Investigators: Gavin Gouws (SAIAB, South Africa); Jérome Bourjea (IFREMER, Réunion); Delphine Muths (IFREMER, Réunion); Monica Mwale and Ofer Gon (SAIAB, South Africa); Blandina Lugendo (UDSM, Tanzania); James Mwaluma (KMFRI, Kenya)
MAP OF STUDY SITES
Click on the white-marked areas to see a close-up on the study sites
As taxonomic and distributional knowledge of the Western Indian Ocean marine fish fauna is advancing, an understanding of the origins of the WIO fauna, the relationships of its various regional components and the processes that have led to their establishment can be realized and is a necessary progression. However, such questions have only been addressed with limited taxonomic consideration and incidentally in accounts of the entire Indo-Pacific. The WIO possesses a diverse fauna and regional components show substantial endemism, yet there is no clarity of the origin of such faunas: whether these were established and maintained from dispersal from a hyper-diverse centre of origin (the Indo-Malaysian region), or result in situ from a series of vicariant events resulting from the physical, geological and oceanographic changes that sculpted the present features of the WIO. Understanding the relationships among the faunas of the various regions and, particularly, the processes and factors that have determined this are critical for both understanding and conserving the marine biodiversity of the WIO. With the importance of marine resources to WIO rim countries and these resources under increasing pressure, conservation measures need to be effective. Efficacy of interventions such as the designation of Marine Proteced Areas is directly contingent on an understanding of patterns of differentiation, the identification of unique biogeographic regions and an understanding of historical and contemporary processes, such that measures can be implemented at the appropriate spatial scale.
In this proposal, we propose research that will implement a molecular genetic approach to consider differentiation and connectivity of selected reef fish species within the WIO at two distinct spatial and temporal scales. Using sequence data and a phylogenetic and biogeographic framework, one project component will identify biogeographic and phylogeographic provinces, consider patterns of differentiation and relationships among regional faunas, examine historical patterns of establishment and attempt to identify the historical and contemporary processes responsible for current relationships and distributions. Incidentally to this, the specific status of widespread species (often problematic when considering traditional morphological taxonomy) will be considered. The second component will consider fine-scale contemporary patterns of genetic diversity, spatial genetic differentiation and genetic connectivity at a finer regional scale among three fish species of commercial importance to local communities. This will elucidate contemporary patterns of connectivity and migration.
This aspect will determine the efficacy of current reserve or Marine Protected Area networks, whether these systems are isolated or whether they receive sufficient extraneous inputs to sustain populations. A critical consideration will be the extent to which genetic data can aid in the designation of reserves, be incorporated in reserve selection models, or support management decisions.