Ben Richards' request, collector for small inverts:

[Kerry Clark]

>>Along the same lines, we are also wishing to construct a "slurp
gun" for "sucking" small fishes and invertebrates from the water column.
Any design pointers on these would be much appreciated as well.  Thanks in
advance.

Ben,
    My experience with "slurp guns" has not been good (my grad students and
I sometimes hang around dive shops and snicker whenever the Florida
tourists buy one), but you might be interested in my design for something a
colleague christened the "Clarksucker" (he requested that I _not_ reveal
his name, but he is a prominent authority on brittle stars).   Basically,
it uses a Nalgene wash bottle and two valves from polyethylene gas siphons
(K-Mart: $1.99 ea) to yield a flow-through suction collector, which very
gently, but firmly,  pulls in small inverts.  It probably won't work on
fish, except for larvae, as they swim too strongly.  But it has
revolutionized research on sea slugs, and I use it for many other small
marine invertebrates, too. It works flawlessly. The original citation is:
       1971. K.B. Clark. Construction of a collecting device for small
aquatic organisms and a method for the rapid weighing of small
invertebrates. Veliger 13:363-367.  Sorry, I'm out of reprints.
      The walls of the bottle are compressed by hand and then spring back,
pulling in a vortex of water that sucks the animal into the bottle.  A
small piece of Nytex screen makes sure that the little snots stay in the
bottle.  I can collect up to about a hundred slugs before things start to
plug up.  The animals are  retrieved in excellent physiological condition,
because each "slurp" refreshes the water in the bottle. An indication of
this is that sea slugs lose none of their cerata, which are easily knocked
off and are quickly shed under physiological stress.
   I have made a number of improvements through the years; the major one is
to use a hot-glue gun with  polyethylene sticks to weld the parts together;
in the original paper, I used wallboard adhesive to hold the plastic
together, which wasn't permanent enough.  If you want to send me a 500 ml
Nalgene wide-mouth wash bottle and $5.00, I'll assemble one for you (sorry,
caller #1 only--assembly takes an hour), and you can copy the design for
additional suckers.  Ideal for things like siphonophores, small medusae,
etc. -- as long as they'll fit through a 1/4" (6mm) orifice
(cross-section--length is irrelevant).
   I'm planning to post instructions for the new model--the "Mark XIV" --
on my website sometime this summer. I'll post a notice to this list at that
time.





- -
Kerry Bruce Clark, F.A.A.A.S.,  Professor of Biological Sciences
Florida Institute of Technology, Melbourne, FL 32901-6988
Phone 1-407-768-8000 x8195
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