It turns out that each of the three populations had very distinct mitochondrial DNA, which suggests that very little interbreeding has occurred between the populations. Another study showed a similar result. Bluehead wrasses that live on reefs near St. Croix are also homebodies. The bony structure incorporates trace elements from every place a fish has lived throughout its life. These results, and others, turn previous ideas topsy-turvy.
Biologists can no longer assume that reef fish recruit from one reef to another.
Rather, it seems that many species have young that remain close to home. And this means conservation and management of reef fish will be reconsidered. If every reef has genetically distinct populations of fish, managers can't assume that new fish will arrive from outside sources. So individual reefs may need more protection than they've received so far. The good news is that in December, President Clinton established the Northwest Hawaiian Islands Reserve.