Skin and Blood Microbial Signatures of Sedentary and Migratory Trout (Salmo trutta) of the Kerguelen Islands

Abstract

Our understanding of how microbiome signatures are modulated in wild fish populations remains poorly developed and has, until now, mostly been inferred from studies in commercial and farmed fish populations. Here, for the first time, we have studied changes in the skin and blood microbiomes of the Salmo trutta population of the volcanic Kerguelen archipelago located at the northern limit of the Antarctic Ocean. The Kerguelen Islands present a natural framework of population expansion and reveal a likely situation representing further climate change in distribution areas. Our results showed that S. trutta of the Kerguelen Islands has a microbiome signature distinct from those of salmonids of the Northern Hemisphere. Our study also revealed that the skin and blood microbiomes differ between sedentary and migratory S. trutta. While 18 phyla were shared between both groups of trout, independent of the compartment, 6 phyla were unique to migratory trout. Further analyses showed that microbiome signatures undergo significant site-specific variations that correlate, in some cases, with the peculiarity of specific ecosystems. Our study also revealed the presence of potential pathogens at particular sites and the impact of abiotic factors on the microbiome, most notably due to the volcanic nature of the environment. This study contributes to a better understanding of the factors that modulate the microbiome signatures of migratory and sedentary fish populations. It will also help to better monitor the impacts of climate change on the colonization process in the sub-Antarctic region.

Divergent bacterial landscapes: unraveling geographically driven microbiomes in Atlantic cod

“…In medicine, the characterization of the peripheral blood-derived microbiome signature, defined as blood microbial DNA, is increasingly used by clinicians to assess an individual's health status, detect dysbiosis and potential pathogens, or as a biomarker to inform disease severity and progression 33 – 37 . This concept is also gaining momentum in ecology as the circulating microbiome of dogs, bovine, wild birds and wild fish populations were recently studied, showing that the genetic structure of the blood microbiome, just as in humans, is modulated by genetic and spatiotemporal factors, as well as disease conditions 20 , 38 – 41 . In the present study, the observed shift toward the dominance of Nitrobacter and Sediminibacterium suggests that environmental factors severely impact the blood microbiome signature.…”

Seafloor and Ocean Crust Structure of the Kerguelen Plateau from Marine Geophysical and Satellite Altimetry Datasets

“…Its high environmental value is explained by the unique wildlife structure, which includes vulnerable species. The remote location of the archipelago-4000 km from South Africa and Australia [69,70]-has created ideal conditions for preserving unique flora and fauna of the Kerguelen Archipelago. The presence of rare Antarctic plant species and high biodiversity is closely linked to the soil developed on the basaltic basement and the specific geological substrate of volcanic origin.…”