Group Summaries - Genetics

May 22-24, 2006 UF Tropical Aquaculture Laboratory Attendees: Steven Mims (KSU), Jesse Chappel (AU), Max Mayeaux (USDA), and Rebecca Lochmann (UAPB). Facilitator: Rebecca Lochmann (UAPB) SESSION SUMMARY: Kentucky State University (KSU) has a microsatellite library on paddlefish. (They are starting one on Macrobrachium.) KSU has sampled 5 different populations of paddlefish and see substantial {genetic} differences. In Ohio they found a unique population – still collecting samples. KSU wants to develop their own paddlefish broodstock – they use fish from the wild now. They will examine different stocks of fish and eventually link genetic traits with production characteristics (need to separate genetic from environmental influence). Ideally, they would like a faster-growing fish that matures at a small size for caviar production. They have created monosex populations using direct gynogenesis (heat shock):
·	Get 80 % females
·	Got caviar from 1^st monosex population – want to distribute fingerlings to farmers
·	Reservoir ranching of paddlefish can now be done in public waters (must verify which are defined as "public waters.")
·	Some interest in stocking paddlefish to improve water quality
John Liu (AU) has almost finished mapping the catfish genome. When he is done, he will need to explain practical applications to researchers and extension people. Rex Dunham (AU) is continuing work on channel x blue hybrid still. They are still doing manual strip spawning which is labor intensive and handling stress kills lots of broodstock. With hormone injection you can get consistent spawning of blue and channel CF, but would be better to determine natural causes of spawning induction and perhaps use natural cues to improve overall spawning success. Pheromones are a factor-concentration can be too high or too low for good spawning. Need more basic research to determine conditions for optimal spawning activity – Natural (pheromones) vs induced by hormone injections. Right now, have 50-60% more channel broodstock in MS than needed because natural inducers aren’t well known and aren’t exploited. Auburn may collaborate with Univ. of Pennsylvania to look at CF pheromones. This may be a fruitful area for an NRICGP proposal. At Auburn, new technology is refined and applied thru AETOS/Eagle Aquaculture – joint venture with Auburn – now testing a hatchery for hybrid CF – goal this year is 15 million fry.

June 5-7, 2005 Virginia State University Attendees: There were 20 participants from 11 institutions. Facilitator: Dr. Jimmy Avery SESSION SUMMARY: Jimmy Avery – MSU
·	A hybrid catfish production workshop was recently held at the NWAC. NWAC and USDA ARS Catfish Genetics Research Unit cosponsored the workshop. Principals were Brian Bosworth, James Steeby, Brian Small and Jimmy Avery. About 20 participants attended and received information on broodstock care, hormone injection, stripping, fertilization, and care of egg masses.
General group discussion
Max Mayeaux – USDA CSREES
·	Max reported on the National Animal Genomic Program and the National Aquaculture Germplasm program. Terry Tiersch at LSU is heading up the Germplasm program.
Jesse Chappel – AU
·	Liu at Auburn is continuing work on the catfish genome.

June 6-8, 2004 University of Arkansas, Pine Bluff Attendees: Ken Davis, USDA/ARS/SNARC; Steve Mims, KSU; Peter Woods, TAMU; Les Torrans, USDA/ARS/CGRU; Steve Pomerleau, UAPB; Dave Heikes, UAPB; Craig Tucker, MSU; and Nathan Stone, UAPB. Facilitator: Brian Small, USDA/ARS/CGRU Co facilitator: Sanatan Shreay, UAPB SESSION SUMMARY: Areas discussed:
·	Paddlewheel production
·	Improving channel catfish germplasm for release to industry
·	Identification of genetic markers for improved growth, fillet yield, and reproductive success
·	NWAC103 catfish
The session began with a formal introduction of all the participants and the type of research being conducted at their respective organizations. Dr. Mims began discussions with an overview the work currently being carried out on paddlefish production. Strategies for sex manipulation and determination were discussed. Both are important to the paddlefish industry, however, early sex determination is not possible at this time, and paddlefish have a long generation time. Dr. Davis and others agreed that this early sex determination of fishes is an area of research that may require more emphasis. Dr. Davis suggested that production of all male channel catfish might have the benefit of higher processing dress-out. He stated that a molecular technique for progeny sex determination would be useful. Dr. Small gave an overview of the ongoing research being conducted by the USDA/ARS/ Catfish Genetics Research Unit in order to improve channel catfish germplasm for release to the catfish industry. Researchers at the USDA/ARS/Catfish Genetics Research Unit are involved in identifying genes and gene products regulating immune response to common pathogens such as Edwardsiella ictaluri. Other research of interest to channel catfish production currently ongoing includes the identification of genetic markers for improved growth, fillet yield, and reproductive success. Dr. Tucker initiated a discussion on the NWAC103 channel catfish. This is a widely distributed, genetically improved strain of channel catfish that was jointly released by the USDA/ARS and Mississippi State University approximately 3 year ago. The NWAC103 catfish has a faster growth rate and consumes more feed, but studies indicate no improvement in disease resistance relative to other strains. Dr. Tucker suggested that perception of increased susceptibility to ESC by some farmers might be a management issue since the NWAC103 catfish consume more feed than other strains. He mentioned that new management schemes might be needed to take full advantage of the NWAC103 catfish. Another key area that emerged out of the discussion was the issue of licensing and keeping a new strain of fish genetically pure if released to the public. The session was concluded with a general discussion on patenting rights of the NWAC103 catfish.

March 19-20, 2001 Mississippi State University Attendees: William R. Walters, Geoffrey C. Waldbieser, Brian Small, and Brian Bosworth , USDA/ARS CGRU; Don Freeman and Kenneth Davis, USDA/ARS/SNARC; Bill Simco and Don Ourth, UMemphis; Allen Davis, Auburn; Tom Hill, UT. Facilitator: Not available SESSION SUMMARY:
·	Bill Wolters, Geoff Waldbieser, Brian Small and Brian Bosworth summarized the genetics research at the USDA/ARS Catfish Genetics Research Unit. The research unit has an integrated multi-trait applied breeding program that utilizes traditional quantitative genetics methods integrated with molecular genetics. A brief summary was made on the development, evaluation and release of the NWAC103 catfish line to commercial producers along with the molecular genetic basis for the fish certification program. A first generation catfish genetic linkage map has been completed and will be utilized in the breeding program to increase the efficiency of genetic improvement for traits with low heritability such as disease resistance or traits that involve sacrificing the fish for measurement such as dressout percentage. Future plans are to have a multi-trait selection program for growth, feed consumption, disease resistance, and dressout percentage in a single catfish line and integrate marker assisted selection into the breeding program. Introgression of blue catfish genes into channel catfish to produce a breeding line with natural reproduction is on-going.
·	Ken Davis and Bill Simco summarized their research progress on the development of sex-reversed catfish lines to produce 100% male offspring with faster growth rates. Their research in cooperation with the USDA/ARS lab in Stoneville has also led to the development of a gynogenetic catfish line that has been useful for genetic linkage mapping and immunology research.
·	Don Freeman and Ken Davis summarized preliminary research plan to develop a hybrid striped bass breeding program at the Stuttgart Research Center.
·	Research Discussions initiated at approximately 8:45 am and ended at 10:15 am.

March 29-30, 2000 Louisiana State University Attendees: Dr. Marty Fuller-MAFES; Dr. David Morrison-LSU AgCenter; Dr. Terry Tiersch-LSU AgCenter; Dr. Ken Davis-U Memphis; Dr. Jeff Silverstein-USDA/ARS Catfish (reporter); Dr. Greg Lutz-LSU AgCenter Facilitator: Not available SESSION SUMMARY: Discussed release of USDA 103 broodfish from the Thad Cochran National National Warmwater Aquaculture Center-Marty Fuller gave update:
·	Whether or not fish will be released is to be determined. A data package describing and comparing performance of USDA-103’s with other strain is being assembled. This package will be reviewed in a multistage process beginning with Dr. T. Army (USDA/ARS Mid-South Area Director) and Dr. V. Watson (Director MAFES).
·	If the strain is approved for release, then proposals will be submitted by fingerling producers. The proposal will recommend how the fish get distributed. The proposals will be reviewed by a panel that will determine the distribution strategy.
·	A number of steps are as yet incomplete, the release of the USDA-103’s is not yet confirmed. Who can submit proposals to receive broodfish (what are criteria for being considered a fingerling producer) has not been determined. The committee to review such proposals has not been appointed. Certification procedures for unambiguously identifying the strain have been developed at USDA/ARS in Stoneville. The importance of performance verification for USDA-103’s if/when they’re released was stressed. However, no method for conducting verification trials has been designed. Dr. Morrison described the development of breeder’s associations for other livestock industries, a group of people with an interest in a particular stock. The breeder’s association collects the necessary data and makes the important comparisons to promote the stock.
Terry Tiersch reviewed the work ongoing at LSU in Genetics
·	Use of warm water to extend spawning season by at least 3 months. Channel catfish spawning in February. Mentioned the importance of controlled breeding for genetic improvement.
·	Androgenesis, development of all male homozygous lines. Mostly a research tool for gene mapping, highly inbred individuals. Perhaps some use as YY males.
·	Sperm cryopreservation, the extended time needed for blue males to reach sexual maturity is one case where sperm cryopreservation would obviously help.
Ken Davis reviewed the work at UMemphis
·	Work on sex control XY males and sex reversed XY females are being examined for expression of estrogen receptor and aromatase genes. This is part of an effort to understand why there are no effective hormonal treatments to masculinize channel catfish.
·	Reviewing age and size at maturity in females. Comparing females at multiple ages and sizes to determine if either is the determinant of spawning ability. It appears that age is more important.
·	Ongoing development of YY supermale to enable production of all male stock for aquaculture.
·	Stress response/culture performance-ongoing work to determine if the response to stress is predictive of the fish’s performance (growth, handling, reproductive success).
·	3rd generation gynogenetic individuals. These fish are mainly for research use, highly inbred lines.
Jeff Silverstein reviewed work at USDA/ARS in Stoneville
·	110 full-sib families of USDA-103 fish were produced and some 95 families are being ponded. A number of traits are being measured and will be evalluated for genetic parameters (heritability and genetic/phenotypic correlations) e.g. disease resistance, feed intake and growth, filet yield, reproductive performance.
·	Linkage map of channel catfish, well over 300 markers in 31 linkage groups
·	Strain i.d. using markers (USDA-103 certification)
·	cDNA library subtraction to identify genes important in desirable phenotypes e.g. disease resistant vs. susceptible animals
·	Spawning induction work using slow release LHRH+dopamine antagonist implants

March 24-26, 1997 University of Tennessee Attendees: Chris Dionigi, Hugh Thomforde, Lester Khoo, Meryl Broussard, Bill Wolters, Ken Davis Facilitator: Ken Davis SESSION SUMMARY: Chris Dionigi – USDA/ARS, New Orleans
·	Active interests in genetic selection of channel catfish which do not take up or which quickly depurate off flavors. May be associated with fish with low filet fat content since they have found a positive correlation of MIB concentration in the filet with increased filet fat content. The genetic selection is being done with Bill Wolters at the Catfish Genetics Research Unit.
Bill Wolters- USDA/ARS, CGRU
·	Have had some success with genetic selection of channel catfish strains which show improved growth and disease resistance. Also have identified strains with improved growth and reduced time until maturation.
Kenneth B. Davis, Bill A. Simco, and Cheryl A. Goudie
·	Univ. of Memphis &USDA/ARS, CGRU- Provided an update on the development of YY technology to produce all male channel catfish. Male and female catfish with YY sex genotypes have been identified and spawned with each other. YY catfish have been produced by gynogenesis of XY females. Growth of XY males compared to sibling XY females indicate that the male biased growth is due predominately to phenotype rather than genotype. Dress-out % and mesenteric fat content were somewhat higher in females. However, the advantage in raising all male fish appears to be about 9 to 10 %.
Meryl Broussard- USDA/CSREES
·	Identified two areas of USDA priorities for aquaculture. One is an Aquatic Genetics Steering Committee Co-Chaired by Bill Wolters and Gary Thorgaard, and the second is a National Research Support Project (NRSP) on gene mapping. An Aquaculture Species Genome Mapping Workshop is to be held May 18-19 at the Center for Marine Science and Technology, University of Massachusetts-Dartmouth, North Dartmouth, MA 02747. The workshop has been organized by Dr. Acacia Alcivar-Warren of Tufts University. She may be contacted by e-mail at AALCIVAR@OPAL.TUFTS.EDU

March 24-26, 1996 University of Arkansas, Pine Bluff Attendees: Tim Leard, MSU; Aaron Barkoh, TX Parks and Wildlife; Len Lovshin, Auburn: James Avault, LSU Facilitator: Kenneth B. Davis SESSION SUMMARY: Mississippi State University and Catfish Genetics Research Unit
·	The CGRU has identified some strains which exhibit enhanced growth and those with good disease resistance to ESC. They are presently attempting to correlate physiological characteristics of neutrophils to explain the increased resistance. They are also developing dose response challenges for other diseases. Gynogenetic progeny of XY females were spawned. Males produced by this procedure were expected to have a XY sex genotype. However, only about one-half of the males produce all male progeny.
Texas Parks and Wildlife:
·	Laranne Fries is developing techniques to detect inbreeding in striped bass and smallmouth bass. Gary Garett is working on a hatchery strain of largemouth bass called "Dumb Bass" because of their catchability. Kathy Ramos has developed a technique to take a needle biopsy of liver tissue from live fish. Judy Williams is working on DNA fingerprinting to ID strains.
Texas Tech University:
·	Reynaldo Patino has described the histological development of ovaries in channel catfish. Ovaries can be identified by 19 days after fertilization, however, testes cannot be positively identified until 3.5 months after fertilization. He is also developing techniques to detect and characterize estrogen receptors and expression of the aromatase gene.
Auburn University:
·	Len Lovshin described his success with culturing hybrid channel X blue catfish. These fish have low conversion factors (1.3-1.4), are resistant to ESC, can be processed on the same equipment and have similar dress out percentage as channel catfish. A single seine pass will catch 95% of the hybrid fish in a pond, likely because they are a mid-water fish. These fish must still be produced by hand spawning; however, he reports good success and high predictability of ovulation with injections with carp pituitary. He is holding a demonstration workshop for farmers in Alabama this year.
Louisiana State University:
·	Terry Tiersch is developing techniques for sperm storage. This procedure may be beneficial in supplying blue catfish sperm to fertilize channel catfish eggs to produce hybrid catfish.
University of Memphis and CGRU:
·	Channel catfish - several heterozygotic alleles were identified by protein electrophoresis and Mendelian inheritance was established. Gynogenesis of XY females was used to map these alleles with respect to gene-centromere distances. Identified one gene that is sex-linked (on the same chromosome with the male determining gene). However, this gene is not responsible for influencing the growth advantage apparent with male fish. Identified YY female fish and crossed them with YY male fish. Each of three crosses had very low viability. YY female fish may have an altered hormonal environment during egg maturation.

March 18-20, 1995 Auburn University Attendees: Not available Facilitator: Bill Simco SESSION SUMMARY: Auburn University.
·	Rex Dunham reported his research effort involves a multifaceted approach including selection, hybridization and genetic engineering. Fourth generation of selection of Kansas strain has resulted in a 55% increase in growth over that of controls. The hybrid of Kansas female channel catfish by male blue catfish has resulted in increased growth. Transgenic channel catfish with rtGHc DNA are being evaluated. Research efforts have focused on feed conversion, predation avoidance, spawning ability and foraging ability of transgenic catfish.. Sixteen genetic projects are reported in the Research Summary for this meeting. Chris Austin reported on work related to the genetics of Australian freshwater crayfish, Cherax spp. Ron Phelps reported on research projects related to hatchery management techniques. Relationships of feeding rate, temperature, growth rate spawning success and success of sex reversal are being investigated. Investigations include the mass production of channel catfish x blue catfish hybrid fry.
Fish Farming Experimental Laboratory, USF&WS.
·	Large mixed populations of fish from a variety of sources are being maintained as reference strains for comparisons in selection studies by investigators at various laboratories.
University of Memphis.
·	Females with a YY genotype have been demonstrated to be fertile. Mating with "YY ' males provides the basis for production of large populations of such fish for use as broodfish to produce monosex male populations. Histological studies have been initiated with R. Patino, Texas Tech University, to ascertain the time of sex determination in channel catfish.. Preliminary data indicate female sex is determined earlier than that of males. Sex genotype/phenotype studies indicate that the phenotypic sex is the primary basis for sexually dimorphic growth.
Mississippi State University.
·	A field test of the ability of improved fish strains to reproduce in commercial ponds has shown that they reproduce at the rate of 35%, compared to the rate of 50% for most commercial strains. High energy-low protein feeds were cheaper than low energy-high protein feeds when fed to female broodstock and resulted in similar reproductive performance.
University of Texas at Austin (Marine Science Institute).
·	Controlled environment techniques and closed system technologies are being employed for the maturation and spawning of marine species.
·	North Carolina State University. "Dependable" technology has been developed for programming release rates of GnRHa in implants by varying ratios of cholesterol and cellulose in striped bass, and is being developed for summer flounder/southern flounder.

March 13-15, 1994 Texas A&M University Attendees: Not available Facilitator: Dr. Bill Simco SESSION SUMMARY:
Southeastern Fish Cultural Laboratory (USDI), Marion, AL
·	Reported on research to maximize first-year growth of tilapia in polyculture with channel catfish. Tilapia were sex-reversed (96% males) and stocked at 500, 1000, or 2000/acre with 5000 channel catfish/acre. Approximately 500-1500 lbs/acre of marketable size tilapia were produced, but a similar density of fish not large enough for market resulted from unwanted reproduction. Catfish production was approximately 7000 lbs/acre at all densities of tilapia. The lab also reported on screenings for the inheritance of "triple tail" deformities, environment/hormone interactions in channel catfish, and development of techniques for ploidy determination on newly-hatched fry.
The Catfish Genetics Research Unit (USDA), Stoneville, MS
·	reported on evaluations of distinct stocks of catfish for performance and for genetic expression of temperature tolerance, nitrite tolerance, stress resistance, disease resistance, carcass traits, reproduction, and growth. Strain responses will be correlated with biochemical markers and RFLPs. The genetic basis of disease susceptibility will be investigated by describing blood parameters, by determining immune status of different strains and be selecting and testing disease-resistant fishes. Studies are continuing on genetic and hormonal controls to manipulate sex of catfish to improve catfish production efficiency and product quality. Research will include the creation of gynogenetic and androgenetic lines using biochemically identified strains.
The University of Memphis
·	reported on work on developing male channel catfish with YY genotypes. Fertile males have produced all-male offspring when mated with normal XX females. Efforts are continuing to identify females with the altered YY genotype. Research at UM is continuing to develop methods for the identification of the sex genotype in catfish. GPI-b has been demonstrated to be sex-linked in catfish and to have a recombination frequency with the SDG of approximately 15%. A project in cooperation with Texas Tech University will address the period of sex determination in channel catfish.

No other laboratories provided information related to research on genetics and reproductive physiology.

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March 9-11, 2003 Texas A&M University Attendees: Not available Facilitator: Not available SESSION SUMMARY:
·	Ken Davis announced SNARC would have two geneticist positions open soon. He also briefly mentioned the national genetics project in development for the striped bass industry.
·	Del Gatlin discussed current genetics projects at TAMU involving hybrid striped bass and red drum in which microsatellite markers are being developed for stock identification and assessment of heritability of selected production traits.
·	Gary Burtle mentioned the hybrid catfish work that is in progress at Georgia, Auburn and the ARS Catfish Genetics Lab.