Meeting Abstract
S4.11 Wednesday, Jan. 5 How Nemo finds home: neuroecology of larva dispersal and population connectivity in marine, demersal fishes LEIS, J.M.*; SIEBECK, U.; DIXSON, D.L.; Australian Museum, Sydney; University of Queensland, St Lucia; James Cook University, Townsville jeff.leis@austmus.gov.au
Teleost reef fishes have a bipartite life history: a demersal adult phase with limited mobility and a dispersive, pelagic larval phase that lives in open water for several weeks to months before settling onto a reef. Larval dispersal is a biophysical process, so, behaviour of fish larvae influences dispersal outcomes, thus setting the scale of population connectivity. Orientation by small pelagic animals in a moving water column is challenging, and the sensory cues and systems used by larvae for orientation are poorly understood. The little existing research has focused on sound, smell and sight, but has revolutionized our view of the capabilities of these small fishes (5-30 mm). Larval fishes can hear reefs from several km and localize underwater sound sources, yet the physiological mechanisms used are unclear. Larvae can distinguish different reefs by scent, locate settlement habitat by scent, and avoid predator scents, but the scale over which can be done is unclear. Direct use of vision for orientation is limited by water clarity to a few 10s of m, but larval-fish visual orientation over very large scales using celestial cues or polarized light is implied by a few studies. Use of other cues by larval reef fishes, such as wave direction or magnetic fields has been hypothesized, but not studied. Several orientation cues operating over different spatial scales are likely used. An integrated approach combining laboratory work on electro-physiology & functional morphology and field work on sensory ecology are required to understand larval-fish orientation. Such understanding is essential to model and measure dispersal and population connectivity, and to manage living marine resources and marine protected areas.
