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Sea stars, a keystone species and alpha predator in the
oceans circle of life, are in danger. There have been large mortality events in
sea star populations in the past, and it seems it may be happening again. The sea
stars' food, mussels, multiply without being eaten, changing the habitat if sea
stars were to leave. This danger to the sea stars is called Sea Star Wasting
Disease (SSWD), and it is an epidemic. It is very difficult, if not impossible,
to filter out of water. The disease is viral, not being filtered by a 0.22 µm
filter. At least 20 species of sea stars are affected by the disease, and high mortality
has been experienced in the United States west coast. Several locations in
southeast Alaska, Western Prince William Sound, and Kachemak Bay have
experienced the disease. Stars often lose arms when infected and die within a
few days of exhibiting symptoms.
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Figure 2: Sites that were surveyed in Prince William
Sound (1) and National Parks that border the Northern Gulf of Alaska (1),
Kachemak Bay (2), and the Western Aleutian Islands (3).
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The National Park Service, U.S. Geological Survey, UAF,
NOAA, and GulfWatch Alaska began looking for the disease together in 2014, in
southcentral Alaska. Researchers searched for the disease both in long-term
monitoring sites and outside the boundaries of the long-term monitoring, in the
Western Aleutian Islands.
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| Figure 3: GulfWatch Alaska long-term monitoring sites. Kenai Fjords NP surveyed in 2014, Prince William Sound surveyed in 2015 |
Nine of 1,588 sea stars across 30 sites were found to be
infected with SSWD in 2014. All nine were found in Kenai Fjords National Park.
In 2015, 69 of 2,016 observed sea stars had the disease. Almost all were found
in Kachemak Bay. In Prince William Sound, 2 of 884 had the disease, also in
2015. Only 2 sea stars were found exhibiting the disease in the Western Aleutian
Islands. Even with the small prevalence increase in 2015, diseased star occurrence
is still low compared to the lower 48 and southeast Alaska. More information is
needed to determine why Kachemak Bay harbored the most sea stars exhibiting the
disease.
https://www.nps.gov/articles/sea-star-wasting-disease.htm
And for another blog post on this disease, you can visit this page.
And for another blog post on this disease, you can visit this page.
This is an interesting post. Seeing that Sea start can die within days of exhibiting the symptoms I was curious as to what the symptoms were. I found that the first symptom is normally white lesions found on the star fish. The next symptom is decaying around the lesions. After this happens the water vascular system of the start fish fails causing it to become limp. Stretching than occurs at the arms and than they fall off.
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