EPIDEMIOLOGY AND DISEASE MANAGEMENT FOR AQUATIC SPECIES CULTURED IN WEST ALABAMA

<b>Project Methods</b><br> Environmental Epidemiology Factors Associated with Common Diseases Epidemiology research studies focusing on environmental parameters will be conducted on farms in west Alabama. The epidemiology research will be conducted using a questionnaire to determine factors such as feeding practices, dissolved oxygen concentration, fingerling suppliers, water quality parameters at the time of the disease outbreak, etc. Determining environmental and management components correlated with disease outbreaks will assist in the development of alternative management strategies that may minimize environmental factors associated with disease outbreaks. The farms in west Alabama differ in size and water sources (runoff and low salinity artesian wells). The design of the questionnaire will need to be tailored to the production facilities of interest. Additionally, in cooperation with an aquaculture Economist, risk assessment models will be developed. Our ability to conduct the epidemiology studies in a timely manner is enhanced by the fact that the AFFC is the primary laboratory for disease diagnosis in aquatic animals in west Alabama. Producers either bring fish samples in for disease diagnosis or laboratory personnel go to the farm in the Mobile Fish Health Laboratory (MFHL). The MFHL is equipped with all the necessary equipment to diagnose diseases on-site. It also has a refrigeration unit that can be used to store samples for viral analysis when back at the AFFC. Therefore, samples, water quality, disease identification and the questionnaire can be completed during the disease outbreak. Various organisms, but primarily birds, have been shown to transfer diseases from pond to pond in laboratory studies. Development of field studies to examine the impact birds have on disease transmission will be conducted. This portion of the research will be carried out in cooperation with personnel from the USDA Wildlife Damage Unit.Development of Management Strategies to Reduce Disease Outbreaks Aquaculture production management research will be carried out on farms using several different culture systems including commercial ponds, intensively aerated ponds, split ponds, or in-pond raceway systems. Experiments will be conducted either in the field (on-farm) or in existing tank systems at the AFFC. The AFFC is equipped with several tank systems for holding fish and for carrying out replicated research with both fish and crustaceans. Currently, the AFFC has six holding tanks (200-gallon capacity), a 12-tank partitioned aquarium system (15-gallon aquariums with a partition down the middle dividing each aquarium into two equal 7.5-gallon halves), a 24-tank recirculating system (20-gallon aquaria) and a 20-tank recirculating system (50-gallon tanks). These systems can be used to carry out studies on the effect of feed, water quality, and density on disease outbreaks in a variety of warmwater aquaculture species. The AFFC is also equipped with nets, seines, 4×4 trucks, trailers, and hauling tanks of various capacities to transport pond water and experimental animals to the facility.Additionally, a new building (Fish Shop) will be constructed at the AFFC. This building will enable us to conduct challenge studies, and controlled temperature studies. This building will double the research systems currently available at the center. The use of antimicrobial clays, probiotics and prebiotics in feeds to reduce the incidence of disease will also be examined. The diet formulations will be evaluated under controlled conditions in replicated tanks or aquaria. Once these studies are completed and if the results indicate it may reduce disease incidence then the diets will be used to assess their ability to reduce disease on actual farms in commercial ponds to complete the technology transfer process to the industry. Adoption of a new management technique requires commercial demonstration; the AFFC has a long history of on-farm verification/validation projects. In addition to trials carried out in commercial ponds, on-farm tanks, and aquarium trials at the AFFC facility, there is potential for conducting water quality studies on farms or setting up long-term water quality monitoring programs. The AFFC possesses a fully equipped wet lab and the capability to monitor dissolved oxygen, pH, temperature (HOBO loggers), total ammonia nitrogen, nitrite nitrogen, total hardness, total alkalinity, chlorides, salinity, carbon dioxide, and a vast array of other parameters. Catfish processing plants have expressed interest in improving the water quality of transport water in their hauling trucks, particularly as it relates to temperature, pH, and carbon dioxide. The water quality dynamics of alternative intensive pond-based production systems such as IAP have still not been widely studied. The effect of intensive feed management programs could also be evaluated in terms of short and long-term impacts on water quality. Currently, the PI is already involved with USDA ARS (Dr. Johnnie Shelley) examining the effects of blue-green algae in west Alabama catfish ponds on catfish livers. In addition, a research demonstration has been conducted using kaolin clay as an alternative control (by flocculation) of blue-green algae. In summary, this Hatch project will also seek funding to provide research-based information on water quality impacts on disease outbreaks and water quality management for warmwater aquaculture species.Low Salinity Aquaculture Production Presently, research on low salinity aquaculture production in west Alabama is centered on farmers raising the Pacific white shrimp. Small-scale tank and aquarium systems are available at the AFFC for conducting replicated research trials (see previously described systems) with shrimp. However, these systems can also be adapted to working with juvenile blue crabs or marine finfish species. While there is considerable interest by farmers and the general public in the culture of other marine species in low salinity water, current efforts by AFFC personnel prioritize supporting existing farmers already in production (marine shrimp producers). In addition to tank and aquarium systems, there is also potential for carrying out research and Extension demonstration activities using commercial size ponds on shrimp farms. On-farm studies can involve commercial feed demonstrations (previously described), research verification of production practices (previously described), and water quality monitoring. Collectively, the AFFC has the capability to carry out research and Extension demonstration activities by employing several different approaches to help solve problems for shrimp producers. During the project period (2020-2025), my research will focus on the objectives and will center around acclimation (and possible associated diseases), production techniques, water quality, and overall shrimp health. A significant amount of mortality occurs when shrimp farmers acclimate post-larvae from full strength seawater to the lower salinity of production ponds. The mortality can occur during acclimation or in the immediate weeks following this process. Currently, efforts are underway to examine shrimp throughout the process for signs of disease (bacteria, parasites, fungal and viral). The subjects of production techniques and water quality associated with disease will be recorded during each sampling period. In addition to these proposed experiments, other studies will be carried out to meet the needs of shrimp producers.