title: Limited contemporary gene flow and high self-replenishment drives peripheral isolation in an endemic coral reef fish.
abstract: Extensive ongoing degradation of coral reef habitats worldwide has lead to declines in abundance of coral reef fishes and local extinction of some species. Those most vulnerable are ecological specialists and endemic species. Determining connectivity between locations is vital to understanding recovery and long-term persistence of these species following local extinction. This study explored population connectivity in the ecologically-specialized endemic three-striped butterflyfish (Chaetodon tricinctus) using mt and msatDNA (nuclear microsatellites) to distinguish evolutionary versus contemporary gene flow, estimate self-replenishment and measure genetic diversity among locations at the remote Australian offshore coral reefs of Middleton Reef (MR), Elizabeth Reef (ER), Lord Howe Island (LHI), and Norfolk Island (NI). Mt and msatDNA suggested genetic differentiation of the most peripheral location (NI) from the remaining three locations (MR, ER, LHI). Despite high levels of mtDNA gene flow, there is limited msatDNA gene flow with evidence of high levels of self-replenishment (≥76%) at all four locations. Taken together, this suggests prolonged population recovery times following population declines. The peripheral population (NI) is most vulnerable to local extinction due to its relative isolation, extreme levels of self-replenishment (95%), and low contemporary abundance.
authors.affiliation: Molecular Ecology and Evolution Laboratory, Australian Tropical Sciences and Innovation Precinct, James Cook University Townsville, 4811, Australia ; School of Marine and Tropical Biology, James Cook University Townsville, 4811, Australia ; ARC Centre of Excellence for Coral Reef Studies, James Cook University Townsville, 4811, Australia.
authors.forename: Martin H
authors.initials: MH
authors.lastname: van der Meer
authors.forename: John B
authors.initials: JB
authors.lastname: Horne
authors.forename: Michael G
authors.initials: MG
authors.lastname: Gardner
authors.forename: Jean-Paul A
authors.initials: JP
authors.lastname: Hobbs
authors.forename: Morgan
authors.initials: M
authors.lastname: Pratchett
authors.forename: Lynne
authors.initials: L
authors.lastname: van Herwerden
keywords: Chaetodon; Lord Howe Island; Norfolk Island; coral reefs; extinction risk; marine dispersal