Oral Presentation Australian Society of Fish Biology and Oceania Chondrichthyan Society Conference 2016

Integrative approach to elucidating the population structure of coastal reef fish in northern Australia (Part III: Genetics and summary) (#61)

Laura Taillebois 1 , Di P Barton 1 2 , Jonathan Taylor 2 , David A Crook 1 , Thor Saunders 2 , Alan Grieg 2 , Mark Hearnden 2 , David J Welch 3 , Stephen J Newman 4 , Michael J Travers 4 , Richard J Saunders 5 6 , Christine Dudgeon 7 , Safia Maher 7 , Jennifer Ovenden 7
  1. Research Institute for the Environment and Livelihoods, Charles Darwin University, Darwin, Northern Territory, Australia
  2. Department of Primary Industry and Fisheries, Northern Territory Government, Berrimah, Northern Territory, Australia
  3. C2O Fisheries, Cairns, Queensland, Australia
  4. Western Australian Fisheries and Marine Research Laboratories, Government of Western Australia, North Beach, Western Australia, Australia
  5. Centre for Sustainable Tropical Fisheries and Aquaculture, James Cook University, Douglas, Queensland, Australia
  6. Animal Science, Queensland Department of Agriculture and Fisheries, Brisbane, Queensland, Australia
  7. Molecular Fisheries Laboratory, School of Biomedical Sciences, The University of Queensland, St Lucia, Queensland, Australia

Modeling fisheries populations is one of the many components of management aimed at achieving sustainable exploitation. Definition of the spatial extent of stocks, in particular, is a founding principle of this assessment process. The concept of stocks as natural management units is based on demographically cohesive groups of individuals of a species and is commonly defined in genetic terms. The status of coastal reef fisheries in northern Australia remains undefined for many exploited species. In this study, we aimed to identify the stock structure of three commercial and recreationally important fish species across northern Australia (Protonibea diacanthus, Lutjanus johnii and Lethrinus laticaudis) using a combination of ecological, geochemical and genetic techniques for uptake into fisheries management. All three species were sampled across their Australian distributional range and between 10-13 genetic microsatellite DNA markers were specifically developed for each species. The distribution of the genetic diversity was characterized and tested using F-statistics and Bayesian model-based approaches, and revealed contrasting results between the three species. Protonibea diacanthus and Le. laticaudis presented low but significant FST and the Bayesian clustering revealed distinct populations and major genetic breaks, whereas no pattern of genetic structure was revealed for Lutjanus johnii. Our holistic approach to stock discrimination combines and integrates parasites abundances, otolith microchemistry and population genetics. The different levels at which these three techniques operate - from the individual life history to multi-generational levels of population connectivity - ensures that if stock structure exists, it has more chance to be revealed and elucidated than using a single technique.