macrofauna sorting

Les Watling watling at
Fri Jul 27 18:30:56 EST 2001

My sincerest thanks to all who answered my request about using Ludox, 
etc., for macrofauna sorting.  I've been working with benthic samples for 
many years and thought perhaps I was behind the times with respect to 
our methods.  From the comments forwarded to me it seems as though 
there is still no easy way to deal with grab samples taken in sand and 
gravel substrates.  With one exception, there was a general feeling that 
Ludox was not the answer for larger organisms, although a couple of 
people have used it to retrieve smaller worms and crustaceans.  It seems 
that the most satisfactory solution was to run water into the sample and let 
the lighter materials float onto a fine mesh screen.  A quick post-float 
examination is then used to retrieve larger organisms.  We have done 
this with dredge samples, but have not used the technique with 
quantitative samples.  Still, it seems that it might be as accurate as long 
times spent picking.  One person suggested looking into industrial 
separation technologies, which I think we will do, but most probably those 
methods will wind up being expensive, or as in the case of 
trichloroethylene or carbon tetrachloride, have rather high costs to the 
health of the sample processors. 

All the best, Les.  

Les Watling
Professor of Oceanography and
Pew Fellow in Marine Conservation
Darling Marine Center
University of Maine
Walpole, ME 04573

Phone 207-563-3146 x248
Fax  207-563-3119
<watling at>

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