Aug 21, 2017

USDA Approves CTSA FY16 Plan of Work, New Projects Begin

The USDA recently approved the FY2016 Plan of Work, which includes funding for four new projects, one continuation project, and multi-year activities of three projects approved in previous Plans of Work.

The overall goals of the new project “Francisella noatunesis subsp. orientalis incidence and genetic assessment of feral Tilapia populations in Hawaii” are to determine the prevalence of Fno on islands other than Oahu, and to determine what species are infected and established in natural bodies of water in Hawaii. Francisellosis causes mortalities in temperate to tropical fish worldwide. In Hawaii, francisellosis has been linked to the large numbers of unexplained mortalities in cultured and feral populations of tilapia on Oahu. Molecular methods have identified the causative bacterium as Francisella noatunensis sp. orientalis (Fno). In an attempt to prevent the spread of the bacterium, the State of Hawaii Plant Quarantine Division issued a moratorium on exporting Oahu tilapia to the other Hawaiian Islands. However, it is unknown if Fno is present and/or the extent of its presence on the other Hawaiian Islands. To determine presence of Fno, tilapia will be euthanized with clove oil (Eugenol), necropsied, and examined with light microscopy. Samples of spleen will be collected for microbiological and histological detection of Fno. Additionally, spleen tissues will be submitted to Dr. David Weese at Georgia College and State University for Polymerase Chain Reaction (PCR) screening. To identify the species that harbor the Fno DNA, fin clips will also be taken for PCR analysis. Deliverables of this research are two-fold. One deliverable will be to determine of the incidence of Fno in feral tilapia populations. A second focus is to detect the presence of tilapia species and their hybrids in multiple drainages on Oahu, Maui, Kauai, Molokai and Hawaii. 

The new project “Disease Prevalence Survey of Wild Mud Crab Populations in the US-Affiliated Pacific Islands” will aim to determine the prevalence of harmful pathogens in wild populations of mud crabs in the USAPI, as well as in mud crabs imported into the region. Furthermore, the population genetic structure of local mud crab populations will be assessed to help determine species and origin of specimens. Mud crabs, also known as “mangrove crabs”, are widely sought after in South America, Southeast Asia, Australia and the Pacific Islands for human consumption. Inability of local habitats or farms to meet increasing demand has forced some restaurant owners and other individuals in US-Affiliated Pacific Islands (USAPI) to import crabs from surrounding areas such as Southeast Asia and the Philippines. This poses an immediate risk for the introduction and spread of crustacean pathogens. Mud crabs not only carry pathogens affecting their own survival and reproduction, but they also carry pathogens that can infect other commercially valuable crustaceans, such as the Pacific white shrimp Litopenaneus vannamei. Accordingly, researchers at Palau Community College (PCC) are concerned about the movement of pathogens between mud crab populations. Researchers at Oceanic Institute of Hawaii Pacific University (OI-HPU) have a history of working with disease pathogen testing and population genetics, and thus these two institutions will collaborate to determine the prevalence of harmful pathogens and the genetic structure of regional crab populations. They will first collect samples from wild and imported mud crab populations in Palau, Guam, Saipan, Pohnpei and Kosrae. They will then use established protocols to test for white spot syndrome virus (WSSV), Taura syndrome virus (TSV) and mud crab reovirus (MCRV). Their final objective is to develop microsatellite markers for use in mud crab and characterize the genetic structure in populations across the Pacific islands.

Also in Palau, the project “Testing the feasibility of Open Ocean Cage Culture of Grouper in Palau” will test the feasibility of grouper cage culture in Palau, with particular focus on density, growth rate, and FCR. Many tropical island communities have found that commercial fishing and export of seafood products are unsustainable in the long run, and can lead to decline of wild fish and invertebrate assemblages, imbalance of coral reef communities, and steadily declining incomes for fishermen and their families. Palau recently passed a law that forbids commercial fishing and export of reef fish species. They have established marine protected areas, strict controls of domestic fishing, and are looking to aquaculture to provide the products for export of their valuable reef species. However, additional research is needed to determine the feasibility of commercial cage culture of popular species, such as grouper, in Palau. Therefore, this project will obtain grouper fingerlings from the CTSA coral grouper hatchery project at the Palau Community College, or the National hatchery (Palau Mariculture Demonstration Center) to stock and monitor in deep water cages in Palau. The project will stock one cage with 4,000 grouper and a second cage with 1,000 grouper (12 KG and 3 KG /m3 at final harvest respectively) to see what effect stocking density has upon fish growth and time to market.  This density falls in the range of some other cultured species such as cobia and mutton snapper that have been tested in the past. The project will also conduct a market test live shipment to Hong Kong to determine the costs and feasibility of selling the grouper to that high price market.

The overall goals of the project “Cost-Effective, Local Aquatic Feeds for Carnivorous and Omnivorous Fish with Varying Physical Characteristics” are to develop cost-effective feed formulations using locally sourced ingredients with varying physical characteristics (i.e. sinking or floating pellets), and to evaluate these feeds in a carnivorous fish (‘moi’ - Polydactylus sexfilis) and an omnivorous fish (‘Nile tilapia’ - Oreochromis niloticus). For the omnivorous fish, the diets’ formulation assessed will be based on local feed developed from previous CTSA-funded research. Feed cost in aquaculture, when combined with increasing costs of fishmeal and fish oil, presents a formidable challenge for feed mill operators and fish farmers, and there is strong incentive to identify alternative ingredients to reduce feed cost.  Understanding the effectiveness of alternative feed ingredients and feed pellet physical characteristics on a commercial scale is essential for the economic viability and sustainability of the local, regional, and global aquaculture industry. For over a decade, Oceanic Institute of Hawaii Pacific University (OI) and University of Hawaii (UH) researchers have identified and analyzed potential feed ingredients from the Pacific region. With previous CTSA funding, important advances in the development of feed for moi and tilapia have been made, but no study have been conducted on the variation of extruded pellets physical characteristics (i.e. sinking or floating pellets) of diets formulated with local ingredients and their impact on fish production. Thus, additional research is needed to make a more cost-effective local diet that promotes good growth and survival, and is optimized to match the fish’s favored feeding behavior. In addition, the development of local feeds for other important aquaculture species cultured in the Pacific region (e.g. kahala, shrimp, and abalone) are important next steps for the expansion of local agriculture and aquaculture sectors in the region. Accordingly, this research will be focusing on developing local feeds for carnivorous and omnivorous fish, with two extruded pellet physical characteristics (sinking vs. floating) utilizing moi and Nile tilapia as models for a carnivorous and an omnivorous species, respectively.