Congratulations to Ms Carolina Vargas-Caro for the successful completion of her PhD at the University of Queensland. Carolina was co-supervised by Mike Bennett of the Shark and Ray lab and Jenny Ovenden of the Molecular Fisheries Laboratory. Photo: Carolina and Peter Last at CSIRO Fish Collection in April 2014 measuring skate specimens.
A team of MFL researchers, led by PhD student Ms. Carolina Vargas-Caro, has published new information to assist with the sustainable exploitation of Chilean skates. As a fishery resource, skates are susceptible to overexploitation. They often occur in shallow inshore areas making them easily accessible to fishers. Their rate of reproduction is slow and the number of offspring produced is low. Exploitation rates need to be carefully considered to ensure populations can support seafood production now and in the future. This new work shows there are three genetically-distinct stocks on the Chilean coastline. Spatially-explicit models of population size and effects of harvesting need to match this stock structure to be most accurate.
Genetics – a powerful tool for improving management of skate populations. Genética – una poderosa herramienta para mejorar la administración pesquera de poblaciones de rayas
The MFL team are putting the final touches on the genetic analyses of the Chilean skate project. Skates are threatened worldwide. There are many examples of management plans that do not provide enough protection against overfishing. The two species in Chile are a good example. New genetic data show several management units for Zearaja chilensis and Dipturus trachyderma along the Chilean coastline. Neither species is likely to be adequately protected under the current fishery management arrangements to the north and south of 41.28oS. The genetic analyses suggest that females return to the same inshore nursery grounds to lay their eggs, which is supported by other features of their biology. Outside breeding season, adults of both species may move north and south, although genetic data suggests that the smaller of the two species (Z. chilensis) may move less than D. trachyderma. ______________________ El equipo MFL está poniendo los toques finales a los análisis genéticos del proyecto sobre rayas chilenas. Las rayas se encuentran amenazadas en todo el mundo. Hay muchos ejemplos de planes de manejo los que no proporcionan suficiente protección contra la sobrepesca. Las dos especies en Chile son un buen ejemplo. Nuevos análisis genéticos evidencian varias unidades de manejo para Zearaja chilensis y Dipturus trachyderma a lo largo de la costa chilena. Ninguna de las especies es probable que se encuentre adecuadamente protegidas bajo las disposiciones actuales de ordenación pesquera, asociadas al norte y al sur del paralelo 41.28oS. Los análisis genéticos sugieren que las hembras regresan a las mismas zonas costeras para poner sus huevos, lo que es apoyado por otras características de su biología. Fuera de la temporada de cría, los adultos de ambas especies pueden moverse a lo largo de la costa chilena, aunque los datos genéticos sugieren que la especie de menor tamaño (Z. chilensis) podría desplazarse menos que D. trachyderma.
The Molecular Fisheries Laboratory at the University of Queensland has just released eFish. eFish is a virtual library of genomic data for marine fish species. It is a major part of the project “Genome diversity of elasmobranchs of the Pacific Ocean Rim: Bioinformatics for conservation and management of populations” led by Dr Carlos Bustamante at the MFL. eFish is the genomic database repository of the Molecular Fisheries Laboratory and is hosted by The University of Queensland. eFish stores data produced by MFL projects and has been created to ensure fair access and use of this raw data. Re-use arrangements can be granted with a Creative Commons baseline licence, which grants permission free-of-charge to create non-commercial, no derivative works. Carlos Bustamante says “Our Lab is at the forefront of emerging technologies for whole‐genome descriptions, especially in marine fishes. Only 10 whole mitochondrial genomes of marine fishes have been produced in Australia, and the majority have been assembled within the Molecular Fisheries Laboratory”. According to Jenny Ovenden “Most studies of intraspecific genetic diversity have examined information from a single locus. Although the problem of inferring a species evolutionary history based on one gene has been addressed both empirically and theoretically, researchers still often make conclusions regarding evolutionary history based solely on mitochondrial sequence data, relying on the assumption that variation in mtDNA and nDNA are representative of variation in the whole genome. There are many reasons why this assumption might be violated, for example, demographic fluctuations, or hybridization can cause different loci to show dramatically different patterns of diversity”. eFish capitalises on UQ’s research strengths in marine science, marine fishes ecology, fisheries‐related molecular genetics, genome sequencing and bioinformatics infrastructure, and will extend Next‐Generation Sequencing technologies into the broader scientific community, providing an innovative and interdisciplinary platform to harvest key data from the genome diversity across marine fish species.
This week postgrads from MFL and the Bennett lab at UQ are presenting their work at the Oceania Chondrichthyian Society conference in New Zealand. Left to right: Safia Maher - tiger sharks, Deb Bowden - grey nurse sharks, Carolina Vagas-Caro - Chilean skates, Bonnie Holmes - tiger sharks, Kate Burgess - Manta rays Photo: Carlos Bustamante
Three MFL students have been awarded funds for travel and research. Carolina Vargas-Caro and Safia Maher received Student Travel Awards to attend the upcoming conference of the New Zealand Marine Sciences Society and Oceania Chondrichthyan Society at the University of Auckland 6 - 9th July 2015. Carolina will speak about her work on the population genetics of Long-nose Skates and Safia Maher will present a poster on Tiger shark genetics. Samuel Williams has received two awards from the Australian Society of Fish Biology. The Michael Hall Student Award will support Sam's research on the global population genetics of Black Marlin and the John Glover Award will support Sam's attendance at the ASFB conference in Sydney in 2015. An MFL photo shows Sam Williams (left), Carolina Vargas-Caro (top row, left) and Safia Maher (top, right) along with Mike Bennett, Carlos Bustamante, Einar Nielsen, Jenny Ovenden, Kate Burgess and Deb Bowden (left to right). Kate also received a travel award to the New Zealand conference to present her work on the ecology of the Giant Manta Ray (supervisor: Mike Bennett).
Laboratory analyses for the Chilean skate project are underway at MFL at the University of Queensland in Brisbane. This follows extensive field work and specimen collection at the end of 2014, led by Carolina Vargas-Caro and in collaboration with Chilean fisheries biologists. Carolina is testing a range of new microsatellite loci on the yellow-nosed skate (Zearaja chilensis). When the testing is finalised, these loci will be used to examine the fisheries stock structure of the species in Chilean waters. Nucleotide sequencing of regions of the mitochondrial genome is also underway. This data will be used to corroborate population structure as well as confirm species identity.
MFL is undertaking a large project to study the population genetics of skates in Chilean waters. The information will be used by the Chilean government to regulate the harvest of these species to ensure sustainability into the future. MFL members Carlos Vargas-Caro and Carlos Bustamante have been working in Chile with colleagues to obtain tissue samples and other biological information for the project. Left to right: Yhon Concha, Jorge Sandoval, Cynthia Diaz, Astrid Isla, Carolina Vargas-Caro, Mackarena Guenuman and Carlos Bustamante in Valdivia, Chile. 12th of November 2014.
Carolina Vargas-Caro and Carlos Bustamante are in Chile to take skate samples from the fishery. Here Carolina is meeting with staff of the Universidad Austral de Chile. Permits have been organised and the sampling is scheduled to begin next week. The two target species are Zearaja chilensis and Dipturus trachyderma as part of the Chilean skate project to define population units for improved management. Morphological data will be recorded for each specimen and tissue samples taken for downstream genetic analyses. Photo shows Carlos Bustamante with Jose Luis Brito (NH Museum of San Antio) and Julio Lamilla (Instituto de Ciencias Marinas y Limnológicas, Universidad Austral de Chile).
The mitogenome of Zearaja chilensis was published this week by Carolina Vargas-Caro and her collaborators at MFL. Carolina will travel to Chile in October 2014 to work with fisheries authorities there to determine the spatial extent of this and similar species. Download the paper here.