Tag Archives: Sea Star

The wasting of the stars: A look into the largest ocean epidemic in recorded history

By Peter Arcuni
July 18, 2017
Originally published in Peninsula Press
Audio report

In June 2013, Steve Fradkin hiked the rugged coast of Washington State’s Olympic National Park to count the stars. In the summertime, the lowest tides expose the slippery rocks of the intertidal zone from daybreak until noon. Perfect conditions for spotting Pisaster ochraceus, the five-armed purple, orange and red sea stars common to Pacific waters along the western edge of the United States. Continue reading The wasting of the stars: A look into the largest ocean epidemic in recorded history

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Sea Star Loss From Our Coast Might Be Mussels Gain


By Jay T. Cullen

Note that the video above was shot on May 8, 2015, set to Debussy’s Clair de Lune, by the YouTube user NorthOlbo who makes wonderful pieces about the British Columbian coast. Check him out.

The purpose of this more visual post is to report on a recent trip my students and I took to a local beach and what we saw there. Botanical Beach is renowned for its tide pools and part of the Juan de Fuca Provincial Park here on the southwest coast of Vancouver Island, British Columbia Canada. There are strange conditions currently in the northeast Pacific from the “blob” of warm water related to anomalous winter mixing in 2013-2014 to the widespread disappearance of sea stars owing to wasting disease after infection by virus. Some link these changes in the marine ecosystem to the very low levels of Fukushima derived radioisotope contamination present offshore and recently detected at the shoreline although there is little evidence to support such views nor are such impacts very likely. There is indeed life abundant at Botanical Beach but it is changing. The sea star is a keystone predator whose removal has consequences. The most obvious of these on visiting the beach again was the predominance of California mussels to be found. More about our adventure below the fold. Continue reading Sea Star Loss From Our Coast Might Be Mussels Gain

Study Identifies Pathogen Responsible For Sea Star Mass Die Offs Along Pacific Coast

By Jay T. Cullen

Sea star with Sea Star Wasting Disease photographed by the author at Botanical Beach near Port Renfrew BC in July 2014.

This diary summarizes a newly published paper by Hewson and colleagues in Proceedings of the National Academy of Sciences of the USA which investigated the cause of sea star die offs along the west coast of North America. This diary is part of series dedicated to summarizing scientific research on the impact of the triple meltdowns at the Fukushima Dai-ichii nuclear power plant on the North Pacific Ocean and the health of residents of North America. Northeast Pacific sea stars have experienced a mass die off recently and have disappeared from certain coastal ecosystems as a result. The Hewson et al. paper presents evidence that the cause of the wasting disease can be transmitted between affected to healthy individuals. The disease-carrying agent is virus sized and likely sea star-associated densovirus (SSaDV) which is found in greater numbers in diseased versus healthy sea stars. They also detected SSaDV in museum specimens of sea star dating from 1942 indicating that the virus has had a long term presence along the North American west coast.


There have been many speculative news items which have linked the release of radionuclides from Fukushima to the North Pacific Ocean to the most recent outbreak of sea star wasting which is occurring in west coast intertidal habitats. This is despite the fact that, for example, Fukushima derived radionuclides have still yet to be detected in coastal seawater collected up and down the North American Pacific coast.

Beginning in June 2013 massive numbers of sea stars have succumbed to sea-star wasting disease (SSWD) whereby they rapidly deteriorate, losing limbs, and turn into piles of slime. SSWD is an old term used to describe similar outbreaks of wasting that have occurred since at least 1979. The geographic extent and number of species impacted by the current SSWD outbreak is unprecedented. Affected individuals present with behavioural changes, lethargy, deflation, limb curling and loss, lesions and death. Very few individuals with symptoms are observed to recover.

Photographs of SSWD-affected stars (A) asymptomatic P. helianthoides, (B) symptomatic P. helianthoides, and (C) symptomatic P. ochraceus. Disease symptoms are consistent with loss of turgor, loss of rays, formation of lesions, and animal decomposition. (D) Map showing occurrence of SSWD based on first reported observation. (E) Transmission electron micrograph of negatively stained (uranyl acetate) viruses extracted from an affected wild E. troschelii from Vancouver . The sample contained 20–25-nm diameter nonenveloped icosohedral viral particles on a background of cellular debris (primarily ribosomal subunits) and degraded viral particles of similar morphology.

Hewson and colleagues examined affected and asymptomatic sea stars to demonstrate that an infective agent was responsible for SSWD. To do this they took homogenized SSWD affected sea stars and administered an inoculate or a heat killed inoculate of virus size containing filtrate to tanks containing healthy individuals. Results of these experiments indicate that heat killed inoculates did not lead healthy individuals to develop SSWD while inoculates with potentially live viral particles lead to SSWD symptoms in the previously healthy population. Previously healthy sea stars had very low loads of a virus callled Sea Star-Associated Densovirus (SSaDV) while after developing symptoms much higher amounts of SSaDV were found in the sea stars.

(A) Proportion of stars remaining asymptomatic after inoculation with control (heat-killed) or virus-sized fraction (VSF) of asteroid homogenates in first (Expt 1) and second (Expt 2) challenge. (B) Change in SSaDV load between initiation of viral challenge and termination of experiment (i.e., animal expiry in live challenge or euthanasia of control animals). Note difference in scale.
The authors then looked for the virus in asymptomatic and SSWD affected individuals in the wild finding that affected individuals were about 3 times more likely to be virus carrying than asymptomatic individuals. The virus was also found in plankton, sediments and other echinoderms. The presence of the virus in plankton and in filtration media of public aquaria affected by SSWD is consistent with observations that the disease could spread through ocean currents between infected and uninfected areas of the coast.

The authors conclude by pointing out that the spread of SSWD along our coast is most consistent with an infectious agent. Based on their observations and laboratory experiments this agent is most likely SSaDV which has been present along the coast for at least 72 years. Fukushima in not mentioned once in the article as there is no scientific evidence to relate SSWD to the trace concentrations of Fukushima derived radionuclides present offshore.

The authors identify outstanding questions as follows:

How exactly (by what mechanism) does SSaDV kill sea stars?
Are there other microbial agents involved in the wasting/death process?
What triggers outbreaks of SSWD?
How will the absence of important predators like sea stars affect the marine ecosystem along our coast?

The study highlights the increasingly recognized importance of marine viruses in helping to shape community structure and ecosystem dynamics in the ocean.

What is Causing Sea Star Wasting Syndrome?

What is causing the outbreak?

Original article by Naomi Klouda of the Homer Tribune here

Scientists studying the most recent outbreak of sea star wasting syndrome along the Pacific west coast have ruled out plastics, ocean acidification and radioactivity sourced from Fukushima as likely causes of the die off.  Scientists working on the problem include Pete Raimondi of the Department of Ecology and Evolutionary Biology at University of California, Santa Cruz, and Benjamin Miner, professor of marine biology at Western Washington University, who discussed their most recent work in a National Public Radio Forum. A link to the most up to date map showing the geographic extent of the outbreak can be viewed by clicking here.  The most likely cause appears to be a pathogen/infection that is transmitted through the water and distributed by currents up and down the coast. At present there is no definitive answer as to the cause of the outbreak.

 

Citizen Scientists Should Get Involved

If you are interested in helping the scientific community document the presence of sea star wasting syndrome please visit the following University of California Santa Cruz website.  Another great resource to learn more about the outbreak can be found on Karyn Traphagen’s website that provides fine photos and information.

Sea Star showing signs of wasting syndrome photographed by the author at Botanical Beach near Port Renfrew, BC in July 2014
Sea Star showing signs of wasting syndrome photographed by the author at Botanical Beach near Port Renfrew, BC in July 2014