Sea-star wasting is still at work in the sub-tidal environment of the central Strait of Juan de Fuca

A map showing most of our long-term sub-tidal monitoring sites around the Elwha River Delta.  We've got a few additional sites closer to Freshwater Bay, and Green Point.

I was able to join up again this summer with a team of divers from the US Geological Survey and Lower Elwha Klallam Tribe to collect sub-tidal ecology data at a series of sites along the central Strait of Juan de Fuca.  We are basically limping along a program that we started way back in 2008, that at the time was focused solely on understanding how dam removal would influence the coastal marine ecological community near the Elwha River mouth.  We published our opus on that question in 2017.  Since 2017, though, we've continued each summer to cobble together just enough support to visit at least some of our sites.

Nancy Elder (diver in far field) and Steve Rubin (diver in near field) from the US Geological Survey survey a transect at site E2 on 6 August 2019

Our focus has broadened a bit, now, and we are developing an expanded set of goals for this work:

1. Continue to try to understand how habitats that were altered by dam removal evolve over longer-time-scales
2. Use some of our sites that were less altered by dam removal to understand overall trends in ecological conditions, and patterns of annual variability
3. Understand patterns and trends related to loss and recovery of sea stars due to Sea Star Wasting Syndrome (SSWS)

Its #3 that I want to focus on briefly here, because SSWS is still at work in these sub-tidal environments of the Strait of Juan de Fuca.  How do we know?  We saw it:

The arm of a Pycopodia helianthoides on the sea-floor at Site GP1 on 25 July 2019.  Wasting probably proceeds very quickly, so it is likely that this star was probably roaming the sea-floor looking healthy just the day before. 

We did see a few other healthy-looking P. helianthoides across the sites that we visited. This star, for example, was at the same site on the same day:

One of the larger stars we observed at our sites this summer...maybe a bit in excess of 30cm.  Site GP1, 25 July 2019.

But clearly their numbers are still very depressed from what we used to see prior to the onset of disease in 2014.  In 2008, for example, P. helianthoides was the 5th most abundant invertebrate at our sites (see p. 148 here).

The star in the photo above was also notable for its relatively large size.  In general, most of the P. helianthoides that we've observed at these sites since 2014 have been less than 30 cm in diameter, whereas in the past we regularly observed larger specimens:

A large star catching a ride on the back of Steve Rubin, USGS, at a site near Freshwater Bay, 9 September 2009.

To end on a hopeful note - I did recently observe some larger specimens at a site in Port Angeles harbor this year...the first I've seen in "the wild" since 2014.  Maybe the subject of a future post.