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Author Topic: Why the sudden influx of starfish?  (Read 7199 times)

Offline thedoc

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Why the sudden influx of starfish?
« on: 29/04/2012 11:53:01 »
Catherinecoates@blueyonder.co.uk asked the Naked Scientists:
   
Hi there,

Please can u help iam currently on holiday in east Sussex at pevensey bay, the beach is covered in starfish they are varying in size from 5" across to some really large ones about 12" across, I have been coming here for 40 yrs and never seen anything like this I have taken some photos not sure how to attach them to this email as its from my iphone am hoping you can help answer my query.

Thank you

Kate Coates

What do you think?
« Last Edit: 29/04/2012 11:53:01 by _system »


 

Offline Don_1

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Re: Why the sudden influx of starfish?
« Reply #1 on: 06/05/2012 01:32:15 »
The chances are you are seeing Asterias rubens, the Common Starfish. These North Atlantic starfish are present in huge numbers around the British coast. Their population can be boosted given the right conditions, such calm seas, slightly increased sea temperatures, good food supply and lower predation of the larvae. Over fishing of plankton feeders such as Herring would give the young a better chance of survival, so the following year, there would be greater numbers of mature starfish to breed. Such a population explosion would probably occur over a two year period. Breeding time is in the spring, and if there is a good food supply, the Asterias rubens can grow quite quickly.

Why are there so many beached? It is not uncommon to find huge numbers beached after stormy weather. Other south coast beaches have experienced this in the past. Brighton, Shoreham, Seaford and huge numbers have also been record at Holkham on the Norfolk coast, Anglesey and Cardigan Bay on the Welsh coast line, Formby on Merseyside, Lydd on the Kent coast and many more.

These beachings are in fact so common, that they don't usually get reported unless there are well into the 10's of thousands.
 

Offline CliffordK

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Re: Why the sudden influx of starfish?
« Reply #2 on: 06/05/2012 01:54:16 »
This is from 2009, but it is perhaps related.

The starfish, which washed up early last week, may have been victims of dredgers scraping the seabeds for mussels, their favourite food. The process could have dislodged the feeding starfish and the currents carried them to the shore.

But Nigel Croasdale, of the Hunstanton Sea Life Sanctuary, believes Mother Nature is the most likely culprit.

He said: 'Strandings tend to occur once a year or once every two years.

'They are also most common between November and March - the time of the year when we experience bigger tides.'



I've only seen starfish firmly attached to rocks near the level of the surf, never free floating in the sea.  However, notes I'm seeing indicate that they are often found as bottom dwellers.
 

Offline Don_1

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Re: Why the sudden influx of starfish?
« Reply #3 on: 06/05/2012 02:15:31 »
Hunstanton is another Norfolk coast beach, right on the mouth of The Wash.

The British Marine Life Study Society has a list of recorded beachings here.


Just looking at the list, I see the Holkham and Hunstanton beachings are one in the same.
« Last Edit: 06/05/2012 02:19:43 by Don_1 »
 

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Re: Why the sudden influx of starfish?
« Reply #3 on: 06/05/2012 02:15:31 »

 

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