title: A magnetic compass that might help coral reef fish larvae return to their natal reef.
abstract: Many coral reef fish larvae spend days to months in the open ocean before settlement on coral reefs [1]. Early in development, larvae have limited swimming capabilities and will therefore be greatly affected by currents. This can potentially result in dispersal distances of tens of kilometers [2]. Nevertheless, up to 60 % of surviving larvae have been shown to return to their natal reefs [2]. To home, the larvae must develop strong swimming capabilities and appropriate orientation mechanisms. Most late-stage larval reef fish can, after being passively drifted for days to weeks, swim strongly [3], and Ostorhinchus doederleini larvae have been shown to use chemotaxis to identify their natal reef once in its vicinity [2] and a sun compass for longer distance orientation [4] during the day. But how do they orient at night? Here, we show that newly settled fish caught at One Tree Island (OTI) at the Capricorn Bunker Reef Group (Great Barrier Reef) can use geomagnetic compass information to keep a south-east heading. This behavior might help them return to their natal reef in the absence of any celestial cues at night.
authors.affiliation: Institute of Biology and Environmental Sciences, University of Oldenburg, Germany. Electronic address: michael.bottesch@uni-oldenburg.de.
authors.forename: Michael
authors.initials: M
authors.lastname: Bottesch
authors.affiliation: Institute of Biology and Environmental Sciences, University of Oldenburg, Germany; Research Center for Neurosensory Sciences, Carl-von-Ossietzky Universität Oldenburg, Germany; School of Marine and Tropical Biology and ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Australia.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Gerlach
authors.affiliation: Institute of Biology and Environmental Sciences, University of Oldenburg, Germany.
authors.forename: Maurits
authors.initials: M
authors.lastname: Halbach
authors.affiliation: Institute of Biology and Environmental Sciences, University of Oldenburg, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Bally
authors.affiliation: School of Marine and Tropical Biology and ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Australia.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Kingsford
authors.affiliation: Institute of Biology and Environmental Sciences, University of Oldenburg, Germany; Research Center for Neurosensory Sciences, Carl-von-Ossietzky Universität Oldenburg, Germany.
authors.forename: Henrik
authors.initials: H
authors.lastname: Mouritsen
mesh_terms: D000818:Animals; D057894:Coral Reefs; D005399:Fishes / Q000502:physiology*; D007814:Larva / Q000502:physiology; D060526:Magnetic Fields; D009949:Orientation; D000071442:Taxis Response / Q000502:physiology*