Spatial ecology, genetic barcoding, and vulnerability of tropical Indo-West Pacific batoids, with a focus on Australian species

  • Florencia Cerutti

    Student thesis: Doctor of Philosophy (PhD) - CDU


    Tropical batoids are abundant and important members of coral reef fish communities. Their populations are subject to intense pressure from fishing and habitat degradation, but due to their distinct life-history traits, can only withstand modest levels of decline without stock collapse. Despite this, basic knowledge to ensure their effective conservation and management is lacking. This project addressed this need by combining several current and innovative research tools to assist the integrated management of batoids in northern Australia (NA) and the Indo-West Pacific (IWP).

    DNA-barcoding was used to confirm the identification of 16 batoid species at Ningaloo Reef (NRMP), Western Australia. It demonstrated its potential to confirm field identifications where taxonomic uncertainty might confound ecological data, although two major sets of problems limiting its application were also identified.

    Passive acoustic monitoring was used to study the spatial ecology of batoids in the lagoon of NRMP. By using acoustic receivers, the first confirmed nursery area for tropical juvenile batoids in the IWP was identified - a shallow embayment that recorded most of the detections. Adult rays showed sexual segregation of core areas of activity inside the lagoon, with juvenile and adult rays, moving beyond protected areas. Little evidence of habitat partitioning among species was found at large spatial scales, despite differential use of microhabitats. The current zoning of the NRMP provides effective protection for core areas ofactivity but not for larger movement ranges. As such, spatial management will require large areas of protection to ensure the conservation of these species.

    An ecological risk assessment (ERA) was employed to assess the vulnerability of tropical batoids to the risk of fishing and habitat degradation in NA and IWP. The ERA methodology was also used to identify and rank research gaps and priorities. Finally, the applicability of these tools, and findings, to the conservation and integrated management of tropical batoids in NA and the IWP, and future research directions, are discussed.
    Date of AwardJul 2012
    Original languageEnglish
    SupervisorKaren Edyvane (Supervisor) & Peter M. Kyne (Supervisor)

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