Spatial patterns, landscape genetics and post virus recovery of blacklip abalone, Haliotis rubra (Leach), in the Western commercial fishing zone of Victoria
Deakin University Geelong Waterfront Campus
Populations dynamics, habitat availability and physical environmental features influencing stock structure need to be considered in order to devise spatially effective management strategies. The need for demographic information at the genetic level is accentuated by the advent of Abalone Viral Ganglioneuritis (AVG) and associated stock depletions in the region in recent years. The genetic component of this project will determine the current genetic condition of abalone stocks and provide a framework for post-AVG stock recovery planning. For the first time, detailed seafloor structure information to depths of ~25 metres for the entire western abalone zone of Victoria is available. Whilst this information has primarily been collected by DSE Future Coasts Program for the assessment of coastal vulnerability, there is an opportunity to apply the data to determine the spatial extent of individual reef systems, connectivity between reef patches, and the relationships between seafloor structure information and genetic connectivity of abalone populations. The availability of these data also provides a unique opportunity to collate spatially-explicit fishery dependent data available for the western zone into a geographical information system (GIS) and integrate with LiDAR-derived seafloor information using a range of spatial analysis techniques. These data will facilitate investigations of abalone habitat suitability, identification of productivity hotspots (providing indications of productivity in relation to reef extent), and reef characteristics and environmental variables most influencing abalone habitat suitability. Further, the integration of geospatial and genetic data will provide longer term benefits by feeding into the WADA reef-scale assessment and management system Strategic research theme: Ecologically Sustainable Development; Victorian Abalone Fishery Management Plan (2002)- Need for better understanding of temporal and spatial aspects which will allow for management on a more refined spatial scale than is currently the case; ACA Strategic Research Plan (2007–2017) Platform 3: Harvest Optimisation, Objective 2f, 3h.
1. Investigate methodologies to integrate commercial catch data with LiDAR-derived seafloor structure information to identify spatial connectivity of reef systems and abalone habitat suitability.
2. Conduct a population genetic assessment of H. rubra in the Western Zone to determine stock population structure and assess the impact of AVG on genetic diversity and recruitment.
3. Integrate population genetics, landscape ecology and spatial analyses to elucidate how genetic variation in H. rubra is affected by landscape and environmental variables at the broad (Western Zone) and fine (Port Fairy to Warrnambool) spatial scales.
Principal Investigator: Daniel Ierodiaconou
Key Words: Haliotis rubra, microsatellite, LiDAR, GIS, genetic stock structure, fishery footprint modelling, hotspot analysis, recruitment patterns
Summary: This research has made several important findings that will improve the current management of the Victorian Western Zone blacklip abalone fishery, including post- Abalone Viral Ganglioneuritis (AVG) recovery planning. Geospatial and genetic technologies were used effectively to provide new information about potential habitat availability and fisheries productivity as well as key genetic parameters that reflect patterns of stock connectivity, genetic diversity and recruitment. Specifically, the outcomes of this project are:
1. The first high-resolution assessment of the extent of suitable fishing grounds derived from integrating commercial catch data with light detection and ranging (LiDAR) in spatially explicit models of habitat suitability and fishery footprint.
2. Patterns of change in spatial allocation of fishing effort identified from GPS tracked abalone diver data.
3. Impacts of AVG on genetic diversity and population structure across the Western Zone fishery.
4. Spatial patterns of larval recruitment determined from genetic measures of relatedness within and across reef complexes at various distance classes.