The influence of reproductive strategies and larval behaviours on the population genetic structure of the sponge Rhopaloeides odorabile

Steve Whalan, PhD student, James Cook University

Sponges are widely used for cosmetic and biomedical applications. Often, commercial success requires the target species to be sourced from either wild harvesting or aquaculture, potentially placing pressure on targeted sponge populations.

For example, over-harvesting and translocations for culturing purposes have the potential to lead to loss of unique genetic variation, or even localised extinction.

Because harvesting and culture of sponges can contribute to environmental impacts, sustainable management of exploited sponge populations will partly rely on fundamental ecological and biological information. Knowledge of the key ecological processes that contribute to population maintenance will enable us to understand the scale of recruitment, genetic connectivity between populations, and ultimately boundaries of management units.

The sponge Rhopaloeides odorabile occurs throughout the Great Barrier Reef and has commercial potential as a bath sponge. This study will elucidate the spatial scale over which genetic connectivity is effective for R.odorabile populations, using allozyme, mitochondrial and microsatellite markers. In addition to this, histology and manipulative experiments will be undertaken to assess the influence of reproductive strategies and larval dispersal on the genetic structure of R.odorabile populations. This information will be important for the conservation and management of this species should it be exploited.