Animal Sciences Commons^™

Genome-Wide Analysis Of Acute Low Salinity Tolerance In The Eastern Oyster Crassostrea Virginica And Potential Of Genomic Selection For Trait Improvement, Alexandra J. Mccarty, Standish K. Allen Jr., Louis V. Plough

VIMS Articles

As the global demand for seafood increases, research into the genetic basis of traits that can increase aquaculture production is critical. The eastern oyster (Crassostrea virginica) is an important aquaculture species along the Atlantic and Gulf Coasts of the United States, but increases in heavy rainfall events expose oysters to acute low salinity conditions, which negatively impact production. Low salinity survival is known to be a moderately heritable trait, but the genetic architecture underlying this trait is still poorly understood. In this study, we used ddRAD sequencing to generate genome-wide single-nucleotide polymorphism (SNP) data for four F_{2 …}

Environmentally-Determined Production Frontiers And Lease Utilization In Virginia's Eastern Oyster Aquaculture Industry, Jennifer Beckensteiner, Andrew M. Scheld, Pierre St-Laurent, Marjorie A.M. Friedrichs, David M. Kaplan

VIMS Articles

During the last decade, oyster aquaculture has rebounded in Virginia and has been associated with an increase in subaqueous leased area. Production levels remain historically low, however, and many leases are thought to be underutilized. This study uses a novel approach leveraging high-resolution environmental data to evaluate lease utilization and identify constraints on aquaculture development. Stochastic Frontier Analysis (SFA) and Data Envelopment Analysis (DEA) were used to define environmentally-determined production frontiers, i.e. production possibilities based on empirical observations of aquaculture production, available space, and environmental conditions. Both methods estimated Lease Capacity Utilization (LCU, from 0 to 1) for leases producing …

Barriers To Eastern Oyster Aquaculture Expansion In Virginia, Jennifer Beckensteiner, David M. Kaplan, Andrew M. Scheld

VIMS Articles

The eastern oyster once provided major societal and ecosystem benefits, but these benefits have been threatened in recent decades by large declines in oyster harvests. In many areas, recovery of oyster aquaculture faces significant societal opposition and spatial constraints limiting its ability to meet expectations regarding future food needs and provision of ecosystem services. In Virginia, oyster aquaculture has begun to expand, concurrent with an increase in subaqueous leased areas (over 130,000 acres of grounds are currently leased). Though private leases must in theory be used for oyster production, in practice, they can be held for other reasons, such as …

A Data Repository For Minimal Effects Of Oyster Aquaculture On Water Quality: Examples From Southern Chesapeake Bay, Jessica Turner, Grace M. Massey, M. Lisa Kellogg, Carl Friedrichs

Data

The objective of this study was to quantify the effects of oyster aquaculture on water quality, sediment quality, and hydrodynamics at select sites in southern Chesapeake Bay. To this end, information was gathered over the course of approximately one year from February 2017 to October 2017 at four operating commercial farms. Farms were sampled during spring, summer, and fall seasons during times of oyster filtration activity when temperatures were greater than 10^oC. Aquaculture sites differed in environmental setting, in terms of their exposure to waves and resulting sediment characteristics. Sites had mesohaline salinities (ranging from 15-22 psu) and …

Direct Setting Of Eyed Larvae: In Situ Spat-On-Shell, Andrew Myles Cockrell

Reports

Experiments were conducted in hopes of developing techniques whereby an individual, with a minimum of equipment and labor, can utilize eyed larvae to profitably induce strike on appropriate oyster leases. The best-case scenario would be to utilize shell already present on the lease. Adding clean shell produced better results.

Feasibility Of A Recirculating Aquaculture System For Early Larval Culture Of Crassostrea Virginica, Michael Congrove

Reports

Oyster aquaculture in Virginia is a rapidly developing industry with greater than 75 million oysters planted in 2010, this compared to just 6 million in 2005 (Murray and Hudson 2011). Necessary to support this rapid development, among other things, is a large and consistent supply of larval and seed oysters, from which oyster growers start their crops. Providing this product to the aquaculture industry are hatcheries.

Hatcheries represent the tip of the pyramid in oyster aquaculture. Only a few hatcheries with a handful of workers support a much larger industry of many growout operations collectively employing hundreds of workers. Hatcheries …

Early Spat On Shell Setting, Rufus H. Ruark

Reports

Setting for spat on shell typically beings when water temperatures reach about 20° C. This optimal temperature is normally reached in Virginia's climate by May. Setting spat on shell is completed by September; this gives the spat just enough time to grow before the cold of winter puts them in hibernation. Hatcheries start spawning oysters as early as February. By heating the water and adding food they can successfully produce millions of larvae during the cold winter months. When the ambient water temperature rises it brings more food but in many cases poor water conditions. Unfortunately, in the heat of …

Stake In The Bay, Michael J. Gadwell

Reports

The Stake in the bay project was instituted to make it possible for people of all ages and agility to become involved in the oyster replenishment and restoration. This was accomplished by my wife and I utilizing over a dozen different recipes and types of stakes and slurri.es to encourage spat attachment using triploid larvae set in our onshore setting tank which is also utilized for setting spat on shell.

Feasibility Of Converting Crab Shedding Tanks To Effectively Set Single Oyster Seed For Aquaculture And Comparison Of Technique To Traditional Remote Setting Practices: Final Report, Bevans Oyster Company, Cowart Seafood Corporation

Reports

The goal of this project was to design and implement a simple, single oyster setting system. More intricate single seed setting systems are typically employed at commercial shellfish hatcheries. However, this project aimed to demonstrate a simplified single seed setting system using existing crab shedding systems making it possible for a wider spectrum of the seafood industry.

An Investigation Into The Beneficial Effects Of Intentionally Exposing Oysters To Air During Their Normal Growing Season, Dennis K. Gryder, Michael Oesterling, Richard H. Couch

Reports

This report describes a field experiment which was primarily intended to quantify the beneficial effects of intentionally exposing oysters to air during their growing period. Test samples were submerged in the water at different depths and the normal tidal activity uncovered the samples for differing percentages of the tide cycle. The amount of time each sample was in air was monitored by a specially designed electronic instrument and logged. The logged data was processed into graphical data showing the growth rate of the test subjects with respect to exposure. The occurrence of Polydora was also monitored during periodic inspections and …

Re-Examination Of The Feasibility Study On One-Year Grow-Out Of Triploid Crassostrea Ariakensis 2007-2008, Virginia Seafood Council

Reports

The Virginia Seafood Council has been involved in the study of Crassostrea ariakensis as a potential non-native product for the Chesapeake Bay since its inception in 2000. Since then, the Council has helped to organize and carry out several experiments using these oysters. Starting out with just a few thousand oysters per project, now in its 8th year working with this oyster the Virginia Seafood Council has completed another project with 700,000 oysters.

Virginia Oyster Aquaculture Production And Marketing Virginia Oyster Aquaculture Production And Marketing Survey, Paul Jesperson, Shawn Stickler

Reports

As aquaculture replaces wild harvest of oysters in the Chesapeake Bay region, we felt that there was a need to reevaluate how producers could get their products to market in the most efiicient, profitable way. In order to do this, we wanted to capture the lessons learned in other regions that have already made the progression from wild harvest to aquaculture, such as France, New England, and the Pacific Northwest.

In this study, we examined the methods of productions and marketing that are currently in use in regions beyond the Chesapeake, including the Northeastern United States, the Pacific Northwest, and …

Project Management For Virginia Seafood Council’S Economic Analysis Of Triploid C. Ariakensis Aquaculture (Year 1 And 2), A. J. Erskine

Reports

The Virginia Seafood Council (VSC) project for 2003-2005 focused on industry field trials with genetic triploid Crassoslrea ariakensis. This entailed deployment of approximately 100,000 C. ariakensis at each often industry participants' private oyster grounds to test aquaculture grow-out methods and marketability. In addition deployment of genetic triploid C. virginica allowed for a side-by-side comparison.

Grow-Out And Marketability Evaluation Of Triploid Deby Oysters, Gustavo Calvo

Reports

Triploid DEBY clearly outperformed their diploid counterparts in terms of survival, growth and condition over the course of this study at the site of Sweet Amalia Oyster Farm in Mathews, VA. By November 2004, when oysters were approximately 28 month old, cumulative mortality was 11 % in triploids and 43% in diploids. At that time, 41 % of the triploids were of market size (3 inch) whereas none of the diploids had even attained 2.5 inch. Condition of triploids and diploids similarly increased in fall 2003 and remained high over the winter and spring 2004. However, while condition decreased slightly …

Development Of Grow Out Techniques Utilizing The Water Column In Growing A Non Native Oyster (Crassostrea Arikensis), Andy Drewer

Reports

This project addressed grow out techniques utilizing the water column in growing non native oysters (Crassostrea arikensis) in a containerized manner. The purpose of this project was to evaluate the cost effectiveness of growing, in commercial quantities for the processing segment of the industry, a non- native oyster in different types of stackable trays suspended in the upper water column by a raft.

Testing A New Approach For Floating Cultivation Of Oysters On The Seaside, Jeffrey Hammer

Reports

The purpose of this project was to evaluate the use of a floating bag method of oyster cultivation on the Seaside of Va. The use of a disease resistant seed stock. The use of a strict protocol, which involved aggressive culling and, removal of slower growing animals early on in the grow-out phase.

Growing Oysters In Suspended Bags Using Ropes, Anchors And Buoys, Curtis B. Jenkins

Reports

The purpose of this project was to see if it is feasible to grow oysters suspended off the river bottom in bags by using ropes, anchors and buoys. Growing oysters in this manner would allow oysters to be grown on oyster ground with bottom not suitable to grow oysters.

Comparative Study Of Four Popular Grow Out Methods, Jack White

Reports

The 'Comparative Study of Four Popular Grow Out Methods' was undertaken to examine four promising grow-out methodologies for a small aquaculture operation and to compare them with regard to costs, convenience, maintenance and performance. Its objective was to determine whether any system emerged as more cost effective and efficient than the others, and whether a clear choice exists. Stated more simply, it was an opportunity to explore the "pros and cons" of the various systems in use.

Validation Of An Individual Quick Freezing (Iqf) Process To Reduce Vibrio Vulnificus Numbers To <30mpn/G In Raw Oysters, Ron Bevans, Luke Cowart

Reports

This validation study was conducted during the months of July, August and Sept., 2003. The Food and Drug Administration and the Interstate Shellfish Sanitation Conference require that oysters used for a validation study are collected during the same processing day, are from the same lot of shellfish, and have an adjusted geometric mean (AGM) MPN of at least I 00,000/g of Vibrio vulnificus as an initial load. The oysters were removed from refrigerated storage and held at 71 °F (21 °C) for 40-45 hours prior to freezing in order to achieve a minimum AGM of 100,000/g Vibrio vulnificus . After …

Control Of Mud Blister Formation In Oysters, Dennis K. Gryder

Reports

Oyster aquaculture, both commercial and recreational, continues to elicit interest, despite ongoing disease problems. One strategy for growing oysters in the presence of oyster diseases is to utilize off-bottom technology in order to "out-grow" the pathogens. It's acknowledged that oysters grown off-bottom grow quickly, but tend to have thinner, more brittle shells than those grown on-bottom. Due to the increased expenses of equipment and handling associated with growing oysters off-bottom, most oysters grown commercial in this manner are destined for the more lucrative half-shell market. In order to command higher prices, besides having a good flavor, half-shell oysters need to …

Comparative Study Of Seed From Northern And Southern Hatcheries, Joshua Merritt, Paige G. Ross

Reports

Seed from Northern and Southern (hereafter called local) hatcheries was procured in May 2000. Oysters delivered by the Northern hatchery were on time and of the desired size ~3mm). Seed from the local hatchery, however, arrived several days later and were too small to go into field nursery containers and were subsequently held in upwellers and then transferred to the field nursery gear. Figure 1 shows growth as measured by mean shell height (mm) for both strains. Note that the local seed took N20 days longer to reach grow-out size (indicated by first sieve).

Artificial Reef Grow-Out, Jeff Hammer

Reports

The purpose of this project, was to address the possibility of improving upon the cun-ent grow out procedures currently being used by the oyster aquaculture industty. I.e. Taylor floats - Rack and bag.

As stated in the proposal, the current adopted method of raising oysters is to use Taylor floats. This method has proven to be effective in producing market sized oysters in 1- 2 years, although intensive labor cost and high fouling rates decrease profit margins considerably. Also the availability of suitable sites is now under increased regulations and is not welcomed in some waterfront communities.

My proposal was …

Enhancement Of Seed Oyster Recovery And Redeployment: Final Report, William Magann

Reports

Today's task involved loading harvesting bag with 1,220 lbs of ballast stone and hanging in test frame. This test will test support straps for fraying or unraveling and test overall for bag durability.

Comparative Growth Rates Of Four Strains Of The American Oyster Using Two Grow-Out Methods, Thomas Leggett

Reports

4 strains of the American oyster were grown using two grow-out methods; rack and bag as is done in France, and bottom trays stacked on PVC racks. Growth was measured over a 10-monthperiod and the suitability of each grow-out method was qualitatively evaluated for suitability for use in oyster aquaculture in the Chesapeake Bay. There appeared to be little difference in growth rate between strains, however growth appeared more rapid using the rack and bag method for all strains. In addition, the rack and tray method was slightly more expensive fur more labor intensive and difficult to manage than the …