Richard,
a former colleague of mine, Kurt Kotrschal did several work on this
problem. You may contact him via:
[log in to unmask]

With best wishes
Robert

Date:         Thu, 15 Jun 2000 09:39:16 +0100
  Reply-To:     Scientific forum on fish and fisheries
<[log in to unmask]>
  Sender:       Scientific forum on fish and fisheries
<[log in to unmask]>
  From:         Richard Lord <[log in to unmask]>
  Subject:      Gaidropsarus D1 oscillating wave
  Comments: cc: Andy Horton <[log in to unmask]>
  Content-Type: text/plain; charset="us-ascii"

  A commercial fisherman brought me a shore rockling, Gaidropsarus
mediterraneus, and a three bearded rockling, Gaidropsarus vulgaris, last
night for a school class I am teaching.  The Gaidropsarus rocklings, and
possibly others, have a low first dorsal fin that constantly oscillates
rapidly in a wave along its length.  The first dorsal fin is so low that it
is difficult to see so the fin gives the impression that it is a pulsing
'light' travelling down the back of a fish.  Has someone studied this
phenomenon? Does this fin serve a useful function for the fish?  Do other
subfamilies of fishes also display this characteristic?

  The fisherman told me that at certain times of year he noticed that some
three bearded rocklings have a bright orange spot on their body. He wonders
if this is a sexual character and whether the species can be sexed using
this character.

  Yours sincerely,
  Richard
  Richard Lord
  Guernsey GY1 1BQ
  Great Britain

  Email:  [log in to unmask]
  Tel: +44 (0)1481 700688
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************************************************************************
  Dr. Robert A. Patzner                     [log in to unmask]
  Institute of Zoology
  University of Salzburg
  Hellbrunnerstrasse 34                    Tel.:
++43-662-8044-5619
  A-5020 Salzburg                           Fax.: ++43-662-8044-5698
  Austria                                                  or  -662-6389811
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