Search

Sailfin catfishes (Pterygoplichthys spp.) are a group of fishes introduced to several freshwater habitats across the globe. Sailfin catfishes are a hard-armoured fish with no economic importance as a food species. These catfishes have been reported to be affecting the growth of several economically valuable species that are native to different freshwater ecosystems. In this manuscript, we developed a TaqMan-based assay targeting the mitochondrial cytochrome c oxidase subunit 1 (COX1) gene, to specifically detect the presence of catfishes by environmental DNA (eDNA) measurements. The developed assay was screened against 16 species of fish and mussel that co-occur in the habitats along with sailfin catfishes, and the qPCR reaction did not have any non-target amplifications. The assay was further validated under laboratory conditions by measuring eDNA from tanks having different biomass of catfishes (1 and 0.5 g L−1), and the copy number of the amplified product was directly proportional to the biomass maintained in the tanks. Overall, the study provides a robust molecular tool based on eDNA measurements to facilitate detection of invasive sailfin catfishes and, in turn, contributes towards the management of the invaded habitats. Aquatic ecosystems are threatened by the introduction of several invasive fishes, for example, the Amazon sailfin catfish that has been reported to successfully invade different freshwaters around the globe, threatening the sustenance of the ecosystem. Here, we developed a specific molecular tool to accurately detect the presence and abundance of the catfish, thus contributing towards management of the aquatic biodiversity. [ABSTRACT FROM AUTHOR]

Conservation education programs centered on animal cognition seem to be effective in bringing humans closer to non-human species and thereby, influencing their conservation attitudes. Systematic evaluation of the impact of cognition-based education programs on the attitudes of participants has revealed positive feedback and an appreciation towards the species of interest. However, such evaluations are rare for species like elephants, who suffer severe conservation challenges such as high degrees of conflict with the local community. In this paper, we review the need for cognition-based education programs in elephant conservation as well as the need to evaluate these programs to assess their impact on conservation attitudes. In particular, we emphasize the need for such programs in the native ranges of elephants, which are more prone to human-elephant conflict, and argue that exposure to such programs may potentially increase the collaboration of the local community towards conservation efforts.

We review various applications of biocontrol for invasive fish and aquatic invertebrates. We adopt a broader definition of biocontrol that includes traditional methods like predation and physical removal (biocontrol by humans), and modern approaches like genetic engineering and use of microbes (including pathogens). While physical removal and predation (by native predators) are used relatively commonly, use of genetic technologies and microbes is in developmental stages. The two latter strategies are most advanced in case of the common carp (Cyprinus carpio), one of the world's most invasive fish; virus release to control carp might soon occur in Australia. Drawing from empirical examples in North America, we emphasize that biocontrol strategies are most likely to be successful if they include multiple approaches that target specific behaviors or weaknesses in pests' life histories. This is illustrated by reviewing case studies on the common carp and rusty crayfish (Orconectes rusticus) in Midwestern North America. In case of the common carp, basic research on movement patterns and recruitment bottlenecks identified a strategy where winter aggregations of adults were targeted for removal with nets, while native predators of carp eggs and larvae were instrumental in controlling carp's reproductive success. In the case of the rusty crayfish, basic research on interactions between crayfish, habitat, and native predators identified a successful strategy of stocking selected native predators to control juvenile crayfish in conjunction with physical removal of adult crayfish using traps. We are also reviewing the case of the round goby (Neogobius melanostomus) in the Great Lakes. In this example, multiple pieces of evidence (diet, bioenergetics) illustrate how initially abundant pest was brought under control (in some areas) by several species of native predators in a large, natural ecosystem. Overall, examples of successful biocontrol of aquatic pests have been rare and have relied on physical removal and predation. We expect that new technologies (e.g. genetic technologies) will occur in the next decade but will have to clear regulatory and ethical concerns before they are applied. While developing more sophisticated control techniques, we advocate for more basic research on the life history of the pests to identify behavioral or developmental weaknesses that could be targeted with specific tools to increase chances of success while minimizing impacts on native ecosystems. [ABSTRACT FROM AUTHOR]

Aquatic invasive species (AIS) are of concern in North America due to their devastating impacts on ecosystems and economies. The Great Lakes region is particularly vulnerable to AIS introduction and establishment with at least 184 nonindigenous species reported in this region from a large number of taxa including viruses, bacteria, diatoms, protozoa, arthropods, mollusks, fish, and plants. Representative species from these groups were explored, describing the features of their natural history and current efforts in prevention and control. Specifically, five AIS that are expected to spread to novel areas in the region are discussed: viral hemorrhagic septicemia virus and heterosporis (pathogens affecting fish), starry stonewort (an alga), zebra mussels (a bivalve), and carps (fishes). Novel strategies for AIS control include next-generation sequencing technologies, gene editing, mathematical modeling, risk assessment, microbiome studies for biological control, and human-dimension studies to address tensions related to AIS management. Currently, AIS research is evolving to adapt to known technologies and develop novel technologies to understand and prevent AIS spread. It was found that AIS control in this region requires a multidisciplinary approach focusing on the life history of the species (e.g., pheromones), adaptive management of anthropogenic structures (e.g., bubble curtains), and the integration of human dimensions to develop efficient management plans that integrate local citizens and management agencies. [ABSTRACT FROM PUBLISHER]

The occurrence of musth, a period of elevated levels of androgens and heightened sexual activity, has been well documented for the male Asian elephant (Elephas maximus). However, the relationship between androgen-dependent musth and adrenocortical function in this species is unclear. The current study is the first assessment of testicular and adrenocortical function in free-ranging male Asian elephants by measuring levels of testosterone (androgen) and cortisol (glucocorticoid – a physiological indicator of stress) metabolites in faeces. During musth, males expectedly showed significant elevation in faecal testosterone metabolite levels. Interestingly, glucocorticoid metabolite concentrations remained unchanged between musth and non-musth periods. This observation is contrary to that observed with wild and captive African elephant bulls and captive Asian bull elephants. Our results show that musth may not necessarily represent a stressful condition in free-ranging male Asian elephants. [ABSTRACT FROM AUTHOR]