In the last ten years Araipama gigas, commonly known as pirarucu, expanded its distribution upstream into the Madeira River rapids where it is not a native species. The invasion was favored by escapes from Peruvian fish farms upstream in the Madeira River Basin, where they have been raising pirarucu since the 1970s. Although the Madeira River rapids had formerly represented a geographical barrier to this invasion by limiting floodplain habitats, the construction of the Santo Antônio and Jirau dams in 2011 flooded the two most important falls, replacing the rapids stretch with a lentic or semi-lentic habitat favoring the invasion of A. gigas. Since construction of the dams, fisheries reports have been marked by the decrease of traditional commercial species, coupled with the presence of invasive populations of A. gigas. This example highlights a major emergent threat to artisanal fishing in the Amazonian freshwater system: government policies favoring dam construction and the consequent spread of native fish species used in aquaculture to new regions upstream of waterfalls where they are not native.

This study was conceived to detect skin mites in social mammals through real-time qPCR, and to estimate taxonomic Demodex and further Prostigmata mite relationships in different host species by comparing sequences from two genes: mitochondrial 16S rRNA and nuclear 18S rRNA. We determined the mite prevalence in the hair follicles of marmots (13%) and bats (17%). The high prevalence found in marmots and bats by sampling only one site on the body may indicate that mites are common inhabitants of their skin. Since we found three different mites (Neuchelacheles sp, Myobia sp and Penthaleus sp) in three bat species (Miotis yumanensis, Miotis californicus and Corynorhinus townsendii) and two different mites (both inferred to be members of the Prostigmata order) in one marmot species (Marmota flaviventris), we tentatively concluded that these skin mites 1) cannot be assigned to the same genus based only on a common host, and 2) seem to evolve according to the specific habitat and/or specific hair and sebaceous gland of the mammalian host. Moreover, two M. yumanensis bats harbored identical Neuchelacheles mites, indicating the possibility of interspecific cross-infection within a colony. However, some skin mites species are less restricted by host species than previously thought. Specifically, Demodex canis seems to be more transmissible across species than other skin mites. D. canis have been found mostly in dogs but also in cats and captive bats. In addition, we report the first case of D. canis infestation in a domestic ferret (Mustela putorius). All these mammalian hosts are related to human activities, and D. canis evolution may be a consequence of this relationship. The monophyletic Demodex clade showing closely related dog and human Demodex sequences also supports this likely hypothesis.

Invasive species are a widespread threat to stream ecosystems across the planet. In Southern California, USA, the invasive red swamp crayfish Procambarus clarkii (Girard, 1852) poses a significant threat to native aquatic fauna. Studies have suggested that artificial refuge traps (ARTs) resembling crayfish burrows can be used to remove invasive crayfish, but, to date, no studies have focused on optimizing ART design and deployment to maximize crayfish catch. This month-long study tested the effect of modifications on ART diameter, color, and soak time on P. clarkii catch effectiveness across 160 traps. We evaluated catch data by creating multiple candidate generalized linear mixed models predicting P. clarkii catches with different modeling parameterizations and a priori hypothesized predictor variables. During the study period, ARTs removed a total of 240 red swamp crayfish with no incidental bycatch. Larger P. clarkii (2-6-cm carapace length) were found more frequently in 5.1-cm-diameter traps, and smaller P. clarkii (1-4 cm) were found more frequently in 2.5-cm-diameter traps. Catch numbers varied between trap types, with black-colored 5.1-cm-diameter traps removing the greatest amount of the total P. clarkii caught in the study (mean 5 0.27, SD 5 0.29; 35% of the total caught) and black-colored 2.5-cm-diameter traps removing the least amount (mean 5 0.09, SD 5 0.55; 12% of the total). Further, ART deployment duration was an important predictor variable for candidate models, where ARTs with 4-d and 7-d deployment durations had lower catch/unit effort than traps with 1-d and 2-d deployments. This factorial experiment is the 1 st study to suggest specific design modifications to ARTs that optimize invasive red swamp crayfish removal without incurring non-target incidental bycatch. This study demonstrates that ARTs can be a valuable tool for conservation managers interested in restoring streams through invasive crayfish removal, especially where there are sensitive biological resources.