Project Number: 8030-31000-005-16-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Jul 1, 2020
End Date: Jun 30, 2021
The first objective is to evaluate the field performance of genetically selected Eastern oysters in varying geographic regions and develop localized selective breeding strategies that improve performance for economically important traits including growth and disease resistance. The cooperator will help in obtaining selectively bred lines of oysters and in evaluating their growth and survival. The second objective is to determine the susceptibility of North American Atlantic salmon selected for improved performance to new and emerging pathogens and develop strategies to improve fish health. The Agricultural Research Service (ARS) will work with the cooperator to monitor infectious salmon anemia virus non-deleted highly polymorphic region (ISAV HPR0) in selected Atlantic salmon. Assays will be optimized to detect ISAV HPR0 in water and fish tissues. The third objective is to develop a cheaper and quicker method to detect off flavor in Atlantic salmon grown in recirculating aquaculture systems (RAS). ARS and the cooperator will look at methodologies to optimize off flavor detection in Atlantic salmon.
Two extant lines, UMaine Flowers Select and Maine commercial industry northern line, and a third “wild” northern line will be used to establish a rotational breeding program. In each generation, three distinct lines will be maintained but genetic diversity maximized through interline crosses. We will monitor comparative field performance of progeny against the industry standard Rutgers Northeast high survival line (Haskin NEH®) paying particular attention to cold-water growth, overwinter mortality and tolerance/resistance to Haplosporidium nelson and Roseovarious oyster disease. Because improved production rests on more than just selective breeding, we will characterize growth with respect to detailed oceanographic data. By careful characterization of growth (including shell and viscera), feeding physiology, cycling of internal energy stores (carbohydrates, lipids and proteins), and grow-out conditions, we can scale up results for one of the longest tidal shorelines in the nation. Specifically, grow-out conditions will be monitored by a nearshore observing system designed by growers and maintained by the University of Maine team (maine.loboviz.com). ISAV is a highly contagious and economically significant pathogen in farmed Atlantic salmon. Pathogenic variants of ISAV are referred to as ISAV highly polymorphic region (HPR)- deleted and contain a deletion in the HPR of the gene that encodes the haemagglutinin-esterease (HE) protein. A non-pathogenic form of ISAV, a full-length gene ISAV non-delete (HPR0), has been detected in both farmed and natural Atlantic salmon populations globally. Our research will optimize assay(s) for HPR0 detection and quantification in environmental samples, salmon tissue and gametes. Methods will involve developing new cell culture and molecular assays such as quantitative reverse transcriptase polymerase chain reaction (RT-qPCR) techniques guided by regulatory approved assays. Recirculating aquaculture systems (RAS) for salmon production is growing rapidly in the United States. RAS are state-of-the-art tank-based culture systems with advanced filtration systems and represent one of the most ecologically sustainable animal production systems in the world. Off flavors and odors caused by geosmin (GSM) and 2-metholisoborneol (MIB) from the recirculating water can accumulate in salmon flesh decreasing the fish meat quality. Many pre-concentration methods have been used in the past, such as liquid-liquid extraction (LLE), steam distillation extraction (SDE), head space-sorptive extraction (HSSE), and solid phase microextraction (SPME). These methods, while effective, were often laborious, time consuming, and generally lacking in the necessary sensitivity required for aquaculture. Stir Bar Sorptive Extraction (SBSE) is a recently developed concentration method that uses polydimethylsiloxane (PDMS)/ethylene glycol (EG) stirring rods or “twisters” capable of absorbing and concentrating organic solutes directly from aqueous solutions. ARS and collaborator will validate this new method to be used for water and tissue samples.