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Using the most comprehensive fish occurrence database, we evaluated the importance of ecological and historical drivers in diversity patterns of subdrainage basins across the Amazon system. Linear models reveal the influence of climatic conditions, habitat size and sub-basin isolation on species diversity. Unexpectedly, the species richness model also highlighted a negative upriver-downriver gradient, contrary to predictions of increasing richness at more downriver locations along fluvial gradients. This reverse gradient may be linked to the history of the Amazon drainage network, which, after isolation as western and eastern basins throughout the Miocene, only began flowing eastward 1-9 million years (Ma) ago. Our results suggest that the main center of fish diversity was located westward, with fish dispersal progressing eastward after the basins were united and the Amazon River assumed its modern course toward the Atlantic. This dispersal process seems not yet achieved, suggesting a recent formation of the current Amazon system.
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http://dx.doi.org/10.1126/sciadv.aav8681 | DOI Listing |
J Fish Dis
September 2025
Guangdong Provincial Water Environment and Aquatic Products Security Engineering Technology Research Center, Guangzhou Key Laboratory of Aquatic Animal Diseases and Waterfowl Breeding, College of Animal Sciences and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, Guangdong
Vibrio infections cause enteritis in grouper fish, leading to high mortality and stunted growth, which is a major challenge for aquaculture. Oligochitosans, marine prebiotics with bioactive properties, have proven their potential for growth promotion and immune regulation. However, the impacts of Vibrio harveyi on the gut microbiome of grouper fish and the potential of oligochitosans to modulate these effects remain poorly understood.
View Article and Find Full Text PDFMol Ecol
September 2025
Museum of Vertebrate Zoology, University of California Berkeley, Berkeley, California, USA.
Many North American game animals experienced severe population declines during the 19th century due to market hunting. However, estimates of the timing and magnitude of these declines often rely on anecdotal evidence, which makes it difficult to understand the lasting impacts of hunting pressures versus climate or landscape changes on the genetic diversity of contemporary populations. Historical reports suggest the California quail (Callipepla californica) suffered more significant hunting pressure in the late 19th century relative to either Gambel's (Callipepla gambelii) or mountain quail (Oreortyx pictus).
View Article and Find Full Text PDFActa Trop
September 2025
Morpho-Molecular Integration Laboratory and Technologies (LIMT), Institute of Animal Health and Production (ISPA), Federal Rural University of the Amazon (UFRA), Belém, Pará, Brazil; Postgraduate Program in Animal Health and Production in the Amazon (PPGSPAA), Federal Rural University of the Amazo
The Brazilian Amazon estuary is a highly dynamic environment, characterized by substantial organic matter input and a rich diversity of fish species that utilize this ecosystem for feeding and reproduction. Despite its ecological relevance, ichthyo-parasitological research in the region remains limited, particularly regarding the diversity of parasitic species within the class Myxozoa. Among the fish species for which parasitological data are still scarce is the Pacamã frogfish, Batrachoides surinamensis (Bloch and Schneider, 1801), a demersal species that feeds on small invertebrates and fish.
View Article and Find Full Text PDFJ Environ Manage
September 2025
Centre for Applied Water Science, University of Canberra, ACT, Australia; Department of Zoology, University of Otago, Dunedin, New Zealand.
One mechanism for improving the resilience of freshwater systems affected by climate change is to use environmental water to support refugial habitats which allow species, ecosystems and functions to persist and recover after severe droughts. We applied systematic conservation planning (SCP) to prioritise wetlands and lakes with the aim of informing the delivery of environmental water for the creation and protection of refugia habitat in the Murray-Darling Basin, Australia. SCP uses a complimentary algorithm to generate planning solutions that protect all target ecological assets for the lowest "cost" of the management constraints considered.
View Article and Find Full Text PDFBMC Microbiol
September 2025
Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada.
Background: A plant-focused, healthy dietary pattern, such as the Mediterranean diet enriched with dietary fiber, polyphenols, and polyunsaturated fats, is well known to positively influence the gut microbiota. Conversely, a processed diet high in saturated fats and sugars negatively impacts gut diversity, potentially leading to weight gain, insulin resistance, and chronic, low-grade inflammation. Despite this understanding, the mechanisms by which the Mediterranean diet impacts the gut microbiota and its associated health benefits remain unclear.
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