I am not aware of any such studies, although I would be interested in the reasons on why would that be done. As far as I understand, testosterone functions in the same way in both type of fish (ie elasmobranches and osteichties). Despite that, why would you want to compare those levels? Are you under the impression they are going to be similar (I would assume they are quite different)? If so, why? I can point you out to a colleague of mine working on reproductive physiology in silversides if you wish to ask him about this.

Juan:

Thanks for commenting on my question at large. The testerone levels can help determine the aggresiveness of animals. For example the bull shark has shown to have higher testerone levels than most of the other selachians. My research is centered around the common characteristics of sharks and catfish of which there are several. I would be quite appreciative to directed to your colleague. The levels of each type of fish is the interesting point as the functionality would be about the same.

I have a simple synopsis of my research so far as it is consistently evolving that I could send to you if you would like to read it. Just let me know.

Thanks again for your input

I need contact information to give him a way of contacting you James.

No worries, I found you can share questions through facebook.

Or you can e-mail me at [email protected]

Thanks

I've given my colleague the email, he should be in contact with you soon, cheers.

Thank you for directing me to your colleague.

James

None that I know of.

awesome to hear from you Dr. Baskin.