Crab Attack and Dying Seaweed

 

 

April 22nd and the Kelp growing in the lower intertidal at Constellation Marine Reserve is already dying.  Brown seaweeds do not tolerate the hot sun and bright sunlight.  So if you are a Kelp you want to attach to something that will keep you in deeper water and not allow you to be exposed to the harsh elements......that is if you want to stay alive.

Some images attached of dying seaweeds and also an image and short video of a Red Rock Crab attacking and eating a Northern Kelp Crab......what with the harsh elements and hungry predators it's a wonder anything survives.   :)

 

Dying Witches' Hair seaweed



Dying Kelp

Dying Kelp

Dying Kelp

Red Rock Crab eating Northern Kelp Crab
 

Red Rock Crab eating Northern Kelp Crab




 

 



Sea Star Wasting Disease Update

 

 

 

A survey of Constellation Marine Reserve in West Seattle on April 20th 2015 results:

 

Pisaster ochraceus (Purple Sea Star)   41 healthy - 5 with SSWD

Pycnopodia helianthoides  (Sunflower Star)   1 small (damaged likely by gull) otherwise healthy

Evasterias troschelii (Mottled Star) None observed

No other sea stars observed.

 

Tide Level:   minus 1.7ft  at 12:45PM

Surface temp:   63 deg f.

Wind - N, light

Clear and sunny

The count included all of Constellation Marine Reserve down to the minus 1.7ft tide level.

 

Much of the beach was covered with an extensive growth of seaweeds, especially Wire Weed and various kelps.  So some sea stars may not have been visible.  The survey only included sea stars that were easily visible without turning over seaweeds or rocks.  Previous surveys have been done in the same manner.  Last year appeared to be a good year for sea star recruitment and many were seen over the Winter and most appeared healthy.  In Spring the juvenile stars go into hiding under rocks and crevasses where they cannot be seen so it is difficult to access the population of juvenile stars during the Spring and Summer.  The question is:  Will these juvenile stars remain healthy or contract SSWD?  We will likely not know the full answer to that for a few years.  All of the Purple Stars observed on April 20th were medium to large size as in the images.

 

The highest count of Pisaster ochraceus  at Constellation Marine Reserve was in August of 2011   -  609  (prior to SSWD). 

 

Sunflower Star (small) with damage (likely due to gull)

Purple Sea Star with SSWD

Purple Sea Star (healthy appearing)