FRESHWATER FINFISH

Dr. James Rakocy (University of the Virgin Islands) – Aquaponics

A commercial-scale aquaponic system, developed at the University of the Virgin Islands (UVI), has been in operation for 9 years.  The UVI system, which has produced tilapia and a variety of vegetable crops, serves as a successful design model for the nascent aquaponic industry.  The system consists of four fish rearing tanks, two cylindro-conical clarifiers, four filter tanks, one degassing tank, six hydroponic tanks, one sump and one base addition tank.  Treatment processes consist of aeration, solids removal, denitrification, decomposition, degassing, nitrification and direct uptake of ammonia and other nutrients by plants.

Using advanced fingerlings (~50 g), Nile and red tilapia are cultured for 24 weeks.  Nile tilapia (Oreochromis niloticus) are stocked at 77 fish/m3 to produce 800-g fish while a red tilapia strain is stocked at 154 fish/m3 to produce 500-g fish.  The fish are fed a complete diet of floating pellets containing 32% protein. The fish are fed ad libitum for 30 minutes three times daily.  Production is staggered so that one fish tank is harvested every 6 weeks.  Production of leafy green vegetables is staggered to provide continuous weekly harvests while fruiting plants are cultured in batches.  Plant pests and diseases are controlled by biological methods.

The production capacity of the system is 5 mt of tilapia annually under optimum temperatures and feeding management.  Production averages 580 kg of tilapia every 6 weeks and 160 kg/m3/year of rearing tank space.  Examples of crop production capacity include annual yields of 1,400 cases of lettuce (24-30 heads/case) or 5 mt of basil or 2.9 mt of okra pods. 

Dr. Martin Schreibman (CUNY Brooklyn College) - “Urban Aquaculture: the Promises and the Restraints”

We will discuss the major ramifications of urban aquaculture development, using New York City as a model and template.  We define the parameters essential for successful aquaculture, as well as reflect on the problems that we face as we move urban aquaculture from concept to practice and to ultimate success. We envision closed, water-reuse systems (Recirculating Aquaculture Systems; RAS) as key to environmentally responsible, sustainable, intensive, and economically feasible aquaculture in metropolitan areas.  We suggest that research must play a major role in the development and application of technology, biological principles and socioeconomic feasibility, each of which are important entities for successful urban aquaculture development.  Furthermore, the future success of urban aquaculture is likely to depend upon support in the form of grants and subsidies, research, and access to capital.

MARINE FINFISH

Dr. Richard Lee (Skidaway Institute of Oceanography) – “Rapid Growth of Black Sea Bass with Geothermal Cooling, Solar Heating and Tilapia Diet”

Black sea bass (BSB; Centropristis striata) is a high value marine finfish along the eastern coast of the US that supports an important commercial and recreational fisheries. The decline in the landings and an increase in consumer demand for the BSB has provided the impetus for several studies on the commercialization of BSB aquaculture. Our studies have shown that rapid BSB growth (up to 2 lbs in one year) can be achieved by  (1) a diet of juvenile tilapia grown in green water raceways; (2) optimal temperatures (22-28oC) throughout the year provided by geothermal cooling in the summer and solar heating in the winter; (3) a recirculating systems with microbial mat/seaweed filter systems supplying seawater for the BSB that is low in ammonia and particulates.

Dr. Yonathan Zohar (University of Maryland Biotechnology Institute)- “Environmentally compatible, recirculated marine aquaculture: addressing the critical issues”

We report the development and feasibility of a land-based, recirculating marine aquaculture system (RAS) that is fully contained and biosecure, with nearly zero environmental impact as a result of over 99% water recycling. The system is species-generic, site-independent and devoid of environmental contaminants. It integrates aerobic and anaerobic microbial processes including, for the first time, anaerobic ammonium oxidation (anammox) and methanogenesis to eliminate toxic inorganic nitrogen compounds and organic solids, respectively, and generate methane as bio-energy to offset the energy cost of the operation. System viability is demonstrated by the production of several high-value marine fish at growth rates, food conversion values and production output beyond previously recorded levels for net-pen aquaculture.

Dr. Timothy Pfeiffer (USDA- Agricultural Research Service) – “Utilization of Low-head Technology for Inland Marine Recirculating Aquaculture Systems.”

Dr. Pfeiffer will present a brief overview of the USDA/ARS Sustainable Marine Aquaculture Project in Fort Pierce, FL and focus on the use of low head technology for inland recirculating aquaculture systems for the production of marine finfish. 

Dr. Steve Craig (Virginia Cobia Farms)- “Sustainable Aquafeeds for Cobia”

Dr. Craig will review nutritional research related to fish meal and fish oil replacement in aquafeeds for cobia, Rachycentron canadum. The overriding goal of this research was to develop truly sustainable aquafeeds for commercial cobia production. While most attention will be focused upon weight gain and feed efficiency ratios, some data will be presented discussing impacts on final product quality in fish fed diets containing higher levels of alternate proteins in replacement for fish meal. The presentation will summarize data from more than 18 feeding trials and over six years of nutritional research with cobia.

SHRIMP

Dr. Tzachi Samocha (AgriLife Research Mariculture Laboratory)- “U.S. Marine Shrimp Farming Program, biofloc shrimp system”

Shrimp farming is a major aquaculture industry in tropical and subtropical regions of the world. However, there are growing concerns regarding the sustainability of this industry. Discharge of nutrient rich effluent waters into low-recharge coastal areas can result in negative environmental impact. Use of super-intensive grow-out systems with high quality seed stock under biosecure conditions and limited water discharge can minimize losses and potential negative environmental impact.

The presentation describes super intensive production systems for the Pacific White Shrimp operated with limited discharge and used by The Waddell Mariculture Center, Bluffton, SC, and the Gulf Coast Research Laboratory, Ocean Springs, MS. In addition, the presentation provides a detailed description and results obtained by the AgriLife Research Mariculture Laboratory, Corpus Christi, TX where yield as high as 9.29 kg of marketable shrimp per 1 m3 of culture water were obtained with good growth, survival and FCR values under no water exchange.

The presentation will also include a short summary of the current and planned research activities by the AgriLife Research Mariculture Lab in the area of biodiesel production from microalgae using flue gas from power plants and the potential use of halophyte for aquaculture effluent water purification and for generation of biofuel.

Dr. David Kuhn (Virginia Polytechnic Institute and State University)- “Clear water system with biofloc from tilapia waste in pelleted feed”

Historically, aquaculture of Penaeus spp. has been limited to ponds in tropical coastal regions because these shrimp require salt water and warm temperatures. However, recent advances in recirculating aquaculture have made it more practicable to culture marine shrimp (Litopenaeus vannamei) using indoor recirculating aquaculture systems. For example, in southern Virginia, a recently constructed 30,000 square foot shrimp farm, Virginia Shrimp Farms Inc. (VSF), has been producing live shrimp for markets in New York City. University researchers from Virginia Tech have been collaborating with VSF on numerous research projects to help this industry increase production levels, while improving environmental sustainability.  Several of these projects will be covered in the presentation. Ultimately, it is anticipated that this research will enable the U.S. shrimp industry to competitively produce high quality shrimp, using environmentally sustainable technologies.

Dr. Shaun Moss (Oceanic Institute) – “An Integrated Approach to Sustainable Shrimp Aquaculture in the U.S.”

Dr. Moss will talk about the integration of four interrelated activities which are important to the development of a sustainable shrimp aquaculture industry in the U.S.  The four activities include: 1) the production of SPF, genetically improved shrimp; 2) an understanding of the microorganisms which support rapid shrimp growth, maintain acceptable water quality, and exclude opportunistic pathogens; 3) the development of exogenous feeds and feed management strategies which support both the shrimp and microorganisms; and 4) the establishment of biosecure production systems within which the shrimp, microorganisms, and exogenous feeds interact.

ECONOMICS

Dr. Terry Hansen (Auburn University) – “Overview of the Aquaculture Economics”

This presentation presents a bio-economic model that has been used to economically analyze United States Marine Shrimp Farming Program (USMSFP) research advances in the development of super-intensive, bio-secure, indoor, recirculating shrimp (Litopenaeus vannemei) production systems.  USMSFP research on these systems have been conducted at The Oceanic Institute (Hawaii), Waddell Mariculture Center (South Carolina), Texas A&M (Corpus Christi, TX), and the Gulf Coast Research Laboratory (Mississippi).  Each institution has developed unique production systems suitable to their locale.  Economic analysis has led researchers to focus on programs that increase the profitability of their systems by reducing operating and fixed costs.  Cash flows and enterprise budgets developed for USMSFP research trials are extrapolated to commercial-scale operations and financial indicators of profitability are calculated, such as cost of production, payback period, net present value, and internal rates of return.  Many factors affect the cost of production and financial feasibility results of these systems.  Sensitivity analyses of component aspects of the systems are conducted to identify key profitability factors, such as survival, shrimp price, stocking density, initial investment, growth rate, etc.  Researchers efforts to improve technologies have contributed small changes to many critical production components that are leading to reduced production costs and profitability.

Dr. David Guggenheim “Defining Next-Generation Aquaculture: Sustainable, Scalable, Profitable”

Closed-containment, land-based recirculating systems for aquaculture are not new.  However, the latest generation of this technology, highly integrated systems built from the ground up specifically for aquaculture purposes are distinct from land-based fish farms that employ tanks and pumps but have been assembled in an ad hoc fashion and fail to reach the efficiency, scalability and profitability of next-generation systems.

The latest next-generation closed-containment aquaculture systems represent a quantum leap forward, both as a lucrative and low-risk business venture as well as the most sustainable and efficient form of aquaculture today, with efficiencies more than 10 times conventional fish farms. Next-generation systems recirculate up to 99 percent of their effluent, have no discharge, use no chemicals or antibiotics, and can be sited close to market, resulting in a fresher product and dramatically lower transportation costs (food miles). Next-generation aquaculture systems are defined by the following attributes: fully-integrated, management system, total production control, reproducible results, ultra-high efficiency, competitive & cost-effective, low-risk & insurable and sustainable practices.

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