Short-distance dispersal of black coral larvae:inference from spatial analysis of colony genotypes

Abstract

Ant~pathes fiordensis is a black coral species endermc to the south western reglon of New Zealand Restncted larval dlspersal has been demonstrated to occur In A fiordens~s although the exact scale of larval dlspersal is unknown Thls study examlnes the fine-scale (<50 m) pattern of relatedness between black coral colonles at 3 sltes in Doubtful Sound Fiordland to mfer dspersal &stance and gain a better understanding of patch size in this species At each of the 3 sites the position of all black coral colonles was mapped and allozyme electrophoresis was used to determine the 10-locus genotype of each colony Two statlstlcal methods were used to examine the association between colony genotype and dlstance at each of the 3 plots, spatlal autocorrelatlon of ~n&vidual loci and Mantels Test which exanunes the relatlonshlp between multi locus genotypes At 1 of the 3 sites (Trlcky Cove) there was a signif~cant positive association among colonles separated by < 5 m for 4 of the 6 loci tested Sinularly Mdntel s Test showed a signdlcant positive correlation between genetic distance and Euclidean distance at the Tricky Cove site (r = 0 2 p = 0 007) These results suggest dlspersal of black coral larvae 1s highly philopatnc and that larvae settle very close to parent colonles However at the other 2 sites there was no spatial associabon detected among genotypes indicating either that gametes or larvae are more widely dspersed at these 2 sites (>50 m) or that other ecological and evolutionary factors are operating that have influenced the observed genetic structure of the populations Genetic stu&es suggest that gene flow in A f~ordensis populations ~1 1 1 b e restncted and that patch size In this species may b e relatively small These findlngs w l l have Important mlplications for the conservation and management of the rare and unique shallow water populations of black corals In New Zealand s flords

Conflicting estimates of connectivity among deep‐sea coral populations

“…1997; Burgess & Babcock 2005), suggesting no obvious link between reproductive mode, larval dispersal and genetic structure. Observations of antipatharian larvae suggest that they may be negatively buoyant and only weak swimmers (Miller 1996) and, thus, unlikely to disperse far (Miller 1997, 1998). This is consistent with the genetic differentiation we have found between black corals on the Lord Howe Rise, Norfolk Ridge and Kermadec Ridge seamounts.…”

Phylogeography of New Zealand's coastal benthos

“…Nine studies have examined phylogeography within Fiordland, detecting genetic differentiation at very small spatial scales (<50 m) for some species (e.g., the coral Antipathes fiordensis ;Miller 1998), whereas other species such as the snake star (Astrobrachion constrictum; Steele 1999) with similar dispersal potential (i.e., PlD) showed little evidence of restricted larval exchange. Although all but one of these studies detected population subdivision either within or among the fjords, interpretation of phylogeographic patterns is complicated.…”

The evolutionary history of the order Antipatharia (Cnidaria: Anthozoa: Hexacorallia) as inferred from mitochondrial and nuclear DNA: implications for black coral taxonomy and systematics

“…There is currently no evidence of internal fertilization in antipatharians (Wagner et al ., ). Sexually produced larvae are lecithotrophic, negatively buoyant, negatively phototaxic, and generally poor swimmers that crawl along the substrate with a survival time of approximately 10 days (Grigg, [ Antipathes grandis Verrill, ]; Miller, [ A. fiordensis ]). Restricted larval dispersal (10–15 km) has been demonstrated in A. fiordensis from the fjords of south‐west New Zealand; while the exact scale is unknown (some estimates are > 50 m), dispersal is, in general, highly philopatric (5–10 m; Miller, ).…”