Saturday , February 27 2021

Formerly abundant sea stars in danger of disease on the west coast



Thousands of sunflower starfish swarm Croker's Rock near Croker Island, left, located in Indian Arm Fjord, north of Vancouver, British Columbia, on October 9, 2013. Three weeks later, in the right photo , the starfish disappeared.
Thousands of sunflower starfish swarm Croker's Rock near Croker Island, left, located in Indian Arm Fjord, north of Vancouver, British Columbia, on October 9, 2013. Three weeks later, in the right photo , the starfish disappeared.

According to a new study conducted by Cornell University in collaboration with the University of California, Davis suggests that the combination of sea heating and an infectious disease debilitates crushed populations of large sunflower sea stars once abundant along the coast west of North America.

Since 2013, the disease of the starfish has achieved an enormous mortality in numerous species of ocean stars, from Mexico to Alaska. The East Coast was not immune, since the disease influenced the coasts of New Jersey to New England.

Drew Harvell, a professor of ecology and evolutionary biology at Cornell, one of the authors of the research, said: "In an abundant time in waters off the coast, the starfish of sunflowers can not now be found on the California coast and are rare in Alaska . The numbers of starfish have remained so low over the last three years, we see them as threatened in the southern part of their range, and we have no data for northern Alaska. "

"Global warming due to a changing atmosphere is probably an important factor. The heat wave in the oceans – a product of rising atmospheric temperatures – is exacerbating starfish disease. It's a lethal disease, and when you add a higher temperature, it kills faster, making a bigger impact. "

"Fisheries rely on nearshore algae forests to form a healthy environment for fish and the wider ocean ecosystem. With the disappearance of sunflower starfish, populations of sea urchins in some areas have exploded, substantially reducing algae. "

Diego Montecino-Latorre, a wildlife epidemiologist at the UC Davis One Health Institute and co-lead author, said that "the starfish continues to decline even in the deepest ocean and is not recovering in the same way as the intertidal Star of the ocher.

"This is likely because this disease has many hosts, and other species that better tolerate the pathogen can spread it to the sunflower star."

Joseph Gaydos, a senior author of the paper and director of the SeaDoc Society program at the University of California at Davis, said, "In California, Washington, and parts of British Columbia, sunflower starfish keep the sea urchins under control. Without the sunflower stars, populations of hedgehogs increase and threaten kelp forests and biodiversity. This cascade effect has a really big impact. "

Between 2006 and 2017, scientists and native scientists trained with the Reef Environmental Education Foundation (REEF) led 10,956 meandering jumping assessments from southern California to Alaska. Before 2013, the jumpers revealed a wealth of starfish, but between 2013 and 2017 the population collapsed.

Researchers at Simon Fraser University and the Hakai Institute have claimed the misfortune of the remote Calvert Island in British Columbia. Ocean warming recorded at REEF sites refers to the expansion of water temperature by up to 4 degrees Celsius, which began in 2014.

NOAA scientists have reviewed starfish from a large number of deepwater trawls from Mexico to the Canadian fringe and recorded a 100% reduction in all states in deep waters of up to 1,000 meters.

For this research, "Disease Epidemic and a Marine Heat Wave are Associated with the Continental Scale Collapse of a Pivotal Predator (Pycnopodia Helianthoides)," the other partner institutions were Simon Fraser University, Stanford University, Hakai Institute and National Oceanic and Atmospheric Administration (NOAA).

The study was published in the journal Science Advances.


Source link