Rodrigo Gurdek - AIMS@JCU

Rodrigo Gurdek

rodrigo.gurdek@my.jcu.edu.au

PhD
College of Science and Engineering

Rodrigo Gurdek

rodrigo.gurdek@my.jcu.edu.au

PhD
College of Science and Engineering
Spatial and temporal connectivity dynamics of Lutjanus carponotatus in the Great Barrier Reef using biophysical modelling and genomics

Rodrigo's main fields of research are population connectivity of marine organisms, including genetic and hydrodynamic connectivity, as well as population ecology of coastal fish. He completed a BSc (Hons) in Biological Sciences (Oceanography) at the Faculty of Sciences of the University of the Republic of Uruguay. After this, he worked as a research assistant for a few years at the Oceanography and Marine Ecology Department of the same institution. During this time, he also studied the structure and functioning of estuarine fish assemblages, by undertaken a MSc in Geosciences. Rodrigo's research is expected to contribute to the conservation and sustainable management of marine organisms.

Spatial and temporal connectivity dynamics of Lutjanus carponotatus in the Great Barrier Reef using biophysical modelling and genomics

2016 to 2020

Project Description

The project will estimate the inter-annual variability (including different ENSO events) of dispersal, connectivity, local retention and self- recruitment levels of L. carponotatus larvae along the GBR, by biophysical modelling. Additionally, the population genomic structure of L. carponotatus will be evaluated along the central and southern GBR during different years, based on outlier and neutral SNP data from adults and recruits. Finally, the larval connectivity patterns will be compared to the genomic population structure results.

Project Importance

Larval transport is a critical stage for connectivity, recovery and persistence of marine populations. Larval connectivity of marine organisms can be affected by the dynamics of the marine environment. With relatively small home ranges and a relatively long pelagic larval phase, the model reef-associated fish, L. carponotatus is dependent on currents to link their GBR sub-populations. By using genomics and hydrodynamic modelling tools over time, a comprehensive understanding of the connectivity dynamics of larval fish along the GBR will be presented for the first time. A better understanding of these dynamics and interactions between environmental and biological systems will enable effective designation of MPA networks and management policies for marine organisms along the world's largest coral reef ecosystem.

Project Methods

Tissue samples from adults and recruits collected along the GBR were sent to Diversity Arrays Technology for SNP genotyping. The genetic connectivity will be quantified by evaluating the population genomic structure applying population genetic analyses to outlier and neutral SNP data. The hydrodynamic connectivity of L. carponotatus larvae will be estimated along the system by using the eReefs hydrodynamic ocean model and particle tracking techniques, from 2010 to present.

Project Results

Larval connectivity dynamics analysed at a 4km resolution scale along the GBR showed different responses to interannual and ENSO events. Larval retention levels estimated during La Niña events presented the lowest levels compared to estimated levels of retention during El Niño or neutral events. In general terms, self-recruitment levels were also lower during La Niña events. Larvae dispersed mostly towards the north of the releasing points during La Niña events, while dispersal towards southern areas was also detected during El Niño events. Dispersal of larvae between GBR regions (far northern, northern, central, southern GBR) was also observed.
High genetic connectivity of L. carponotatus was identified along central and southern GBR populations. However, population genetic analysis over time presented temporal differences when employing a set of potential outlier SNPs.

Keywords

Behaviour,
Benthic,
Biostatistics,
Climate change,
Coral reefs,
Distribution,
Ecology,
Field based,
Fish,
Genetics,
Interaction,
Management tools,
Marine planning,
Modelling,
Molecular techniques,
Oceanography,
Pelagic,
Quantitative marine science,
Remote Sensing,
Temporal change

Supervised By:

Lynne van Herwerden (JCU)