Location: Subtropical Plant Pathology Research
2024 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 Five years (FY2020-FY2024) of 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. During these initial years while the project is being “stood up,” annually prioritized experiments were determined in consultation with industry stakeholders and USDA-ARS. This allowed the project to rapidly respond to stakeholders’ immediate and evolving priority needs.
Key accomplishments during the five years of the project included successfully reconditioning office workspace to house USDA-ARS scientists and staff on the HBOI campus under lease agreement 57-6034-19-027. Extensive renovations and upgrades to labs and fish husbandry areas for USDA and HBOI scientists were done to provide an environment suitable to conduct experiments.
Broodstocks of Florida Pompano (HBOI), Red Drum (HBOI and MOTE Marine Lab), Almaco jack (U. Miami), California Yellowtail Jack (HSWRI) and Atlantic croaker (HBOI) including both hatchery-reared, and wild-caught fish were established, and a draft genome of Florida Pompano was sequenced and the protein coding gene set (a.k.a., Transcriptome) was completed.
In addition, the nutritional requirements of Florida Pompano broodstock was determined. The growth, survival, and health of Florida Pompano larvae raised in decreasing salinity was demonstrated, and the nutritional value of new feed ingredients for Florida Pompano and Red Drum including byproducts of clam processing, hemp, and black soldier fly meals was determined. Whole wheat grain as a good source of carbohydrates for farm raised Florida Pompano was also determined, and reduced live feed requirements for Florida Pompano by up to 80% of prior levels with new experimental larval diets. Scientists also established that the wild population of Florida Pompano off the Atlantic Coast of FL and the Gulf Coast of FL are genetically similar suggesting they are one population.
Scientists developed a Rapid Disease Diagnostic Tool for Marine Fish and demonstrated algae oil in fish diets as a viable alternative to fish oil.
The scientists produced an industry requested publication on the status of U.S. Marine finfish aquaculture. the publication at: https://onlinelibrary.wiley.com/toc/17497345/2021/52/3.
Research established methods for the successful out of season spawning of Yellowtail broodstock and demonstrated the effects of copper sulfate on the microorganisms within a tank following treatment with copper sulfate.
Further work established an appropriate substitution of fish meal by black soldier fly meal (BSFM) for Red Drum.
Successful and consistent egg quality production from California Yellowtail (S. dorsalis) and that they selectively retain essential lipids from their diets after just 10 to 19 days of feeding was established, and extended out-of-season spawning techniques and methods for larval rearing of the species by 5 months.
Researchers at HBOI-FAU partnered with local fish farms in Florida to address the knowledge gap around live feed substitution in larvae. The objective of this collaboration was to test the potential of a novel commercial compounded diet to replace and eliminate the need for rotifers and/or Artemia as live feeds for early feeding of Florida Pompano. The diets are designed to reduce the need for rotifers and Artemia by at least 50%. Hatching success was estimated at each farm (~72% to 96%, depending on the farm. A control group and 3 live feed replacement levels of replacement were tested. 18 days following hatch (18 DPH), the control group showed the highest weight gain followed by the 50% for rotifers and Artemia group. At 29 DPH, the control group also showed the highest weight gain. Fatty acid results showed a relatively similar pattern among all the groups. However, the essential fatty acid DHA was highest in the 80% replacement of Artemia at 18 DPH. Replacing live feeds with formulated diets allows the production of high-quality Florida Pompano.
Researchers at HBOI-FAU collaborated with ARS researchers to test the resilience of seedstock to extreme low oxygen levels. Fertilized eggs of Florida Pompano and Red Drum were incubated in two different dissolved oxygen (DO) levels; severe (20% DO saturation), moderate (50% DO saturation and normal (100% DO saturation). Eggs and larvae were sampled at 24-hours post-fertilization to assess performance. Florida Pompano embryos were susceptible to moderate levels of oxygen, leading to low hatching and performance. Red Drum embryos exhibited a higher tolerance to low oxygen conditions, with performance effected only at the lowest oxygen levels (20% DO saturation). This is relevant for stakeholders to understand how closely they should monitor oxygen levels in incubation tanks, with implications for environmental monitoring for wild populations.
Researchers at HBOI-FAU, USDA-ARS, and Purdue University also examined molecular responses of Florida Pompano larvae maintained under different salinity conditions, as low as 5 parts per thousand. Tissue samples were collected for evaluating potential effects on molecular changes.
Researchers at HBOI- FAU and USDA-ARS in collaboration with the University of Maine, Orono conducted a 10-week feeding trial on juvenile Florida Pompano to evaluate the effects of different dietary carbohydrate sources on growth, health parameters, and carbohydrate utilization in Florida Pompano. An adequate carbohydrate source would increase protein and lipid efficiency, reducing feed cost and ammonia release to the environment. Five diets with the same protein, lipid, and energy contents were fed to Florida Pompano. Results indicated that whole wheat grain resulted in optimal growth and efficiency in juvenile Florida Pompano. Fish fed whole wheat grain flour also maintained an adequate health status. Gene expression, including pathways for carbohydrate utilization and microbial communities were affected. This study indicated that whole wheat grain flour is the most suitable dietary carbohydrate source for Florida Pompano.
Researchers at HBOI-FAU and USDA-ARS in collaboration with Stratium, LLC, the Florida Costal Conservation Association and Duke Energy Crystal River Mariculture Center assessed the effects of replacing fish meal (FM) with black soldier fly meal (BSFM) in diets of juvenile Red Drum. Five diets with the same protein and lipid levels containing different black soldier fly meal (BSFM) inclusions were evaluated and the best growth, feed conversion efficiency and health status were in fish fed with the diet at 25% BSFM. The palatability of BSFM indicated it was an acceptable fish meal replacement in Red Drum diets up to a 25% inclusion.
Researchers at HBOI-FAU, USDA-ARS, in collaboration with Auburn University conducted a series of growth trials to compare a high soy-low animal meal diet to a commercial feed formulation, to evaluate the efficacy of new soy-products in diets for the Florida Pompano. In addition, the requirement for methionine, an essential amino acid for fish was determined. Three trials were performed to better understand how soy processed in different ways impacts the growth, feed efficiency, and health of Florida Pompano. Higher levels of soy are possible than previously thought with no signs of effects on health status.
Researchers at HBOI-FAU, USDA-ARS, in collaboration with Florida A&M University evaluated diets with graded hemp meal with 5, 10 and 15% inclusions with and without taurine supplements in Florida Pompano and Red Drum. Hemp meal had no adverse effect on either species, and survival was high. Growth of both Pompano and Red drum was affected by replacing fishmeal with hemp. For Florida Pompano and Red Drum, 5% hemp meal diet supplemented with taurine presents a nutritional balance.
Researchers at HBOI-FAU, USDA-ARS in collaboration with Mote Marine Lab (MOTE) evaluated the link between the diet of Red Drum broodstock and the quality of their eggs and larvae. Eggs and larvae were collected from a series of 12 mass spawning events across 3 broodstock populations over an 8-month period. Comparisons are being made against those eggs collected from spawning wild females.
Researchers at HBOI-FAU, USDA-ARS in collaboration with Hubbs Sea World Research Institute (HSWRI) evaluated the dietary impact on egg quality in California Yellowtail broodstock showing that overall fatty acids from two experimental diets with differing fat profiles were fully incorporated in the eggs 9 days following the diet switch.
Researchers at HBOI-FAU, USDA-ARS in collaboration with HSWRI refined out-of-season spawning techniques for California Yellowtail. The spawning season was extended, doubling the spawns from 34 in 2023 to 76 in 2024. Swim bladder inflation trials were conducted that showed that surface access was necessary.
HBOI-FAU and USDA-ARS researchers in collaboration with Aquaco Farm (Fort Pierce, FL) collected genetic samples from 56 wild broodfish and nearly 1,000 captive-bred offspring for bioinformatics analysis. Aquaco assigns offspring to a uniquely coded tracked cohorts with known parents and spawn dates. They regularly conduct size gradings on each cohort through grow-out and cull smaller fish. We collected samples of both sizes at each culling event to track separate cohorts from hatch to harvest. Length and weight were also recorded for each size class. A subset of samples representing five cohorts are being used to discover single sites on genes linked to growth for marker-assisted selection.
Accomplishments
1. Black soldier fly meal is a partial substitute for fish meal. Fish meal is a principal feed ingredient in diets for species like Red Drum; however, use of fish meal is increasingly environmentally and economically unsustainable requiring alternative substitutes. ARS researchers in Fort Pierce, Florida established an appropriate substitution level of a novel feed ingredient (black soldier fly meal) by evaluating growth, animal efficiency, diet acceptance, and indicators of fish health in Red Drum. This accomplishment establishes the suitability of black soldier fly as a fish feed ingredient drawing much interest from insect growers, fish feed manufacturers, and fish farmers. The industry is using the data to seek Association of American Feed Control Officials (AAFCO) and the US Food and Drug Administration (FDA) approval of black soldier fly meal as an approved feed ingredient in fish feeds.
2. California Yellowtail broodstock research. Seedstock (e.g, larvae) have long been a bottleneck in successful aquaculture operations, and the production of quality seedstock is known to hinge on broodstock nutrition and transfer of nutrients to the eggs. ARS Researchers at Fort Pierce, Florida, in collaboration with Researchers at Hubbs Sea World Research Institute in San Diego, California demonstrated successful and consistent egg quality production from California Yellowtail (Seriola dorsalis) following the feeding of different broodstock diets. Seriola dorsalis eggs can selectively retain essential lipids from their diets during periods of dietary deficiencies and that overall fatty acids from diets are incorporated into eggs after just 10 to 19 days of feeding, resulting in hardier, more robust seedstock. This accomplishment assists producers in determining the optimal timing for transitioning from a regular diet to a more specialized spawning diet to improve egg quality to meet the growing demand in the US marine aquaculture industry.
3. California Yellowtail year-round spawning. A consistent year-round supply of seedstock (e.g, juveniles) has long been a bottleneck in successful aquaculture operations, resulting in insufficiency of juveniles for restocking to maintain farm operations at an economical scale. ARS Researchers at Fort Pierce, Florida, in collaboration with Researchers at Hubbs Sea World Research Institute in San Diego, California. Established out-of-season spawning techniques and methods for larval rearing for California Yellowtail, where the spawning season was extended by 5 months. As California Yellowtail this accomplishment provides another tool to increase farm management practices by giving consistent access to high quality seedstock year-round. This provides consumers, grain growers, feed manufacturers, and fish farmers greater access to markets.
4. Florida Pompano Culture Manual published as part of outreach efforts. Outreach to all stakeholders, wherever it lies on the value chain, is an imperative function to provide stakeholders with timely information to improve profitability of their industry. A workshop on all aspects of the culture of Florida Pompano was held on the campus of Harbor Branch Oceanographic Institute, Fort Pierce, Florida, hosted by Researchers from FAU-HBOI, USDA-ARS and others to provide recent and timely information to stakeholders, across representing multiple stakeholder groups. A product of this workshop was a manual titled, Cultural Manual for the Florida Pompano Trachinotus carolinus (Linnaeus, 1766), covering all aspects of Florida Pompano culture. This product is anticipated to increase the probable success of not only Florida Pompano, but other US marine finfish producers as well.