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Above: A white with orange and dark splotches morph.

Below: An impossible sight-except at St. Paul’s Rocks, were these two color variants of H. ciliaris are encountered.

islands in the South Atlantic (Lubbock 1980; Gasparini & Floeter 2001). St. Paul’s Rocks are the farthest location inhabited by H. ciliaris in the South Atlantic, and it probably reaches the Rocks utilizing Atol das Rocas and/or Fernando de Noronha Archipelago as stepping-stones

for colonization. The icthyofauna of these islands are, in fact, considered very similar in a recent biogeographic analysis (Floeter & Gasparini 2000). Despite its relative proximity, the very low density of H. ciliaris in the Fernando de Noronha Archipelago (SR Floeter pers.

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obs.) should contribute to the isolation of St. Paul’s population by providing a very little output of recruits (and consequently low genetic flow). The St. Paul’s population of H.ciliaris are thus probably maintaining themselves mainly by self-recruitment (Swearer et al. 1999; Jones et al. 1999; Robertson 2001).

A PLEA FOR CONSERVATION

It is clear that marine species are not exempt from human impacts and extinction risk (Roberts & Hawkins 1999; Hawkins et al. 2000). Our observations show that this population of H. ciliaris posses some risk characteristics:

(1) Restrict geographic range. As defined by Robertson (2001), genetically distinct isolated populations, as in this case, should be treated as endemic species. The only putative case of extinction registered for a reef fish was an island-endemic species (Roberts & Hawkins 1999).

(2) Importance in the aquarium trade. The isolation of St. Paul’s Rocks is not an obstacle

January 2003

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