Thomas Losordo

Our goal is to enhance the economic competitiveness and environmental sustainability of farming established and emerging finfish cultivars in North Carolina (NC), including the striped bass and its hybrids and the Atlantic sturgeon. We aim to deliver new biotechnologies for improving gamete quality and early identification of gender, stress management and enhancement of growth, and the reuse, treatment and disposal of fish farm water and effluents. Our specific objectives are to: 1) reveal how the major system for uptake of yolk precursors by the ovary functions and to discover how this system is disrupted in female striped bass producing poor quality eggs; 2) develop a minimally invasive and practical method for identifying the gender of Atlantic sturgeon farmed for caviar so that males can be culled early in the production cycle; 3) discover how cortisol, a stress hormone, may influence the endocrine system regulating normal growth in hybrid striped bass (HSB) and accelerated growth induced in this species; 4) develop a disposal and treatment system for HSB pond effluents via their application onto land planted with various tree species; and 5) improve recirculating aquaculture system (RAS) technology and identify system requirements and costs for production of market-sized HSB in a RAS. Objectives 1-3 will be met via investigation of reproductive and growth physiology emphasizing specific genes, proteins and hormones, and objectives 4-5 will be achieved through aquaculture engineering and economic modeling efforts. Findings of the research will be widely disseminated to stakeholders in the NC and national aquaculture industries.

Our goal is to develop new technologies for enhancing sustainable production of warmwater fish culture. An array of detailed studies in the areas of reproduction, growth regulation and water reuse will be conducted. Specifically, these studies will be focused on 1) discovering the root causes of poor egg quality in striped bass, 2) understanding the mechanisms of feed intake and growth in hybrid striped bass, 3) management of specific ion deficiencies in recirculating systems used for the culture of flounder, and 4) optimizing production technology for hybrid striped bass culture in closed recirculating systems. The results of this work will play an important role in contributing to the sustainable development of aquaculture in North Carolina

With NOAA fisheries promoting the use of catch shares to manage our fisheries in this country there will be big changes ahead for the commercial sector. Individual transferable quotas (ITQ?s) are a form of catch share program. Fishermen are given a percentage of the total allowable catch (TAC) to harvest through the year as they see fit. It is widely known that percentage awarded to each fisherman will be less and maybe much less than their historical yearly average. Fisherman will have to get a higher price per pound to maintain a viable business. For the black sea bass market, live fish is one potential option. In order to hold live fish, systems similar to those used in aquaculture must be designed and managed to ensure the health of the fish after catch. Previous FRG projects using black sea bass in aquaculture systems concentrated on developing diets to grow legal wild caught black sea bass to a larger size for a premium price (98-AM-09, 03-AM-07), and explored various salinity and density regimes for culture of wild fish (00-AM-05). While effective, fish culture, rather than simply holding fish, requires additional filtration, system management, the addition of feed, and higher start-up costs. Hence, although a premium price could be obtained from a larger fish, production costs are also higher and must be considered in an operation. Fish holding systems are simpler in design, as fish are not fed during the holding period. Wastes (ammonia) generated in these systems originate only during the first three days after stocking fish, during which time fish are purged. Hence, the difference in managing a holding system compared to that of a true culture system is the timing and amount of ammonia produced. In culture systems, fish feed is typically added to the system twice daily, generating ammonia on a consistent basis. In contrast, holding systems experience a pulse of ammonia during the first 3 days after stocking, minimizing thereafter. Therefore, in order to successfully design and manage a holding system for fish (in this case the black sea bass), it is necessary to identify the timing and amount of ammonia production after stocking. Purposes (objectives) of the project: 1) To determine the amount of ammonia produced (mg ammonia per Kg of fish) and timing of production by black sea bass after stocking into a holding system. 2) Establish guidelines for biological filtration management during periods of stocking and removing fish from the system.

Growth of warmwater fish culture in North Carolina has slowed over the last several years. This is due in part to the relatively high production costs, which limits sale of fish to higher-value white tablecloth restaurants and ethnic markets. Hybrid Striped Bass (HSB) in particular have high production costs, use high volumes of water, and also have notoriously lower feed efficiency relative to other established cultivars. Additionally, effluents from HSB farms are a cause of concern among the citizenry and environmental regulators. Our goal is improve the production efficiency of the North Carolina warmwater fish culture industry through a better understanding of the fundamental mechanisms controlling growth and feed intake, and to establish methods to improve production efficiency and environmental sustainability of HSB and recirculating systems. Preovulatory atresia, the breakdown and resorption of ovarian follicles and oocytes, is a major factor limiting production of high quality eggs in striped bass and other farmed fishes. We recently discovered that, at the onset of atresia, striped bass ovary produces a hatching enzyme (choriolysin) that degrades the zona radiata, which gives rise to the egg envelope or chorion, allowing the granulosa cells to enter the ooplasm and phagocytize its contents. We aim to develop procedures whereby expression of the gene encoding choriolysin or morphological correlates thereof can be detected in females so that they can be reproduced before significant damage to their follicles and oocytes occurs. We will evaluate the role neuropeptide Y, an appetite stimulating hormone, plays in regulating the hyperphagic response observed during states of accelerated or compensatory growth (CG) in HSB. NPY expression will be assessed in animals exhibiting low, normal and elevated (compensatory) growth and feed consumption. We will also assess NPY regulation by other hormones putatively involved in appetite and energy balance as well as the potential actions of NPY in regulating the endocrine (growth hormone/insulin-like growth factor) growth axis. Different water conservation practices and post-harvest treatments of HSB ponds will be evaluated to determine the effects on Biochemical Oxygen Demand (BOD) and chlorophyll-á levels in the effluents. Three different EPA-approved chemicals will be evaluated along with a non-chemical control (2-4 week waiting period) to reduce BOD below 10 mg/L and chlorophyll-á below 40 µg/L to meet effluent water quality standards. The development of these practices would improve the environmental sustainability of HSB pond production in accordance with State water quality standards. A geotextile bag will be evaluated as part of a seawater recirculating system that is designed to completely eliminate discharge from these systems. The development of this technology would effectively allow the culture of seawater animals in inland areas and drastically reduce the potential environmental impact of seawater recirculating systems.

Soybean meal (SBM) is the number one world-wide source of protein in animal diets, accounting for over 75% of plant proteins fed. Its relatively high yield, high crude protein content, stable supply and cost are reasons for its significant used in fish diets. Further, SBM is becoming a more important component in feeds as fish meal originates from the wild harvest of ocean fish, which has been viewed by some environmental groups as unsustainable, when considering worldwide expansion of aquaculture. In North Carolina, SBM is used at varying levels in diets for all commercially cultured species including hybrid striped bass (HSB), catfish, rainbow trout, flounder, tilapia, and freshwater prawns. Dietary levels depend on the feeding strategy for the species, with lower levels being fed to carnivorous fish, and higher levels fed to omnivorous fish. Since feed costs represent 40-70% of production costs for aquaculture operations, the use of high quality, lower cost ingredients such SBM can assist in reducing feed costs. Further, identifying methods to increase SBM usage in carnivorous species such as HSB could further reduce costs for fish producers while simultaneously providing greater marketing potential for soybean products, supporting the goals of the NC Soybean Producers Association. To that end, we intend to determine the effect of increasing SBM levels in HSB diets on growth, feed efficiency, and digestive tract morphology.

This work will involve writing a new publication for the Southern Regional Aquaculture Center (SRAC) which will improve understanding of the operation of recirculating aquaculture systems. 'Starting' a biofilter refers to the process of establishing nitrifying bacteria on the biological filter media so that these bacteria may begin processing the nitrogen-based waste produced by the organisms cultured in the recirculating system. The publication will be available to North Carolina citizens and the general public and will be an educational aid to those who operate recirculating aquaculture systems.

This work will involve re-writing and updating the current Southern Regional Aquaculture Center (SRAC) Fact Sheet Number 456 to reflect current understanding of the economics and operation of recirculating aquaculture systems. In addition, the current spreadsheet will be updated to include additional economic factors and analysis, making it more suitable for use in a business plan. The revised publication and companion spreadsheet will be available to North Carolina citizens and the general public and be suitable as a tool for recirculating aquaculture business planning.

Specialized diets for fish are the single largest cost of production in most commercial finfish aquaculture operations. These diets, in the past, have contained large quantities of fish meal as a source of protein. Recently, environmental groups worldwide have raised concerns that fish stocks are being depleted due to the harvesting of the oceans for the production of fish meal. In response, aquaculture researchers have and continue to develop feeds with low or no fish meal as a protein source. Dr. Marc Turano, Sea Grant Aquaculture Specialist has developed one such diet. He has just completed testing the diet with Hybrid Striped Bass at the new Marine Aquaculture Research Center in Marshallberg, NC. The diet had completely replace fish meal as a source of protein with soybean meal and a small amount of animal bi-products protein. We believe that, based upon Dr. Turano?s studies with Hybrid Striped Bass, his no-fish meal diet offers promise for Tilapia nursery culture. We propose to conduct an evaluation of the ?Turano Diet? at the NC State Fish Barn. More specifically we propose to have Astor Farms, Inc. deliver to the Fish Barn 20,000 fingerling tilapia from the supplier used in past studies at the Fish Barn and currently being used by the Fresh Keepers Cooperative of which Astor Farms, Inc. is the latest member. We will stock and grow the fingerlings on a commercial diet until they are large enough (approximately 5 grams) to be fed the experimental diet. Once on the experimental diet, the fish will be grown to an average individual weight of between 80 and 100 grams. We predict the total trial to take 12 weeks. The trial will be terminated at 12 weeks regardless of the average weight of the fish. NC State personnel will be responsible for conducting this experiment at the Lake Wheeler Road Fish Barn. A sample of 10% of the population will be collected every two weeks to assess the average weight of the population. Water quality and feed conversion data will also be tracked.

Our goal in this project is to leverage the considerable investment from Golden LEAF Foundation and others into an extension/demonstration project designed to jumpstart the first southern flounder farms in the U.S. and indeed the world. These funds will allow us to establish a full microsatellite (gene) library for southern flounder and the final side-by-side growth evaluations that are needed to achieve certification of this improved strain.Our work on purging or polishing protocols will establish a practical means of achieving consistent sushi-grade product that will fetch the highest price in the marketplace. These protocols will have been developed with the highest degree of sophistication in sensory discrimination and consumer preference analysis.

Hybrid striped bass (HSB) production in ponds is a highly water-intensive operation. Current production practices require annual pond draining to harvest and move fish and avoid infestations by the parasitic yellow grub (Daniels 2005). These practices create large volumes of effluent at certain times of the year and have led to complaints by local residents about stream eutrophication and habitat degradation. Effluents released from the North Carolina HSB farms are slow-moving and drain into wide and shallow estuarine coastal creeks that empty into the Pamlico Sound ? part of the nutrient sensitive Tar-Pamlico River Basin (sub basin No. 7). Based on our monitoring of the water quality of the HSB effluents, the only means to satisfy these complaints and to bring the producers into compliance with effluent standards is to drastically reduce or eliminate effluents from the farms. The information generated from this work will be the first commercial-scale analysis of water conservation practices for HSB. The current need for this information by state water quality regulators, and therefore the HSB producers, is acute and critical. Without an objective evaluation of these practices the producers face an uncertain future squeezed between the need to satisfy regulatory and environmental concerns and the need to maintain the profitability of their business. We expect that the development and adoption of water conservation measures by HSB producers will reduce the environmental impact of the farms and ensure the continued economic sustainability of this important industry in North Carolina and nationally.