Aquaculture (NP 106) Annual Report for 2007 

Introduction 

The mission of the Aquaculture National Program is to conduct high quality, relevant, 

basic and applied aquaculture research, to improve the genetic foundation of 

domesticated aquaculture species, and to conduct technology transfer in order to enhance 

the productivity and efficiency of US producers, and the quality of seafood and other 

aquatic products. Jeff Silverstein, Ph.D, National Program Leader (NPL), Aquaculture, 

began managing the program in October 2008. 

Dr. Brian Small with the Catfish Genetics Research Unit in Stoneville, MS was honored 

as the recipient of the “Distinguished Early Career Award in U.S. Aquaculture” presented 

by the United States Aquaculture Society, a chapter of the World Aquaculture Society. 

Veterinarian and experienced epidemiologist, Dr. Julie Bebak joined the Aquatic Animal 

Health Research Unit in Auburn, AL. Her background and experience brings new 

strengths to this unit. Dr. William Hershberger, the director of the National Center for 

Cool and Cold Water Aquaculture, one of the larger aquaculture research centers for 

ARS, retired in September, 2007 after eight busy and productive years. His replacement 

is currently being sought. 

The Aquaculture National Program completed the fourth year of the five year National 

program cycle in Fiscal Year (FY) 2007. The Aquaculture National Program currently 

includes 27 core research projects supported by 60 scientists located at 15 research sites 

throughout the country. The ARS research budget for the Aquaculture Program FY 2007 

was $ 32 million (NTL). 

Construction began on the broodstock facility for the National Center for Cool and Cold 

Water Aquaculture. This facility is expected to be completed in early 2008 and will hold 

the rainbow trout brood fish for the Center’s selective breeding program. 

Fish health inspections have been conducted on breeding populations of Atlantic salmon 

at the Franklin, Maine location and rainbow trout at the Leetown, WV location making 

them eligible for certification status. All populations have been free of reportable 

pathogens thus far. 

Scientists in the Aquaculture National Program were well recognized nationally and 

internationally with over 40 invited presentations. ARS Aquaculture scientists were 

successful in applying for extramural grants with 9 awards being made totaling over 

$450,000.00. 

 

Scientists within the National Aquaculture Program were very active in their fields during 

FY 2007, with more than 90 articles in peer-reviewed scientific journals. Many of the 

discoveries and findings were published in the popular press to reach customers and 

stakeholders, including 99 articles in trade journals and book chapters. Technology 
transfer activities for the National Aquaculture Program included 4 invention disclosures, 

13 new Cooperative Research and Development Agreements (CRADA) and Material 

Transfer Agreements (MTA). 

The following section of the report summarizes high impact research results addressing 

objectives in the current national program action plan. 
Genes regulating egg development. Improving egg quality, reflected by better 

fertilization and hatching rates is important for the trout industry. Research conducted at 

the National Center for Cool and Cold Water Aquaculture examined the localization and 

time course of gene expression of a suite of genes thought to regulate oocyte 

development in the stages just prior to spawning. This work has shown differences in the 

location of expression of several key genes, some growth factors are expressed in the 

follicle cells surrounding the oocytes whereas other key growth factors are predominantly 

expressed in the oocyte. Additionally, this work has revealed the time course of events 

leading up to spawning. These data suggest that these peptide dynamics may be critical to 

the process of oocyte development and therefore may be important for egg quality. 

(National Program 106 and Performance Measure III.C.1) 

Scientific Publication: 

Weber, G.M., Moore, A.B., Sullivan, C.V. 2007. In Vitro Actions of Insulin like Growth 

Factor-I on Ovarian Follicle Maturation in White Perch (Morone americana). General and 

Comparative Endocrinology 151, 180-187. 

Identification of new rainbow trout immune genes. Infectious disease is a significant 

factor hindering aquaculture and a better understanding the fish immune system is 

required to improve health and disease resistance. Studies at the National Center for 

Cool and Cold Water Aquaculture identified a family of forty-four new tumor necrosis 

factor (an important group of immune system genes) gene sequences from rainbow trout 

and other fish species. Comparison of the protein sequences and chromosomal locations 

allowed us to identify which genes were related to those found in mammals and which 

were unique to fish. We developed methods for measuring gene expression in rainbow 

trout tissues. These studies have led to a better understanding of how the fish immune 

system functions and how it differs from that of mammals. The newly developed gene 

detection methods will advance studies on gene expression and functional analyses in 

fish. (National Program 106 and Performance Measure II.C.1). 

Scientific Publication: 

Glenney, G.W., Wiens, G.D. 2007. Early Diversification of the Tumor Necrosis 

Superfamily in Teleosts: Genomic Characterization and Expression Analysis. Journal of 

Immunology, 178:7955-7973. 

Disinfection in recirculating fish culture systems. Pathogens and other microbial 

populations can accumulate and compromise fish health in fish culture systems that 

recirculate water. Scientists at The Conservation Fund’s Freshwater Institute 

(Shepherdstown, WV) determined the process requirements necessary to achieve fullflow disinfection of recycled water using ozonation followed immediately by ultraviolet 

irradiation. The entire recirculating flow could be effectively disinfected when the ozone 

dose was controlled in a feed-back loop using probes that measured either dissolved 

ozone concentration or oxidation reduction potential. Thus, combining ozone with 

ultraviolet irradiation in a recirculating system can prevent the accumulation of most fish 
pathogens and significantly reduce the risk of spreading fish disease. These findings will 

be used to produce more biosecure aquatic production systems that sustain healthier and 

more growth promoting environments. (National Program 106 and Performance Measure 

VI.B.1). 

Scientific Publication:

Sharrer, M.J., Summerfelt, S.T. 2007. Ozonation followed by ultraviolet irradiation 

provides effective bacteria inactivation in a freshwater recirculating system. Aquacultural 

Engineering 37, 180-191. 

Weaning rock sole onto artificial feeds with chemical cues. Getting larval fish to switch 

to artificial feeds from the live feeds they begin feeding on, is difficult. Scientists at the 

NOAA Fisheries in Manchester, Washington in collaboration with scientists at the 

University of Idaho Hagerman Fish Culture Experiment Station, the University of 

Alaska’s Fishery Industrial Technology Center in Kodiak, Alaska and the Subarctic 

Agricultural Research Unit in Fairbanks evaluated different Alaska fish processing 

byproducts for their ability to stimulate the weaning of rock sole (Lepidopsetta spp.) 

larvae onto prepared feeds. L-alanine, Artemia culture water and red salmon stickwater 

(the soluble protein fraction resulting from protein meal processing) were chosen as the 

chemical cues, and inert metal oxides were incorporated at known proportions into the 

feeds to measure their consumption. When red salmon stickwater was added to the 

culture medium before weaning, the fish were more likely to take up the microparticulate 

food on the first and second days post-weaning than fish that were not given the chemical 

cue. These results indicate the potential for using stickwater or compounds derived from 

stickwater in fish larvae production. Use of this material may enhance the larval survival 

of marine fish larvae. (National Program 106 and Performance Measure VII.F.1). 

Scientific Publication:

Sathivel, S., Bechtel, P.J., Prinyawiwatkul, W. 2006. Physicochemical and Rheological 

Properties of Salmon Protein Powders. International Journal of Food Engineering. Vol. 2 

: Iss. 2, Article 3. Available at: http://www.bepress.com/ijfe/vol2/iss2/art3

Need for taurine in plant protein diets for rainbow trout. The use of plant proteins in 

aquafeeds is growing. Although rainbow trout have some capacity for taurine 

biosynthesis from sulfur amino acid precursors, taurine has been identified as a potential 

limiting nutrient in plant-based diets for rainbow trout. Methionine is a precursor sulfur 

amino acid that can be supplemented to animal feeds more cost effectively than taurine. 

Research conducted at the Hagerman Fish culture Experiment Station by ARS scientists 

in collaboration with the University of Idaho tested the efficacy of supplementing 

methionine and taurine separately and in combination on production performance of 

rainbow trout. Using metabolite profiling technologies this experiment determined that 

bioconversion of methionine to taurine was limiting and supplementing taurine was 

necessary. The impact of this research is to verify the need for taurine supplementation 

in plant-based diets for rainbow trout and continue to refine plant-based aquafeeds to 
reduce dependence on fish meals. (National Program 106 and Performance Measure 

IV.D.1). 

Scientific Publication: 

Gaylord, T.G., Teague, A.M., Barrows, F.T. 2006. Taurine supplementation of all-plant 

protein diets for rainbow trout oncorhynchus mykiss.. Journal of the World Aquaculture 

Society. 37:509-517. 

Gaylord, T.G., Barrows, F., Teague, A.M., Johansen, K.A., Overturf, K.E., Shepherd, 

B.S. 2007. Supplementation of taurine and methionine to all-plant protein diets for 

rainbow trout (Omcorhynchus mykiss). Aquaculture 269:514- 525. 

Improved treatment for Asian tapeworm in baitfish. Commercially raised fish infected 

with Asian tapeworms have limited potential for sale and therefore can be a detriment to 

the producer. The efficacy of bath treatments of praziquantel against these tapeworms 

was evaluated by scientists at the HKD Stuttgart National Aquaculture Research Center 

in heavily infected grass carp, and a 24-h bath treatment of 0.75 mg/L eliminated all 

tapeworms from the fish. The impact will be an economic benefit by allowing producers 

to ship their fish to states that require tapeworm-free fish. (National Program 106 and 

Performance Measure II.B.3). 

Scientific Publication: 

Mitchell, A.J., Hobbs, M.S. 2007. The acute toxicity of praziquantel to grass carp and 

golden shiners. North American Journal of Aquaculture. 69:203-206. 

Performance of low-salinity recirculating aquaculture system. Low-salinity recirculating 

systems can eliminate the need for marine aquaculture to be located near limited and 

expensive coastal land thereby expanding opportunities for marine aquaculture; however, 

little information exists regarding efficient operation of low-salinity recirculating 

systems. Juvenile Florida pompano were raised to market-size in a low salinity 

production-scale recirculating system by scientists at the ARS Sustainable Marine 

Aquaculture Project in Fort Pierce, FL. Pompano were reared for 300 days from 30 g to 

620 g, and the efficiency of ammonia removal, feed and waste particle removal, and 

oxygen, water, and energy use were monitored on the system components as increasing 

amount of feed inputs were used to maximize fish growth. The accomplishment provides 

culturists and engineers baseline performance and design criteria over a complete 

growout cycle for the construction of production-scale recirculating systems to produce 

market-size marine fish in low salinity. (National Program 106 and Performance Measure 

V.F.1). 

Scientific Publication: 
Weirich, C.R., Riche, M.A. 2006. Tolerance of juvenile black sea bass centropristis 

striata to acute ammonia and nitrite exposure at various salinities. Fisheries Sciences. 

72(5):915-921. 

Riche, M.A. 2006. Analysis of refractometry for determining total plasma 

protein in hybrid striped bass(Morone chrysops x M. saxatilis) at various 

salinities. Aquaculture. 264:279-284. 

Estimation of phenotypic and genetic (co)variances for economically important traits in 

catfish. Estimation of phenotypic and genetic (co)variances for economically important 

traits are required for development of a breeding program to produce superior catfish 

germplasm for release to catfish producers. Data were collected for growth, resistance to 

enteric septicemia of catfish (ESC, the most devastating disease for catfish production), 

and processing yield and resulted in heritability estimates of approximately 0.35, 0.10 

and 0.25, respectively. The best performing animals from families of the third generation 

of selection of a channel catfish line were selected as future broodstock based on an index 

for these traits. Selected broodstock were mated to produce another generation of 

families which are currently being evaluated for growth, resistance to ESC, and 

processing yield. This information is being used in a continued selection program to 

develop superior germplasm for release which will benefit producers, processors, and 

consumers. (National Program 106 and Performance Measure I.B.3). 

Scientific Publication: 

Bosworth, B.G., Wolters, W.R., Silverstein, J., Li, M.H., Robinson, E.H. 2006. Family, 

strain, gender, and dietary protein effects on production and processing traits of norris 

and NWAC103 strains of channel catfish, Ictalurus punctatus. North American Journal of 

Aquaculture 69:106-115. 

Peterson, B.C., Small, B.C. 2007. Effects of GH on Immune and Endocrine Responses of 

Channel Catfish Challenged with Edwardsiella ictaluri. Comparative Biochemistry and 

Physiology A 146:47-53. 

Reproductive efficiency among catfish strains. The spawning rate of catfish throughout 

the industry is low (~30%) and requires the stocking of an excess of broodfish to insure 

adequate numbers of juveniles are produced. Although breeding programs to improve 

channel catfish traits for commercial aquaculture exist, there is a lack of data on 

reproductive parameters related to spawning. In order to evaluate potential strain 

differences for reproductive traits, four selectively bred commercial strains of channel 

catfish were evaluated in a 12-month study, during which critical reproductive indices 

were measured, including various sex steroids, proteins, and enzymes. These data are 

being used to assess what controls reproductive success in channel catfish in order to 

develop tools to rapidly identify strains or individuals with greater reproductive potential. 

(National Program 106 and Performance Measure III.A.1). 

Scientific Publication: 
Barrero, M., Small, B.C., D'Abramo, L., Hanson, L., Kelly, A. 2007. Comparison of 

Estradiol, Testosterone, Vitellogenin and Cathepsin Profiles Among Twoyear- old 

Channel Catfish (Ictalurus punctatus) Females from Four Selectively Bred Strains. 

Aquaculture 264:390-397. 

Assess antibody and cellular immune responses against major fish pathogens. Disease is 

the major cause of fish loss. Knowledge of antibody and cellular immune responses is 

essential for the development of vaccines against major fish pathogens. The protective 

role of antibodies found in serum and mucus against the pathogens Streptococcus iniae, 

S. agalactiae and Ichthyophthirius multifillis was assessed. Antibodies from the blood of 

tilapia immunized against S. iniae and S. agalactiae protected naïve tilapia from infection 

with S. iniae and S. agalactiae, respectively. Mucus antibody from the skin of channel 

catfish immune to Ichthyophthirius prevented Ich infections. Research demonstrated that 

extracellular products of the streptococcal vaccines are important pro-inflammatory 

molecules that initiate the cellular immune response to streptococcal infections and 

vaccination. (National Program 106 and Performance Measure II.C.1). 

Scientific Publication: 

Klesius, P.H., Evans, J.J., Shoemaker, C.A. 2007. The macrophage chemotactic activity 

of Streptococcus agalactiae and Streptococcus iniae extracellular products (ECP). Fish 

and Shellfish Immunology. 22(5)443-450. 

Pasnik, D.J., Evans, J.J., Klesius, P.H. 2006. Passive immunization of nile tilapia 

(oreochromis niloticus) provides significant protection against streptococcus agalactiae. 

Fish and Shellfish Immunology. Vol 21 Issue 4 pages 365-371. 

Alternative protein sources and agricultural byproducts. As a result of the recent 

expansion and increase in ethanol production for fuels due to the shortage and rising cost 

of petroleum-based fuel, the distiller’s dried grains with solubles (DDGS) production in 

the U.S. has been estimated to greatly increase in the years to come. Thus, new uses for 

DDGS are needed. A feeding study indicated that, with lysine supplementation, at least 

40% DDGS can be included in catfish feeds as replacement of a combination of Soybean 

Meal (SBM) and corn meal on an equal protein basis without affecting their growth 

performance. Incorporating 20 to 40% DDGS with lysine also improved some immune 

parameters and the resistance of catfish to E. ictaluri. For tilapia, 30% DDGS can be used 

as a substitute for soybean and corn meal without requiring the addition of lysine. With 

lysine supplementation, DDGS can be included at 60% level as a total replacement of 

soybean meal without affecting fish growth and feed efficiency for tilapia. Dietary levels 

of DDGS, however, had no effect on immune response and resistance of tilapia to S. 

iniae. (National Program 106 and Performance Measure IV.C.2). 

Scientific Publication: 
Lim, C.E., Garcia, J.C., Aksoy, M., Klesius, P.H., Shoemaker, C.A., Evans, J.J. 2007. 

Growth Responses and Resistance to Streptococccus iniae of Nile Tilapia, Oreochromis 

niloticus Fed Diets Containing Distiller's Dried Grains with Solubles. Journal of the World 

Aquaculture Society. Vol. 38, No. 2. p. 231-237. 

The influence of multiple pathogens on fish was examined. The major cause of loss of 

production in aquaculture is disease, and simultaneous infection by multiple pathogens, 

concurrent infections (i.e. parasite and bacteria), are common in cultured fish. 

Gyrodactylus spp. (monogenetic trematodes) are common fish parasites that cause 

mechanical injuries on fish skin, and gills and lead to fish mortality under crowded 

conditions. Streptococcus iniae is a severe bacterial pathogen and causes heavy economic 

losses in aquaculture. No information was available on the association of Gyrodactylus 

and Streptococcus in tilapia. To better understand the invasion mechanism and control of 

the parasite, methods for culturing and maintaining Gyrodactylus under laboratory 

conditions and methods for harvesting the parasite were developed. Techniques were 

perfected to allow for survival of the parasite for about 3-4 day in the laboratory. 

Previous results suggested survival for only 24 h without a fish host. This technique was 

used to demonstrate that parasitism in tilapia with Gyrodactylus increased infection and 

mortality following exposure to S. iniae. The mechanical injury from the parasite 

apparently provided a portal of entry for the bacterium. Study results also suggest that the 

parasite harbored viable bacteria and may be a vector for transmission. This model will 

enable research and improve outcomes when facing concurrent infections. (National 

Program 106 and Performance Measure II.D.3). 

Scientific Publication: 

Xu, D., Shoemaker, C.A., Klesius, P.H. 2007. Evaluation of the link between 

gyrodactylosis and streptococcosis of Nile tilapia, Oreochromis niloticus (L.). Journal of 

Fish Diseases. 30: 233-238. 

Evans, J.J., Klesius, P.H., Pasnik, D.J., Shoemaker, C.A. 2007. Influence of natural 

trichodina sp. parasitism on experimental streptococcus iniae or streptococcus agalactiae 

infection and survival of young channel catfish ictalurus punctatus (rafinesque). 

Aquaculture Research. Volume 38, Issue 6:664-667.