Title
How many species of goliath grouper are there? Cryptic genetic divergence in a threatened marine fish and the resurrection of a geopolitical species
Author(s)
Craig M.T., Graham R.T., Torres R.A., Hyde J.R., Freitas M.O., Ferreira B.P., Hostim-Silva M., Gerhardinger L.C., Bertoncini A.A., Robertson D.R.
Published
2009
Publisher
Endangered Species Research
Abstract
The goliath grouper Epinephelus itajara (Epinephelidae) is an exceptionally large marine fish that inhabits sub-tropical and tropical waters of the Americas and western Africa. Due to a lack of readily observable morphological variation in specimens across its range, the goliath grouper has been regarded as a single species. We tested the hypothesis that Pacific and West Atlantic populations constitute a single species by analyzing nuclear and mitochondrial DNA sequence data. We found numerous fixed genetic differences for mitochondrial loci between Pacific and West Atlantic goliath grouper (genetic distance D ˜ 3.5% at 16S and D ˜ 6% at cytochrome b; st = 0.98 [p < 0.001] for 16S and st = 0.98 [p < 0.001] for cytochrome b). The nuclear S7 intron showed 3 fixed nucleotide differences between Pacific and West Atlantic populations. Within the West Atlantic, we found few absolute genetic differences (D < 0.01 at 16S and D < 0.02 at cytochrome b), but statistically significant population structure based on haplotype frequency data (st = 0.04 [p = 0.05] at 16S; st = 0.14 [p < 0.001] at cytochrome b). These data indicate that (1) goliath grouper in the West Atlantic are subdivided into discrete populations, (2) goliath grouper populations in the Pacific and western Atlantic represent 2 (or more) distinct species, and (3) these distinct populations/species require separate management and conservation strategies. We resurrect the species Epinephelus quinquefasciatus (Bocourt 1868) for Pacific goliath grouper. © Inter-Research 2009.
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PUB11872