Steven Hall PhD

Aquaculture, the rearing and harvesting of organisms in water environments, is a rapidly expanding industry that now produces more seafood than all wild caught fisheries worldwide. This inevitable growth must be steered towards sustainable production practices, which requires intensive monitoring in areas that are difficult and potentially dangerous to access. The vision of this project is to improve the efficiency and sustainability of near-shore aquaculture production through integrating a flexible, customizable, multi-task vehicle fleet, consisting primarily of unmanned aerial vehicles (UAVs) and unmanned surface vehicles (USVs), with a biologically-relevant framework for accelerated prototyping. This project will use oyster production along the Eastern US shoreline as a case study and testbed.

The seafood trade deficit in the United States (U.S.) has exceeded $16 billion and 80% of the seafood products consumed in the U.S. are of foreign import, half of which are from aquaculture operations. There is no appreciable aquaculture of white-fleshed marine species such as the striped bass (Morone saxatilis) in the country. Development of major marine aquaculture species would aid in strengthening a domestic seafood industry and bring economic prosperity to coastal and rural communities of the U.S. Relative to other marine fishes, the striped bass is a well-suited candidate to meet the market demand as it is well-recognized and studies show good growth in fresh, brackish, and marine environments. The target market size for the fish has been identified as between 3 and 5 lbs, and value-added striped bass in seafood markets and grocery stores already retail at $18.00 per lb for fillets, with a potential farm-gate value of $4.00-$5.00 or more per lb. The feasibility of commercializing striped bass at a fairly rapid pace is already established as well, to the extent that a commercial farm currently exists in northern Baja California Mexico (Pacifico Aquaculture) that produces millions of lbs of fish annually into a market large enough to include chain-grocery stores. Research on reproduction, genetics, culture, and feed requirements of striped bass have already been established and the industry shows great potential if the following barriers are addressed: successful intensive larval rearing and year-round juvenile production capabilities. This project will expand the influence of the Sea Grant StriperHub to also include the Great Lakes/Midwest regions (Ohio Sea Grant and Illinois-Indiana Sea Grant). Development of intensive larval rearing methods will allow for more widespread availability of domestic striped bass seedstocks for fingerling production and commercial growout in these regions more distant from the base of StriperHub at the Atlantic Coast. Striped bass will be commercially farmed and available in markets by the conclusion of the project and major venture and angel capitalists will be sought for industry upscaling to improve the overall domestic seafood supply in the U.S.

The goal of this project is to generate an improved understanding of sediment dynamics at and around the Rachel Carson Reserve. Specifically, this project seeks to: quantify the magnitude and change in sediment loading rates and sources; determine the mechanisms through which the changing geomorphology of the Beaufort Inlet drives shoreline change and sediment dynamics; and examine the degree of geomorphological change caused by extreme storm events and its impacts on the habitat and infrastructure resiliency. The project team will collaborate with the N.C. Coastal Reserve and NERR to produce: a functional numerical model that can be used to simulate sediment dynamics at and around the Reserve; and maps that show the variability of vulnerability indexes within the Reserve to pronounced geomorphological change and its impact on sediment dynamics. It is envisioned that results of this project will generate: an improved understanding of how the interaction between extreme storm events, river systems, and coastal processes impact sediment dynamics at and around the Reserve; refined decision making and management for engineering practices at the Beaufort Inlet; and an improved understanding of the impact of sediment dynamics on the vulnerability of coastal habitats and infrastructure for informing effective resilience planning.

Fishmeal (FM) and fish oil (FO) are important ingredients for aquaculture fish feed formulations due to their contribution of essential amino acids and polyunsaturated fatty acids, respectively. These are beneficial in many ways. However, these ingredients are relatively expensive and rely on wild-caught seasonal harvests. Therefore, we are interested in examining the potential of converting sustainably-sourced salmon processing by-products (fish trimmings and skins; SBP) into components of aquaculture fish feed. In North Carolina, 25,000 lbs of SBP is generated each week from a facility that processes aquacultured salmon into smoked fillets. Currently, most of the SBPs are taken to a landfill. We propose the utilization of SBPs to produce FM and FO that will be substituted in standard feed formulations at 25, 50, 75, and 100% of normal commercial ingredient (FM and FO) inclusion rates. Fish feeds will be formulated to be complete diets, isonitrogenous and isocaloric. Feed ingredients and formulated fish feeds will be analyzed for physicochemical properties related to quality during a 6-month accelerated shelf life study. Initial feed palatability studies will be conducted using a commercial marine aquaculture species (striped bass). Then we will test the efficacy of formulated feeds during 18-week fish feeding trials.

The modern availability of novel data analytics and cost-effective high-performance computing creates unique opportunities to tap into the wellspring of potential offered by big data for creating decision-making tools that inform sustainable agroecosystem management. When coupled with climate, land use, and policy-related data streams through analytics, long-term monitoring data can be applied to develop data-driven decision-support tools designed for land and water resource managers, but foundational research is needed to develop such data-rich decision-support platforms. As a case study, this research will develop a data-to-decision pipeline for nearshore water quality management in support of shellfish agroecosystem protection. Shellfish growing areas are regularly screened for coliform bacteria to inform on-the-fly decision-making by regulators who are evaluating the sanitation of cultured shellfish, which has led to the accrual of a vast record of spatiotemporal bacterial observations. These national-scale data remain poorly explored and underutilized due to challenges associated with analyzing big, multi-scale data, but could be mined to develop critically-needed decision-support platforms.

The goal of this study is to address challenges related to feeding economically important cultured fish. The study is divided into 3 parts: 1) Feeding systems, 2) innovative inert feeds, and 3) Nutritional improvement with live foods. To address Objective 1 of the project, this proposal seeks to automate feeding of live feeds in aquaculture by developing an automated system for feeding Artemia to larval fish. Larval finfish often require live foods. One of the most popular larval foods is Artemia, often wild harvested from the Great Salt Lake or other areas. However, there are limits to the wild harvest, so alternatives that can reduce dependency on Artemia could have positive ecological but also economic implications. Part of the challenge is the methods by which feeding is done at specific culture stages, requiring customized hand feeding at substantial labor and expertise. It is likely that, in the interests of keeping larval finfish alive, excess feeding occurs. This is often, then, an inefficient and expensive endeavor that merits improvement. Automation in aquaculture has a significant history. Over the years, there have been substantial improvements in equipment and monitoring, especially of water quality, but also of feeding, fish health, utility management and other areas. Some commercially available systems can feed pellets (e.g. AKVA akvasmart; Fish Farm; Pentair and other suppliers); or even pump solutions into fish tanks. However, automated feeding of live Artemia is still at a primitive state. What is needed is a liquid based, controlled flow system that allows high levels of survival as well as efficient movement of the Artemia to the feeding fish. This proposal would significantly improve automated Artemia feeding with a focus on precision dosing and at intervals required to meet the needs of the fish being cultured. This type of system can then be used to enhance the weaning process to inert feeds, thus reducing the amount of total Artemia used in larval culture and simultaneously removing significant labor costs and possible human error. Our team has personal motivation to reduce ����������������all night��������������� feeding of larval fish, thus enhancing human health and thought, and ultimately enhancing fish health and development. To address Objective 2 of the project, a series of investigations are proposed in two parts. 1) Evaluate the efficacy of commercial larval microdiets as successful replacements for Artemia as early/first feeds of important marine and freshwater fish species, including southern flounder, striped bass and red drum, as well as freshwater zebrafish. The diets will be chosen which represent the breadth of products currently marketed as Artemia replacement diets and fed according to the unique requirements of the species in the trial. 2) Evaluate the role of texture as a significant palatability variable in fish microdiets. This poorly understood, yet critical, physical characteristic will be examined by comparing textural elements of the commercial diets in part 1 with experimental diets we will manufacture using innovative marumerization technology. The experimental diets will be based on a larval diet formulation known to be successful for both freshwater and marine species. The overall project will evaluate both the commercial and experimental diets based on attraction and ingestion, in concert with a comparison of physical characteristics focusing on texture. The results of this work will provide unique insight into microdiet characteristics required for acceptance by larval fish by addressing physical constraints affecting palatability when compared to live Artemia. To address Objective 3 of the project, a series of investigations are proposed to nutritionally augment live food organisms already enriched with long-chain highly unsaturated fatty acids (HUFA), with potentially limiting nutrients such as ascorbic acid (vitamin C), vitamin E, taurine and nucleotides. Enrichment protocols will be developed for each of the nutrients mentioned previously to be augmented in controlled culture

The goal of this study is to address challenges related to feeding economically important cultured fish. The study is divided into 3 parts: 1) Feeding systems, 2) innovative inert feeds, and 3) Nutritional improvement with live foods. To address Objective 1 of the project, this proposal seeks to automate feeding of live feeds in aquaculture by developing an automated system for feeding Artemia to larval fish. Larval finfish often require live foods. One of the most popular larval foods is Artemia, often wild harvested from the Great Salt Lake or other areas. However, there are limits to the wild harvest, so alternatives that can reduce dependency on Artemia could have positive ecological but also economic implications. Part of the challenge is the methods by which feeding is done at specific culture stages, requiring customized hand feeding at substantial labor and expertise. It is likely that, in the interests of keeping larval finfish alive, excess feeding occurs. This is often, then, an inefficient and expensive endeavor that merits improvement. Automation in aquaculture has a significant history. Over the years, there have been substantial improvements in equipment and monitoring, especially of water quality, but also of feeding, fish health, utility management and other areas. Some commercially available systems can feed pellets (e.g. AKVA akvasmart; Fish Farm; Pentair and other suppliers); or even pump solutions into fish tanks. However, automated feeding of live Artemia is still at a primitive state. What is needed is a liquid based, controlled flow system that allows high levels of survival as well as efficient movement of the Artemia to the feeding fish. This proposal would significantly improve automated Artemia feeding with a focus on precision dosing and at intervals required to meet the needs of the fish being cultured. This type of system can then be used to enhance the weaning process to inert feeds, thus reducing the amount of total Artemia used in larval culture and simultaneously removing significant labor costs and possible human error. Our team has personal motivation to reduce ����������������all night��������������� feeding of larval fish, thus enhancing human health and thought, and ultimately enhancing fish health and development. To address Objective 2 of the project, a series of investigations are proposed in two parts. 1) Evaluate the efficacy of commercial larval microdiets as successful replacements for Artemia as early/first feeds of important marine and freshwater fish species, including southern flounder, striped bass and red drum, as well as freshwater zebrafish. The diets will be chosen which represent the breadth of products currently marketed as Artemia replacement diets and fed according to the unique requirements of the species in the trial. 2) Evaluate the role of texture as a significant palatability variable in fish microdiets. This poorly understood, yet critical, physical characteristic will be examined by comparing textural elements of the commercial diets in part 1 with experimental diets we will manufacture using innovative marumerization technology. The experimental diets will be based on a larval diet formulation known to be successful for both freshwater and marine species. The overall project will evaluate both the commercial and experimental diets based on attraction and ingestion, in concert with a comparison of physical characteristics focusing on texture. The results of this work will provide unique insight into microdiet characteristics required for acceptance by larval fish by addressing physical constraints affecting palatability when compared to live Artemia. To address Objective 3 of the project, a series of investigations are proposed to nutritionally augment live food organisms already enriched with long-chain highly unsaturated fatty acids (HUFA), with potentially limiting nutrients such as ascorbic acid (vitamin C), vitamin E, taurine and nucleotides. Enrichment protocols will be developed for each of the nutrients mentioned previously to be augmented in controlled cultu

Probiotics and prebiotics are live microbes and microbial substrates, respectively, which may be supplemented in the diet to alter the gastrointenstinal tract microbiota to favorable species such as lactic acid bacteria. These supplements have been shown in some terrestrial and aquatic species to confer numerous favorable effects on production efficiency, immuno-stimulation, disease resistance and gut morphology. Very little effort has been directed to evaluation of the efficacy of these products during hatchery rearing from the early larval stages through metamorphosis to the fingerling stage. Two commercially available probiotics (Aqua Blend from bio-CAt and Bactocell from Lallemand0; and two commercially available prebiotics (GroBiotic-A from IIC and SiLO Health from BASF) will be administered. In vitro clinical trials and in vivo hatchery trials will be conducted. Data will include length, weight gain, feed palatability and survival. Results of the project will be distributed to aquaculturists through refereed journal publication, articles in trade journals, conferences and a Southern Regional Aquaculture Center fact sheet.

This study aims to investigate the effectiveness of the cyanobacterial species Synechococcus elongatus UTEX 2973 for bioremediation of aquacultural wastewater. S. elongatus 2973 is the fastest growing cyanobacterial species with 51% carbohydrate content of the dry cell weight at stationary phase under nitrogen replete condition (Song et al., 2016; Tan et al., 2018). The cyanobacterial biomass grown in the aquaculture wastewater will be used to produce sugar via enzymatic saccharification, which can further be used to make various bioderived value-added products. An increase in complex cellular carbohydrates, mostly glycogen content in cyanobacteria, will result in an increase in sugar production. CO2 uptake and the nutrient contents such as nitrogen and phosphorus will optimized to increase the carbohydrate accumulation in S. elongatus 2973 cells. To complement the experiments, stoichiometric metabolic modeling of S. elongatus UTEX 2973 will be performed to predict the growth of the species and glycogen accumulation in biomass under different environmental conditions, such as at varying the CO2 uptake, nitrogen, and phosphorus consumption. Furthermore, the metabolic model of this strain will be used to predict optimal nutrient levels in aquaculture wastewater for carbohydrate accumulation. Current research is limited due to the insufficient utilization of cyanobacterial carbohydrates during sugar production. Therefore, this proposed research also aims to develop a process that can ensure maximum recovery of cyanobacterial carbohydrates by investigating the effect of metal ions on sugar production via enzymatic saccharification of biomass. Incorporating aquaculture effluent in cyanobacterial cultivation as a growth medium can reduce the cost of sugar production by replacing costly growth media with a waste product.

Scour is the most common cause for bridge failures in the U.S. Previous studies have suggested that bivalve colonies reduce local erosion through different processes, and that bivalves feature a high resistivity to strong flow. With today������������������s advancements in bivalve aquaculture design and management, the PIs hypothesize that bivalve aquacultures are suitable as a self-sustained scour mitigation method, and are proposing to investigate the geotechnical aspects of this hypothesis. Specifically, the PIs are proposing to test the following working hypotheses: H1) The presence of bivalve colonies reduces local scour and erosion. H2) Bivalve colonies form morphologies applicable to scour protection design. H3) Bivalve adhesive protein increases sediment strength and decreases erodibility. H4) Bivalve dislodgement from soil surfaces occurs as ����������������block failure��������������� for single bivalves, but becomes irrelevant for erosion issues in the case of bivalve groups. These hypotheses will be tested through an interdisciplinary and multi-method approach featuring: (i) field investigations at two bivalve colonies in Virginia and North Carolina, (ii) an analytic comparison of bivalve colony morphology and flow resistivity to modern scour protection designs, and laboratory tests investigating (iii) the change of sediment strength and erodibility resulting from mixing bivalve adhesive protein with sediment and (iv) soil failure behavior during bivalve dislodgement. The research team is composed of experts in geotechnical and hydraulic engineering, as well as in aquaculture design and management. The PIs will be supported by international collaborators and experts in etho-hydraulics from the Technical University of Darmstadt who will contribute through a preliminary numerical simulation of the field sites to the project.