An outbreak of disease that has affected sea stars for more than a decade could have found a shelter in the central coast of British Columbiaaccording to a study published in the magazine Proceedings of the Royal Society B.
Recent investigations have identified populations of the Sunflower Sea Star (Pycnopodia helianthoides) that they seem to prosper in these cold and deep waters, which suggests that the environmental conditions of the fjords could offer protection against the devastating disease known as sea star wear syndrome (Sswdfor its acronym in English).
He Sswdwhich was first detected in 2013 along the Pacific coast of North America, has caused a decrease Massive in seafood populations, with losses greater than the 90% In some species, including the Surrasol Sea star, now critically listed as Danger of extinction by the International Union for the Conservation of Nature (IUCN).
According to the medium Science Newsthis disease affects some 20 species and causes body deformations, injuries and rapid disintegration of affected individuals.
The researchers, led by the Hakai Institute And in collaboration with the Central Coast Indigenous Resource Alliance (CCIRA)biodiversity surveys in coastal habitats from 2013 to 2023.
The results showed that sea stars were mainly in waters cold, deep and salinas, while populations in the outer islands were more exposed to warmer temperatures and less salinity.
According to the study, the lowest temperatures in the fjords could slow down the progression of the disease, a finding that coincides with previous research that has shown that higher temperatures are associated with more serious SSWD shoots.
In the latter, the disease prevented sea stars from reaching the adulthoodwhile in these regions, healthier populations were observed and with a greater proportion of adult individuals.
This pattern suggests that fjords could act as an environmental refuge, protecting sea stars from the most severe effects of the SSWD.
The discovery of these resistant populations has important implications for conservación of the species.
According to Science NewsSunflower sea stars play a crucial role in Marine ecosystems, since they are main predators of the sea urchins. In the absence of these stars, hedgehogs can devastate sea algae forests, which are essential habitats for many other species.
Therefore, protecting the remaining populations on the coast of Norway, could be fundamental for the recovery of the species and to maintain ecological balance in these regions.
The study also highlights the importance of the unique oceanographic conditions of British Columbia fjords.
These areas, characterized by the entry of fresh water during seasonal thaw, create a warmer surface layer of water and less saline, while the deepest layers remain cold and salinas.
This gradient could be limiting the exposure of sea stars to the conditions that favor the spread of the SSWD.
However, researchers warn that climate change could alter these dynamics, putting populations that currently benefit from these conditions at risk.
Alyssa Gehman, Marine Ecologist from Hakai Institute, told Science News, that anomalously high temperatures have been a recurring factor in SSWD’s shoots. Previous studies have shown that even small changes in temperature can affect the effectiveness of potential pathogens.
Field work also had the collaboration of local indigenous communities, such as Coastal guardians of the first nationswho reported on the presence of large sea stars in their crabs for crab in 2016.
These initial observations led researchers to explore the fjords near Bella Coola, in the territory of the Nuxalk nation, where the existence of these remaining populations was confirmed.
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