Sea stars, also known as starfish, play an important role in the ecosystem of the Salish Sea. The PNW is home to several species of these interesting animals. They are considered to be keystone species, which means that their presence has a significant impact on the overall structure and function of the ecosystem.
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Sea stars are known to help maintain diversity within the ecosystem. They are top predators and help to keep populations of other species in balance, particularly those of mussels and sea urchins. Without sea stars, these populations can grow unchecked, leading to changes in the ecosystem. By consuming certain species, they can create space and resources for other species to thrive. For example, if a particular species of bivalve were to become too abundant, it could outcompete other bivalves and prevent them from surviving. By feeding on this species, sea stars can help to create space for other bivalves to establish themselves in the ecosystem.
In addition to their role as predators, sea stars can also help to maintain the health of the ecosystem by serving as indicators of environmental conditions. Because they are sensitive to changes in water temperature and other factors, they can be used as a tool for monitoring the health of the ecosystem and identifying potential issues before they become more widespread.
Each species plays an important role in the ecosystem, helping to keep populations of other animals in check, and serving as prey for larger predators. Some of the most commonly found species of sea stars in the Salish Sea include:
Sunflower Star (Pycnopodia helianthoides): This species is known for its large size, with arms that can grow up to a meter long. It is orange or red in color and has numerous small tube feet.
Ochre Star (Pisaster ochraceus): This sea star is commonly found on rocky shores and tide pools, and is known for its purplish-brown color and five arms. It feeds on mussels and barnacles, using its many tube feet to pry open the shells.
Leather Star (Dermasterias imbricata): This species is found in deeper waters, and has a distinctive leathery texture to its skin. It is usually green or brown in color and can grow up to 20 centimeters in diameter.
Six-rayed Star (Leptasterias hexactis): This species is commonly found in the colder waters of the Salish Sea, and is known for its six arms that are arranged in a hexagonal pattern. It is usually brown or yellow in color and feeds on plankton.
Starfish Wasting Disease
Recent years have seen a declining population of these interesting creatures in our Salish Sea waters. Starfish wasting disease is a condition that affects several species of sea stars. The disease causes the sea stars to develop lesions and then lose their limbs, ultimately leading to death. The disease has been observed in the Pacific Northwest since 2013 and has resulted in significant declines in sea star populations in the region.
The exact cause of starfish wasting disease is not fully understood, but researchers believe that it is caused by a virus or bacteria that affects the sea stars’ immune system. The disease is thought to be spread through the water, but it is not clear how it is introduced to the sea star populations. The impact of starfish wasting disease on the Pacific Northwest ecosystem has been significant. Overall, the long-term effects of the disease on the Pacific Northwest ecosystem are still not fully understood, and research on the disease and its impact are ongoing.