Pete Giwojna
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Re:Hippocampus erectus depigmentation - 2009/06/22 23:54
Dear Fisher:
Very interesting!
No, sir -- the phenomenon you describe is beyond my experience with seahorses. I am aware of no disease processes that can selectively destroy melanophores and render a seahorse unable to produce melanin, certainly none that affect only males. And as you said, that would have to be some sort of a recessive genetic trait if it is occurring naturally at a certain stage of the seahorse's development, absent any sort of an underlying disease. I have never seen an albino seahorse in all my years...
Of course, suspicious white patches and localized areas of depigmentation are often an early indication of incipient bacterial infections and certain parasites such as Costia or Uronema. But in such cases the white patches typically develop into open sores and ulceration, rather than spreading out and affecting more and more of the seahorse's body with a pigmented areas. And these skin infections naturally have an adverse affect on the health of the affected individuals...
For example, sir, here are some photographs of seahorses with suspicious white patches that are the result of diseases. In the first two pictures below we see discrete white oblong markings on the tails of seahorses which are due to bacterial lesions:
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In the following picture, the pale white patches seen on this Hippocampus kuda are the result of a parasitic skin infection caused by flagellates (Costia sp.) with secondary bacterial infection:
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And in the following photograph, the white saddles and blotches on the yellow seahorse on the left are normal markings, but the white patch on the flank of the dark-colored seahorse on the right is due to marine ulcer disease (vibriosis) and you can already see some tissue erosion occurring at the site of the bacterial lesion:
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The closest thing to what you are describing would be the occasional specimens of Hippocampus erectus that develop a piebald color pattern, in which snow white areas occur against a darker background coloration. The most striking aspect about their color pattern is the brilliant contrast between the light and dark areas. That eye-catching mottled pattern is completely random, so much so that no two specimens are exactly alike, and the extent of the mottling varies greatly from individual to individual. White and brown are the most commonly seen colors when this piebald pattern develops, but I have also seen specimens that were white and black, white and yellow, and gray and yellow. Interestingly, it most seahorses I have seen with this Pinto-like color pattern, the head of the seahorse is almost always dark colored.
Here are some photographs of healthy seahorses with the attractive piebald color pattern. The following for photographs were taken by Dr. Clyde Tamaru:
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And here is another very healthy, beautiful yellow and white Pinto:
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Photo by Leslie Leddo
I will forward your e-mail to Carol and Craig, the owners/operators of the Ocean Rider aquaculture facility, so they can contact you if they are interested in seeing your photographs or presenting your material to the staff veterinarian.
And I would very much like to see the photographs documenting the depigmentation and loss of coloration you describe. If you can send the link to your photographs to my e-mail address (PeteGiwojna@aol.com), I will be happy to examine the material more closely.
Best of luck with your amelanistic seahorses, Fisher! Please keep us posted if you find out anything more; I am very interested in hearing about any further developments along those lines.
Respectfully,
Pete Giwojna
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