High genetic connectivity across the Indian and Pacific Oceans in the reef fish Myripristis berndti (Holocentridae)

Abstract

To assess patterns of connectivity among populations of an Indo-Pacific reef fish, we surveyed mtDNA of the bigscale soldierfish Myripristis berndti (Holocentridae), which is concentrated on reefs at intermediate depths, but occurs to at least 160 m. Our multi-scale approach included sampling at 11 sites spanning the entire range of the species from the western Indian Ocean to the eastern Pacific, across 240°of longitude (total N = 278), and 9 islands throughout one of the largest and most isolated archipelagos, the Hawaiian Islands (subtotal N = 147). Analysis of cytochrome b sequences demonstrated the following: (1) common haplotypes are shared among all sample localities, (2) there is modest population structure across the entire species range (Φ st = 0.211; p < 0.001), (3) there is no structure among the Hawaiian Islands (Φ st = 0.0004; p = 0.4107), and (4) there is no structure across the central-west Pacific (Φ st = -0.007, p = 0.634). Population separations across the East Pacific Barrier were significant (overall Φ st = 0.278, p < 0.001; pairwise range Φ st = 0.107 to 0.424), yet significantly weaker than those across the Indo-Pacific Barrier (overall Φ st = 0.583, p < 0.001; pairwise range Φ st = 0.329 to 0.810; Mann-Whitney U-test, p < 0.001). When grouped by major biogeographic province, populations showed no difference within the central-west Pacific (Φ st = -0.007, p = 0.634), within the Indian Ocean (Φ st = -0.027, p = 0.528), or within the east Pacific (Φ st = -0.061, p = 0.920). Mismatch distributions and coalescence analysis indicated a rapid population expansion on the order of ~500 000 yr before present (range 300 000 to 10 6 yr depending on mutation rate). Despite having a vast distribution and broad depth range, M. berndti shows the genetic signatures of a population bottleneck and recovery similar to shallow reef specialists that were displaced or extirpated during glacial maxima. Overall, the mtDNA data indicated a dispersal capability in M. berndti which far exceeds that of typical reef fishes. While recent genetic studies demonstrate limited larval dispersal in some reef fishes, it is clear that others, including soldierfishes, are extensive dispersers.

Molecular Characteristics of Batanghari, Tambago, Orange, and Mandiangin Giant Gourami Strains

“…This condition might be due to no genetic exchange between those two islands because seeds transportation mainly tends to occur on the island. This result was also similar to another part of Craig et al (2007) and Craig et al (2009) studies in two reef fish species where significant genetic differences were found among large geographically separated populations. Moreover, strong genetic structures were also observed among geographically separated cyprinids populations (Durand et al, 2002) and among Orizyas latipes populations Takehana et al (2003).…”

“…In case of Sumatera strains, our study has a similar result to a part of Craig et al (2007) study in reef fish Myripristis berndti where no genetic differences were observed in rather narrow areas such as within Central Pacific (Φ st = -0.007, p = 0.634), within Indian Ocean (Φ st = -0.027, p = 0.528), and within the east Pacific (Φ st = -0.061, p = 0.920). The present study and previous study from Craig et al (2007) indicates low rates of molecular evolution in mitochondrial cytochrome b gene which lead to no genetic structuring among populations in small geographic scales. Therefore, it is not surprising if a low level of genetic differences were observed in cyt b gene among morphologically different giant gourami strains in Sumatera.…”

“…This value indicates that the used marker has a low level of polymorphisms. Low genetic polymorphisms were also observed in Myripristis berndti (Craig et al, 2007) and in Ephinepenlus itijara (Craig et al, 2009). This similar result indicates that low level of genetic polymorphisms can be observed in the broad scope of fish species.…”

“…Complete data on haplotype and nucleotide diversity are presented in Table 1. Craig et al (2007) in twenty populations of coral reef fish Myripristis berndti (h= 0.286-0.829) from geographic widely separated populations, and Craig et al (2009) in goliath grouper Ephinepenlus itijara from Panama, Bezile, Brazil, and Florida populations (h=0.324-0.684). According to our result in giant gourami and those previous studies, it is likely that moderate haplotype diversity is rather common in cyt b gene of fish taxa.…”

Surgeons and suture zones: Hybridization among four surgeonfish species in the Indo-Pacific with variable evolutionary outcomes

“…Nonetheless, fishes with a long pelagic larval stage tend to have extensive dispersal, broad ranges and dominate communities on isolated islands (Horne et al, 2008;Reece et al, 2011;. Some of the most dispersive reef fishes are those that can stay in the water column after transforming from larva to juvenile (or pre-juvenile), including trumpetfishes (Bowen et al, 2001), squirrelfishes (Craig et al, 2007) and (most relevant) other surgeonfishes (Thresher, 1984). The sister species surveyed here provide additional examples of highly dispersive fishes, a trait that may be a general feature of the genus Acanthurus (Eble et al, 2011).…”