IUBio

Sampling beachworms

Matthew O'Brien MObrien at zoology.uq.edu.au
Mon May 10 20:39:12 EST 1999


Hi everyone,

For my PhD I'm working on some large beachworms (.3 - 1.5 meter) and have
to work out some kind of replicatable sampling strategy to work out
population size, density etc.  They live in the subtidal to swash zones on
sandy surf beaches, and i'm working on the east coast of Australia, around
Brisbane. 

Because of their size and mobility, standard cores won't work.  While
taking a front end loader onto the beach and scooping up the beach and
sifting it would work, somehow it doesn't seem feasible!!  The only method
I have seen to actually measure abundance/population size/density has been
to attract the worms to the surface using burley (oily shark skin) and
count the number of emerged worms.  

There are a couple of problems with this method:  It's hard to distiguish
the different species. It assumes 100% emergence.  It assumes all the worms
emerge at the one point in time (and stay emerged long enough to count).

Commercial worm fishermen catch the worms by hand (i.e. Once emerged, are
pulled out by hand)  I can look at fishermens catches, times fished etc,
however the fishermen are selective for larger worms, and particular
species.  Again the same problems apply.

One idea i am playing with at the moment is using photography to document
emergence, and then the counting thing won't be a problem and maybe (i
haven't got my hopes up) i can work out species as well.

If anyone has any great references/ideas/methods/comments for sampling
these critters (or even anything like them!), can you  please PLEASE reply.
 If you don't have answers, but have ideas please tell me!  

I REALLY NEED AND WOULD APPRECIATE SOME FEEDBACK ON THIS!

Thanks in advance and happy worming!

Matthew

_____________________________________________________
Matthew O'Brien,
Department of Zoology and Entomology,
University of Queensland,
Brisbane  QLD  4072

email: mobrien at zoology.uq.edu.au
Fax:  (07) 3365 1655
Ph:   (07) 3365 2491 (Zoology Office) 


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