Location: Subtropical Plant Pathology Research
2021 Annual Report
Objectives
The U.S. has tremendous capacity for meeting the domestic demand for seafood by expanding aquaculture in federal waters and land-based recirculating systems. As the largest importer of seafood products, expanding domestic production will reduce our reliance on imports and the trade deficit. This project will support the U.S. aquaculture industry by developing technologies that will ensure a steady supply of warm water marine fish seedstocks that are optimized for commercial production.
1. Develop year-round spawning strategies for captive broodstock and larviculture methods for seed production of marine finfish.
2. Develop methods for genetic improvement of warm water marine finfish for optimum production efficiency.
3. Increase understanding of fish physiology and enhance production efficiency through improved management strategies.
Approach
Aquaculture producers need access to seedstocks that are available year-round and optimized for the production environment. Research is needed to develop seedstocks that are bred for maximum production efficiency and have minimal impacts on the environment and native populations. Research in the disciplines of genetics, fish health, nutrition, reproductive biology, and physiology will contribute to the development of seedstocks that meet these criteria.
Progress Report
This is a report of the 2nd year (FY2021) progress of a multi-year USDA-ARS collaborative research partnership with Florida Atlantic University’s Harbor Branch Oceanographic Institute (HBOI). The project began during the 2nd year of a standard USDA project planning cycle. There is no existing standard 5-year plan. A 5-year plan will be established “on cycle” after the first 4 years of the project. During these initial 4 years while the project is being “stood up,” annually prioritized experiments are being determined in consultation with industry stakeholders and USDA-ARS.
For Oobjective 1, researchers at HBOI partnered with local fish farms to complete a study of the tolerance of larval pompano in salinities lower than seawater. Microbiological samples of water revealed that several micro-organism species known to negatively impact marine fish, including Florida pompano and red drum, were in greater abundance at lower salinity. Examination of fish tissues is underway to determine if stress, due to pathogen exposure, is increased at the lower salinities. The results also suggest the micro-organisms are influenced by the feeding schedule; these results will lead to better feeding strategies. Biochemical analyses of recently hatched pompano (from hatch to 24 days after hatch [DAH]) were also conducted. There were no differences in larval health from below normal to normal salinity. Changes in the fish were related to developmental changes (i.e., age DAH) rather than salinity. The relationship between health of Florida pompano larvae (from 1 to 24 DAH) and salinity were principally seen in the gill tissues. The preliminary results show changes (e.g., epithelial lifting, or mucous cell hyperplasia) that are likely associated with stress at low salinity.
Three trials were conducted by ARS researchers in Fort Pierce, Florida, to evaluate clam and hemp processing by-products as ingredients for marine fish diets. An initial study, at the request of industry partners, ARS researchers in Fort Pierce, Florida, evaluated the availability of nutrients from these products to marine fish. Both products indicated the nutrients were highly available to the fish.
Both by-product meals were studied for suitability as new fish feed ingredients. Clam by-product meal at 20% of the diet was achieved without loss in growth while maintaining the health and well-being of juvenile pompano. A report is being generated to submit to the Food and Drug Administration (FDA) and the Association of American Feed Control Officials (AAFCO) for approval as a new animal feed ingredient for marine fish diets.
Hemp protein was investigated by ARS researchers in Fort Pierce, Florida,to determine its effects on growth and performance in marine fish. Results indicate that formulation of diets meet the nutritional requirements for the economical production of Florida pompano and red drum are possible. Final recommendations on dietary safety levels are underway by collaborative researchers at Florida A&M University. Dissemination to the marine fish aquaculture community will be presented in February 2022.
Almaco Jack juveniles were transported to the University of Miami (UM) to study energetic needs for normal development. Following acclimation, the fish were tested to determine if they had functional swim bladders; required for normal development. Those that did were used to study their energetic needs. Oxygen use while swimming in a range of temperatures encountered by Almaco Jacks in both ocean- and land-based aquaculture was examined. The data is being analyzed, by researchers at UM. This research is invaluable for marine fish producers facing uncertainties of climate change.
A Mississippi student was recruited to study nutrient use during pompano early development. Pompano broodstock were acquired in August 2020, quarantined, and given 6 months to achieve final reproductive status. Broodstock were fed defined diets to understand what determines reproductive quality and success. They are being conditioned for spawning to see these dietary effects. This study will determine the amount of time needed to change the composition of eggs for improvements. Greater reproductive success will increase the efficiency of producing seedstock for marine fish farms.
For Objectives 1 and 3, in collaboration with Mote Marine Laboratory (MML), Sarasota, Florida, Almaco Jack broodstock ovaries were sampled to determine the reproductive status and egg composition. The fish were fed only threadfin herring for 35 days. This pre-experimental phase demonstrated the dietary effect on egg composition prior to feeding 2 commercial pelleted diets. Eggs from multiple spawning events were sampled to document fish egg and oil droplet shape and diameter to see the amount of time needed to favorably change egg composition after a diet change.
A 30 m3 broodstock tank at the UM, is being equipped with a RAS to house Almaco Jack broodstock. Broodstock have been attained and once mature, will be induced to spawn using environmental conditioning techniques for defining reproductive success studies. This broodstock population at UM provides information to marine fish farmers for Almaco Jack production in the U.S.
Researchers at HBOI along with Hubbs Sea World Research Institute evaluated broodstock diets to determine the best one for developing high quality eggs and better development of California yellowtail larvae. A freshly thawed squid/sardine mixture and two different commercial pelleted broodstock diets were fed to determine the specific nutritional needs of California yellowtail to enhanced health and well-being of juvenile fish. Biochemical analysis to determine nutrient content of the diets and their suitability for enhancing egg development, larval health, and survival was completed. Nutrients captured in the eggs were compared to those present in the diet during the 6 month reproductive season. Nutrient profiles were more variable in eggs from the squid/sardine diet than from the two pelleted feeds. The squid/sardine diet contained more required dietary fatty acids than the two pelleted diets. This information helps larval fish producers to design feeding strategies that will increase the efficiency of producing seedstock marine fish.
For Objective 2, a new method was developed by ARS researchers in Fort Pierce, Florida, to identify the genetic variations in wild populations of Florida Pompano. This method allows for genetic sequencing at a fraction of the cost of other methods and will allow selecting parents with desirable production traits (e.g., growth and disease resistance). This will be used to develop a genetics-based selective breeding program for improved seedstock.
The genomes of two species closely related to Florida pompano (Permit and Palometa) have been determined. These species coexist in similar locations as the Florida Pompano and have similar diets but grow at different rates. Permit are up to 10x heavier than Florida pompano, but Palometa are only 1/6th their weight. This genetic information allows for the identification of growth related genes desired for a genome-informed selective breeding program.
In collaboration with Purdue University, RNA from 3 DAH Florida pompano, with either “normal” or abnormally curved spines are being evaluated by ARS researchers in Fort Pierce, Florida, to determine the effects of water salinity on development. The Florida pompano gene information has been referenced to the genome of the golden pompano with > 84% success. The golden pompano genome however does not yet have a full reference set available through existing genetic databases hindering our understanding of the differences. ARS researchers in Fort Pierce, Florida, are obtaining similar or better success with Greater Amberjack.
A fish bioinformatics lab for Objectives 1, 2 and 3 was outfitted at HBOI. This lab provides tools to evaluate enhanced survival, faster growth, efficiency, and well-being of seedstock for farm productivity. Standard operating procedures for the isolation and identification of the viruses, bacteria, and parasites that affect pompano were developed. Disease organisms identified as a major risk by the marine fish farmers are the focus. New techniques for early diagnosis, novel therapeutics, and control methods for diseases are under development. This includes the cause, spread, and pathology of bacteria, viruses, and parasites that affect the health status of tropical and subtropical warm water marine fish such as Florida pompano, red drum, and Almaco jack, among the many species of interest for culture by U.S. fish farmers. This information will serve as a background reference for the development of standard operating procedures that will be used by new and future fish farms.
Accomplishments
1. Demonstrated growth, survival, and health of Florida Pompano larvae raised in decreasing salinity. Production of juvenile fish used for stocking marine finfish farms has been restricted to coastal lands, unless large additions of salt are used, which can be costly to both the farmer and the environment. ARS researchers in Fort Pierce, Florida, in collaboration with local fish farmers determined the growth, survival, health and well-being of early-life stage Florida pompano raised in lower salinity than found in the ocean. After evaluating the effects of lower salinity on the bacterial composition, fish health, stress, and well-being, it was determined that the salt in the environment can be reduced by half without any effects on growth or well-being of the fish. This accomplishment demonstrates Florida pompano, and likely other highly prized marine fish can be reared in a lower salinity than originally believed. The benefits include opportunities for a greater number of U.S. marine finfish farmers, and a potential cost savings for producing these juveniles, especially in areas without direct seashore access.
2. Established high-quality reproductive stocks of high-value warm water marine finfish. To support the expanding warm water marine finfish aquaculture industry, prospective farmers require a steady, consistent supply of high-quality animals. ARS researchers in Fort Pierce, Florida, have established a Florida pompano reproductive stock to produce a steady, high-quality source of fish for these farms by defining and improving the production of high-quality eggs and juveniles to support the industry. A consortium of like-minded researchers from Florida Atlantic University, Fort Pierce, Florida; the University of Miami, Coral Gables, Florida; Hubbs Sea World, San Diego, California; and Mote Marine Laboratory, Sarasota, Florida, established methods for identifying attributes to increase survival, faster growth, and well-being of early-stage Almaco Jack, Florida pompano and other closely related species highly prized by U.S. consumers. This includes understanding the effects of temperature and oxygen availability on the energy needs of the fish during production, under both current and potential climate change conditions. Benefits to marine finfish producers and consumers are better production efficiencies and a better tasting product brought to market safer, faster, and more economically.
3. Determined nutritional value of new feed ingredients for Florida Pompano. Cost and ecological sustainability of feeds for farm raised fish dictate the success or failure of fish farms, therefore finding new and less expensive ingredients, such as leftover products from making other useful goods, is essential. ARS researchers in both Fort Pierce and Tallahassee, Florida, have determined the availability of nutrients to Florida pompano from the parts of clams not used for human consumption, and from production of hemp fibers for the textile industry. Both products indicate the growth-promoting and healthy nutrients in them are highly available to Florida pompano suggesting they should make very good supplements to marine finfish feeds. These efforts created nutrient availability values provided to fish feed manufacturers to develop and market more sustainable fish feeds. Benefits from this research include information for fish farmers and feed manufacturers to produce more sustainable fish feeds, and potential new revenue streams for two additional industrial manufacturing processes.
4. Demonstrated algae oil in fish diets as a viable alternative to fish oil. Due to economic and sustainability issues, associated with expensive and diminishing supplies of fish oil used in feeds for farmed fish, alternatives are in high demand. Vegetable oils associated with agriculturally based products (e.g., corn, soy, olive, canola, etc.,) do not contain the right components to meet marine finfish needs (especially those that normally eat fish) for normal growth and well-being or provide the heart healthy nutrients needed by American consumers. ARS researchers in Fort Pierce, Florida, along with other partners demonstrated that oils from algae, processed under the right conditions can fulfil that need. The right algae, produced under the right conditions, can produce the same oil products that result in highly desired marine fish that are fed fish oil diets. Benefits to the American consumer include a safer, better tasting product with all the heart-healthy components consumers seek.
5. Hosted an industry/stakeholder informational workshop. To ensure U.S. marine finfish aquaculture industry and taxpayer interests are met, it is essential to inform interested parties on programmatic progress and seek input on future programmatic direction. ARS researchers in Fort Pierce, Florida, in coordination with the U.S. Warm Water Marine Finfish Aquaculture Advisory Committee, hosted a workshop to disseminate programmatic progress and seek input for future programmatic direction. The workshop successfully encouraged the ongoing dialogue between project researchers, industry, and other stakeholders. The documented outcomes were productive and instrumental in underscoring ongoing stakeholders needs and refining new industry challenges. The benefits to industry and the U.S. consumer are a very directed and focused effort to increase production efficiencies and a better tasting product brought to market safer, faster, and more economically.
6. Produced an industry requested publication on the status of U.S. Marine finfish aquaculture. Over 85% of the seafood Americans eat is imported, half is produced through foreign aquaculture; therefore, expanding aquaculture in the U.S. would reduce our $16.8 billion seafood trade deficit. Following a series of workshops, surveys, and presentations by the foremost experts in the U.S. a publication on the status of readiness for numerous species and priorities for removing barriers to commercialization were collated, written, and edited by ARS researchers in Fort Pierce, Florida, to spur domestic growth in marine finfish aquaculture. The articles provide up-to-date scientific and technical knowledge needed to sustainably produce safe and nutritious fish that will lead to the creation of new economic opportunities through aquaculture in rural, urban, coastal, and inland communities. The benefits to U.S. Marine finfish aquaculture are innumerable and can be found in the publication at: https://onlinelibrary.wiley.com/toc/17497345/2021/52/3
Review Publications
Mejri, S., Riche, M., Wills, P., Tremblay, R., Audet, C. 2021. Essential fatty acid requirements in tropical and cold-water marine fish larvae and juveniles. Frontiers in Marine Science. 8:680003. https://doi.org/10.3389/fmars.2021.680003.
Rexroad Jr, C.E., Rust, M.B., Riche, M., Wills, P., Davis, M. 2021. Opportunities for US Marine Finfish Aquaculture. Journal of the World Aquaculture Society. 1-8. https://doi.org/10.1111/jwas.12791.
Weirich, C., Riley, K., Riche, M., Main, K.L., Wills, P.S., Illan, G., Cerino, D.S., Pfeiffer, T.J. 2021. The status of Florida pompano, Trachinotus carolinus as a commercially ready species for U.S. Marine Aquaculture. Journal of the World Aquaculture Society. 52(3):731-763. https://doi.org/10.1111/jwas.12809.
