When I was down at Pu’uhonua o Hōnaunau National Historical Park recently, I noticed, possibly for the first time, these circles in some of the fishponds. They are the nests of male Mozambique tilapia (Oreochromis mossambicus). The males hope to entice a female into laying her eggs in their nest, after which the male will fertilize them.
Tilapia were introduced to the fishponds to control mosquitoes, but like many such ideas, they have proved detrimental to the well-being of native species. Currently, efforts are underway to remove them from the ponds.
For more information about Pu’uhonua o Hōnaunau National Historical Park, visit https://www.nps.gov/puho/index.htm
Graham's Island 
That’s interesting. Hope they will have success removing them!
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I think the trick will be getting them out without harming thee native species or the pools themselves.
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I agree, not an easy task
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Shame for the fish. They’re just acting naturally.
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It’s not their fault. It’s us smart people who think doing these things is a good idea.
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Well, they are attractive fish, unlike the carp introduced here. We’re still trying to figure out how to eradicate them. But then, nearly all of our livestock was introduced and has caused widespread damage. I can’t see that changing and wonder what our national diet might have been if we’d made different decisions during European settlement. Perhaps the kangaroo would be extinct.
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Humans are, of course, the champion introduced species, moving into new places and irrevocably changing them for better or, more often, worse.
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That was the “smart” idea here as well now they are destroying the number of small fish populations everywhere.
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Funny how many ‘smart ideas’ are the exact opposite.
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I guess you got Cane Toads as well
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Yes we do.
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🙄
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