigated encounters betw...