Common Seastar (mostly USA)

Scientific Name:
  Asterias rubens
Family:
   Asteriidae
Usual Size:
to 50 cm, tip of one arm to another, including the central disc.

Habitat:
In British seas, and on the shore when the numbers can reach epidemic proportions, the Common Starfish, Asterias rubens, is the most prevalent conventional starfish of the N.E. Atlantic Ocean. It is an Arctic-Boreal species with a maximum temperature tolerance of about 22° C.
Usually found on the mussel beds offshore. 
Behaviour:
Its principal prey is mussels (consuming them in their shells), but it will eat fish eggs, carrion, and other molluscs.

Starfish consuming a Cockle

Common Starfish eating a mussel
from Southwick Beach 2012

Asterias feeding on a Grey Topshell

Enemies: Common Sunstar, Crossaster papposus.

1 June 2014
At Shell Island, Llanbedr, Gwynedd, North Wales LL45 2PJ. I saw thousands of Asteria rubens washed up on the shore, some dead and some dying. Many were a washed out white and long dead, others were pink/orange and some were purple. Most were of equal size, roughly 10 cm across, though there were a large number half that size. 

20 August 2012 An early morning mussel collecting visit to Kingston Beach on a low spring tide found the unprecedented frequent (30+) occurrence of very small Common Starfish Asterias rubens on the underside of rocks just above Chart Datum. Full Report

14 March 2010
Thousands of Common Starfish, Asterias rubens, were washed up on the strandline on the shingle beach at Budleigh Salterton in south Devon (East Devon AONB). The line of washed up starfish stretched for over a mile.

            Starfish at Budleigh Salterton
         Photograph by Tony Herbert on flickr

9 December 2009
An exceptional mass stranding of millions (a galaxy) of Common Starfish, Asterias rubens, stretched in a broad band for over a quarter of a mile on Holkham Beach on the north coast of Norfolk. 

Their usual residence would be feeding on the mussel beds offshore. From a previous occurrence underneath the chalk cliffs east of Brighton Marina, Sussex, it is my surmise that the mass migration occurs because the Common Starfish have exceeded their food supply offshore. Perhaps, this occurs because of commercial dredging of the mussels. In this case the stranding could have been exacerbated by north-easterly gales. 

26 March 2008
After a recent bout of northerlies in North Wales I took the dog for a walk down on Red Wharf Bay on Anglesey and found all sorts of things washed up. Common Starfish, Asterias rubens,  were very abundant, as a rough guess at 5-10 per square metre, amongst the rest of the wreck.

23 March 2008

17 March 2008
After the storms and the report of a mass stranding of Common Starfish, Asteria rubens, on Brighton Beach, I inspected the strandline on Shoreham Beach. All along the strandline there was a greater number of hundreds of thousands of Slipper Limpets and tens of thousands of Whelk egg balls amongst the usual mixed shell collection including Whelks and Oysters. One Undulate Ray eggcase looked in good condition and was placed in an aquarium in case the embryo was still alive.  There were a few dozen dead Starfish at the Old Fort, but not the hundreds reported from Brighton beach. 

To qualify as nationally newsworthy a Common Starfish stranding must be in tens of thousands. 

Sussex Marine Life Reports

4 -5 March 2008
Hundreds of thousands (perhaps many more) of Common Starfish, Asteria rubens, were washed on the shore of east Kent.
Picture Link

1 January 2007

Common Starfish on the chalk bedrock at Seaford
Photograph by Wednesday Livingstone

22 May 2006
Thousands of dead Common Starfish, Asterias rubens, were seen on the beach at Lydd-on-Sea, Kent. All the starfish were strewn along the high tide line, and for every step I took I passed 20 to 30 dead starfish. I walked about half a mile along the beach and the line of dead starfish seemed never ending in both directions. Some of the starfish were laying on the sand and in the sand pools but these too were dead. Also, about 30 Sea Mice, (an annelid worm), Aphrodite aculeata, were found washed up dead.
NB: This discovery followed two days of gales. 

28 January 2006
Thousands of dead specimens of the Common Starfish, Asterias rubens, were washed up on the beach about a mile and a half to the north of Tywyn on the Cardigan Bay coast of north Wales.  There seem to be various interpretations of these mass strandings, including winter storms and changes in water temperature.

17 March 2002
Thousands of Common Starfish, Asterias rubens, were washed up on the beach at Holkham, Norfolk, on the east coast of England after sustained north-easterly gales. 

31 December 2001
Thousands of Common Starfish, Asterias rubens, are discovered washed up dead on the shore at Formby, Merseyside, Lancashire.