2017). Rapid recovery of nuclear and mitochondrial genes by genome skimming from Northern Hemisphere freshwater crayfish. -Zoologica Scripta, 46, 718-728. Molecular phylogenetics has benefited tremendously from the advent of next-generation sequencing, enabling quick and cost-effective recovery of whole mitogenomes via an approach referred to as 'genome skimming'. Recently, genome skimming has been utilised to recover highly repetitive nuclear genes such as 18S and 28S ribosomal RNA genes that are useful for inferring deeper evolutionary relationships. To address some outstanding issues in the relationships among Northern Hemisphere freshwater crayfish (Astacoidea), we sequenced the partial genome of crayfish species from Asian, North American and European genera and report the successful recovery of whole mitogenome sequences in addition to three highly repetitive nuclear genes, namely histone H3, 18S and 28S ribosomal RNA. Consistent with some previous studies using short mtDNA and nuclear gene fragments, phylogenetic analyses based on the concatenation of recovered mitochondrial and/or nuclear sequences recovered the Asian cambarid lineage as basal to all astacids and North American cambarids, which conflicts with the current taxonomic classification based on morphological and reproduction-related characters. Lastly, we show that complete H3, 18S and 28S ribosomal RNA genes can also be consistently recovered from a diverse range of animal taxa, demonstrating the potential wide utility of genome skimming for nuclear markers.

Numerous freshwater crayfish species are known to become successful invaders when introduced to new territories. One of the most invasive species in this group is the red swamp crayfish, Procambarus clarkii (Girard, 1852). In addition to other characteristics facilitating its invasiveness, it is also a vector of crayfish plague, a disease mostly lethal to crayfish of non‐North American origin. Procambarus clarkii, at present the most widespread crayfish species globally, is popular in many countries both for human consumption and as an ornamental animal. An established population of this species was documented for the first time within Indonesia, representing the first record for maritime Southeast Asia. The species is also common in the local ornamental pet trade. Infection by the crayfish plague pathogen Aphanomyces astaci Schikora was confirmed both in the outdoor population of P. clarkii and in one of the surveyed pet shops. Furthermore, A. astaci was detected in specimens of freshwater crab and shrimp species coexisting with P. clarkii. Local climatic conditions and the species temperature requirements suggest a high probability of the establishment of P. clarkii in Indonesia. Its further spread could irreversibly damage populations of many native endemic crustaceans in the country (as well as elsewhere in the region), and the thriving local aquacultures of the redclaw crayfish Cherax quadricarinatus (von Martens, 1868) may also be threatened. The total ban of P. clarkii and other crayfish species of North American origin in Indonesia is strongly recommended, especially considering that aquaculture and trade with Australasian species is a viable alternative option.

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We investigated diel habitat use of fish covering the littoral and pelagic zones of the Ř ímov Reservoir (Czech Republic) and analyzed the influence of predator presence and of shifting feeding habitats in all dominant species and age groups. Our sampling revealed distinctive diel changes of fish distribution in the reservoir, which were age-and species-dependent. The overall abundance of subadult fish in littoral habitats was significantly higher at night than during the daytime. Subadults were almost absent in pelagic habitat during the day and their presence increased during the night, although densities were smaller than in the littoral. Adults preferred the pelagic zone during the day and partly migrated to the littoral at night. Potential fish predators were most likely responsible for small fish avoidance of the littoral and pelagic zones during day. Higher availability of food in the littoral was the most important driver of the high occurrence of subadults at night. Day preference of pelagic zone by adults is most likely caused by higher profitability of this habitat in comparison with littoral. The reasons for night inshore migration of adults are not obvious, but the homogenization of their distribution or resting in the littoral could explain such behavior.

The marbled craynsn (

The phylogenetic relationships among imported ornamental crayfish belonging to the genus Cherax were inferred from a combined dataset of 3 mitochondrial genes (COI, 16S and 12S) and by comparison with available GenBank sequences of 14 Cherax species. Furthermore, the concordance of previously described species obtained from a wholesaler (Cherax boesemani, C. holthuisi and C. peknyi) with available GenBank sequences was verified based on COI with special respect to comparison with sequences assigned as Cherax species. Recently described species C. gherardiae, C. pulcher and C. subterigneus belong to the northern group of Cherax species. Comparison and analysis with other GenBank COI sequences show previously unreported diversity of New Guinean species, suggesting 5 putative new species. Surprisingly, species assigned to the subgenus Astaconephrops do not form a monophyletic clade; this subgenus should be reappraised relative to the purported typical morphological characteristic of the uncalcified patch on male chelae. Increasing importation of crayfish underscores the importance of accurate species identification. Use of basic molecular methods is a necessary requisite for documenting occurrence, abundance and population trends of target species. Consequently, it helps to support eventual conservation decision-making by stakeholders.

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