Massive starfish die-off in Pacific Ocean linked to mystery virus

[chillyinCanada]

My understanding is that there was an increase in starfish population/overabundance. The virus more easily spread. Mother Nature taking care of keeping things in balance?

 

[drbill]

Certainly the spread of this virus would be enhanced by over-population in sea stars. I just don't have the data that shows an over-populated state (at least not down here in SoCal).

Back in the late 1990s we had a situation where our endemic island fox population had reached fairly high numbers... then canine distemper virus (transmitted from dogs) spread through the population like wildfire. Fortunately we caught it in time (I was V.P. of the Catalina Conservancy which owns 88% of the island) and initiated a rapid response fox captive breeding program that resulted in the most rapid recovery of an endangered species known.

Of course a "captive breeding program" for sea stars would probably not be effective (unless maybe these are the sea stars mentioned previously that live "on land").

 

[descent]

If it is global climate change, I would be a bit surprised since the epidemic covered a very wide range of latitudes from the Pacific NW into Mexico. However one does need to wonder why this virus suddenly took off so explosively and extensively.

Higher water temperatures are likely responsible in some way. This summer, we all marveled at the elevated surface temperatures in Monterey. On the warmest days, I could easily have left my hood at home.

The article in Smithsonian Mag (thank you, 3D diver!) does not speculate beyond what is contained in the PNAS published paper. Any possible vectors or amplifications are for the reader to guess.

There is a ciliate protozoan, Orchitophrya stellarum, with an unpleasant attack. It is a spermatophage, a parasite of echinoderm reproductive ducts. Its activity and effectiveness increase as the temperature rises.

Critically, the starfish immune response seems to be much less effective at higher temperatures.

Is it possible that there is a crossover point of viral lethality? Where warmer water makes an aggressive protozoan parasite much more effective while (perhaps) carrying in an opportunistic cargo of densovirii, who then find a starfish immune system weakened by warmer water?

---------- Post added November 24th, 2014 at 02:19 AM ----------

Certainly the spread of this virus would be enhanced by over-population in sea stars. ...

There was a really interesting article in the Seattle Times earlier this year that discussed populations. Many Puget Sound marine scientists got interviewed for this piece.


Starfish are ‘just melting’: Disease killing 80 percent of them

By Lynda V. Mapes
Seattle Times staff reporter
Originally published June 28, 2014 at 8:00 PM | Page modified June 30, 2014 at 12:40 PM

A mysterious wasting syndrome is wiping out sea stars along the entire West Coast, with a new flareup in Washington hitting hard this month and walloping Oregon waters previously unaffected. ...

Populations of sea star were so dense he says he was not surprised to see a correction. “We went for a good decade with incredible overpopulation, the crowding was incredible,” [said Jeffrey Marliave, vice president of marine science at the Vancouver Aquarium]. “I’ll confess at first I was thinking, ‘Hallelujah, something finally is controlling them.’ But this is a little overboard, it is scary how badly things are going.”

 

[jwin]

SHOCKING Photos! "Pacific Ocean Now Dead From Fukushima Radiation": https://youtu.be/F_CPQUKOg_Q url]

A virus? OK!
What's killing everything else?

John

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