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Hi John,
Has anyone ever prepared histological sections of the filaments to see if they
have sensory organs on them? It is difficult to imagine a hydrodynamic function
for them but Karel Leim at Harvard may have some ideas. His finding that tarpons
can respire are taken into their air bladders was an eye opener to me. Some
years ago I contacted Univ. of Washington SeaGrant and Univ. of Washington Press
about reprinting Marine Fish Larvae because many people had asked me about its
availability. I just checked Amazon.com's used book link and saw two copies
advertised for $53 each. Unbelievable.
Best wishes,
Geoff
Jon Shenker wrote:
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>
> An off-the-wall question:
>
> Does anyone have any good hypotheses about the function of the elongated
> dorsal filaments that are found in some fish species?
>
> In the lower teleosts:
> Tarpon have very long filaments, ladyfish don't.
> Shafted bonefish (Albula nemoptera) has the dorsal filament, bonefish (A.
> vulpes) don't.
> Three or four North American clupeids have filaments, the rest don't.
>
> In the elasmobranchs, many species have some sort of elongation of the
> dorsal fin beyond the fin base, but the fin seems elongated into distinct
> filaments in hammerhead, bonnetheads and others.
>
> A hydrodynamic function? Maybe in elasmos, who have larger, stiffer
> filaments, but in the slender , flexible filaments of teleosts?
> Why would some closely-related species have them, and others not?
>
> Would removing a portion of the dorsal filament of a tarpon (for DNA
> analysis) have an impact on the fish?
>
> Any information or speculation would be welcome.
>
> On another note: My old copy of Reuben Lasker's (ed.) Marine Fish Larvae
> has finally been shredded beyond repair before I found time to photocopy it.
> It's an oldie but a goodie for helping students get started in the larval
> fish field. I haven't had any luck finding a copy for sale in the used book
> web sites. If anyone sees a copy for sale, please let me know.
>
> Thanks.
>
> Jon Shenker, Ph.D.
> Associate Professor of Marine Biology and Aquaculture
> Department of Biological Sciences
> Florida Institute of Technology
> 150 West University Boulevard
> Melbourne, FL 32901
> 321-674-8145
> FAX 321-674-7238
> [log in to unmask]
>
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