aquaculture trade

Selective Breeding of Penaeus vannamei for Whitespot Resistance in China

2011-02-14T22:26:00.000-08:00

Abstract: After three generations of selective breeding for whitespot virus resistance, 29 families of Penaeus vannamei were divided into three groups: high, moderate and low resistance. After infection with whitespot, the average survivals for the groups were 22.7, 9.08 and 0.78 percent, respectively. The peak in mortality in the high-resistance group occurred two to three days after the peaks in the low-resistance group and controls.

Source: Aquaculture. Characterization of WSSV Resistance in Selected Families of Litopenaeus vannamei. Yong-Chun Huang, Zhi-Xin Yin, Hua-Shu Ai, Xian-De Huang, Se-Dong Li, Shao-Ping Weng and Jian-Guo He (lsshjg@mail.sysu.edu.cn, State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275, PR China). Volume 311, Issues 1-4, Pages 54–60, February

Chamberlain Talks GAA, BAP In Asia, Chile

2010-11-26T00:53:00.000-08:00

Chamberlain Talks GAA, BAP In Asia, Chile

Global Aquaculture Alliance President George Chamberlain represented GAA and the Best Aquaculture Practices (BAP) certification program at varied international venues in recent months.

China
Chamberlain presented a talk on “The Role of Industry Associations in Adding Value” at the annual conference of the International Fishmeal and Fish Oil Organisation (IFFO) in Beijing, China, on October 26. He explained GAA’s evolution, including the implementation of its BAP standards, and recommended continued collaboration between GAA and IFFO in their respective certification programs and annual meetings. IFFO is an international non-profit organization that represents fishmeal and fish oil producers and related trades throughout the world. IFFO has developed a global certification program for the responsible supply of fishmeal and fish oil that, like BAP, recognizes the importance of responsible sourcing, production and supply practices. GAA and IFFO are now working toward interconnecting BAP certification and the IFFO responsible supply standards to demonstrate the sustainability of the complete aquaculture supply chain. Indonesia In early October, Chamberlain presented “Global Status of Shrimp Farming” at the Indonesian Aquaculture meeting in Lampung, Indonesia. With a special emphasis on certification, he discussed the importance of sustainability as technology advances in breeding and intensive culture. Chamberlain also addressed disease issues, including the infectious myonecrosis virus that is plaguing Indonesian shrimp farms.
The Ministry of Marine Affairs and Fisheries holds Indoaqua to share new technology with varied stakeholders and highlight innovations in the aquaculture sector.

Thailand
Chamberlain met with representatives of the Thai Board of Trade and Thai Frozen Food Association September 20 to discuss benchmarking of standards and traceability data. To gain additional credibility in world markets, Thailand established the ThaiGAP program of quality management for farmed products, which certifies food safety. The ThaiGAP standards have been benchmarked to the international Global-GAP system, and there is interest in benchmarking ThaiGAP with the Best Aquaculture Practices certification program for farmed seafood. The meeting was an opportunity for GAA to further collaborate with the newly formed ThaiGAP. Thai shrimp farmers are already recording some traceability data that could be made
compatible with BAP’s required traceability system.

Chile
In Puerto Montt, Chile, Chamberlain made two presentations on certification –
“Trends and Benchmarking” and “Customer and Retailer Views” – in a September 9 meeting
of approximately 70 industry participants called ABCs of Certification. Organized by Adolfo
Avial Associates, the event included presentations about the Best Aquaculture Practices program, GlobalGAP, SalmonChile and the World Wildlife Fund’s salmon standards. On September 10, BAP auditor Giovanni Garofalo visited two major processing plants to conduct
a preassessment audit of compliance with BAP standards.
His analysis indicated that Chilean salmon-processing plants are well positioned to become BAP-certified.

Shrimpculture in The Rainy Season

2010-11-16T21:45:00.000-08:00

The Rainy Season, Do not be Lazy to Feed for Shrimps
During the rainy season, the feeding programs (mainly related to the daily feeding) is usually disrupted both the feeding frequency and the level of prevalence of feed distribution in the pond. This condition is more influenced by human resource factor, mainly who is responsible for providing feed on shrimps. The factor associated with this condition is the level of discipline in conducting the feeding program that has been determined. It can not be denied, during the rainy season usually creates a feeling lazy on human.

As already mentioned above that aspects of feeding programs are usually disrupted during the rainy season is the levels of feeding frequency and feed distribution prevalence. If connected with a sense of lazy that appears during the rainy season, the feeding conditions that occur are as follows:

1. During the rain, feeding program is not conducted. This condition cause a reduction in feeding frequency on that day;

2. During the rain, the feed given to shrimp is not scattered evenly in the pond but just piled on some point locations. This condition causes the feed is not spread evenly.

Both conditions mentioned above, if conducted repeatedly in one period may lead to disruption of shrimp condition especially on the level of shrimps uniformity even in extreme conditions can cause a decreasing in shrimp populations with the rationale as follows:

1. Feed given unevenly in a pond (only in some locations) lead to some shrimps in a population missed the feed to be consumed. This condition can cause the level of shrimp growth in the population is not the same relatively, so if this happens repeatedly, the level of shrimps uniformity in the population will vary;

2. Reduced frequency of on shrimp feeding at a a moment will be able to make the shrimp in the process of cannibalism as a “claim” against the needs of feed at that time. Continuous process of cannibalism which will cause the decreasing of shrimp population in a cultivation period.

Referring to the mentioned explanation above, even though the rainy season it should avoid feeling lazy in providing feed to the shrimp. Discipline factor is one important factor in the shrimp culture, especially during the rainy season. However as is often described in previous discussions that one of the basic philosophy of shrimp culture is "we follow the shrimp needs not the shrimps follow our desire." Referring to this condition it can be said that the shrimps were also always having needs that must be met in any season. So when the rainy season, it should avoid the feeling lazy to feed on shrimp, because when rain the shrimps also require feed to be consumed.

Global Outlook for Aquaculture Leadership

2010-11-13T01:12:00.000-08:00

GOAL 2010 Highlights Shifting Seafood Demand,
Need for Greater Aquaculture Productivity
Economist Albert Zeufack set the stage for a GOAL 2010
that revealed strategic global trends driving seafood demand and
increased aquaculture productivity by describing in his keynote
how global economic power is shifting from West to East.
The shift is creating a large new middle class in the Asian economies,
particularly in China, Zeufack said at the October 17-20
meeting in Kuala Lumpur, Malaysia. This in turn is driving a surge
in seafood consumption that far outstrips previous projections based
solely on population increases. This megatrend is already well under
way and is expected to continue for several decades.
The nearly 300 international aquaculture and seafood industry
leaders at Global Outlook for Aquaculture Leadership
(GOAL) 2010 also heard that imported seafood is playing agrowing role
in the domestic market of China, by far the world’s
leading aquaculture producer.
Economist Ragnar Tveteras evaluated economic indicators
from the International Monetary Fund and World Bank and
stated that China will shift from being a net seafood exporter to
a net seafood importer by 2011. His conclusion triangulated
with feedback from other speakers on the Chinese market.
Organized by the Global Aquaculture Alliance, the GOAL
meeting was co-hosted by the Malaysia Department of Fisheries
at the Shangri-La Hotel in Kuala Lumpur. GOAL 2010’s
momentous conclusions helped buyers and producers adjust their
strategic plans to avoid potential disruptions in supply and
demand.
With the framework of surging seafood demand in mind,
GOAL speakers addressed the question of how to sustainably
increase production. One recommended thrust was to utilize
improved technology. Robins McIntosh of the C.P. Group the
described advances in penaeid shrimp technology using genetically
improved animals within controlled growout systems to increase
productivity. Shorter cycles also drive down feed and energy costs.
This solution produces more seafood with fewer resources.
Another recommendation was expansion of production area
into undeveloped regions, particularly Africa, where such economic
development would lead to important community benefits.
In order to assure sustainability, GOAL speakers also
emphasized the importance of certification and traceability of
each link in the supply chain. Updates were provided on GAA’s
newly released Best Aquaculture Practices standards for
Pangasius and feed mills, and the status of salmon standards,
which are expected soon. Participants at GOAL 2010 provided
feedback on major issues through individual responses to questions
posed through an audience response system.
A key benefit of GOAL was the opportunity for industry
leaders to network during pre-conference tours, luncheons, coffee
breaks and receptions. A highlight of the event was the gala
reception at the prestigious Malaysian Petroleum Club, which
offered a commanding view of Kuala Lumpur from the heights
of the city’s trademark Petronas Twin Towers.
GOAL 2010 helped identify a pivotal point for global aquaculture
production. The Global Aquaculture Alliance plans to
follow up on the trends it examined in Malaysia at GOAL 2011,
scheduled for Santiago, Chile, in late October or early November of next year.

BAP Standards Oversight Committee Approves Feed Standards

2010-11-13T00:46:00.000-08:00

BAP Standards Oversight Committee Approves Feed Standards,
Considers IOMs For Small Farms
Continued progress in standards development and market
reach was reported at the Best Aquaculture Practices (BAP)
Standards Oversight Committee (SOC) meeting held March 14
in Boston, Massachusetts, USA.
In his introduction, GAA Executive Director Stevens summarized
the overall progress of the BAP program. He referred to
large posters and said market demand for “two-star” product
from BAP-certified farms and processing plants is driving an
increase in farm certification, particularly at tilapia facilities.
Additional processors are becoming engaged in anticipation of
the BAP salmon farm standards.
Stevens also described the proposed new organizational
structure that would integrate the Aquaculture Certification
Council (ACC) with GAA to manage the BAP certification
process using ISO-accredited inspection bodies to conduct facility
audits. Under the plan, the SOC would become part of the
Responsible Aquaculture Foundation, a new body with charitable
status. Within the foundation, Jeffrey Peterson would direct
BAP’s education and training program.

Integrated Operating Modules
ACC President Jim Heerin joined Vice President Bill More
and Peterson in providing an update on the Integrated Operating
Module (IOM) program for multiple small shrimp farms.
In IOMs, a number of farms with similar production methods
and combined total annual production not exceeding 4,000
mt can be grouped together. All undergo full inspections and
participate in traceability, but modified administrative arrangements
allow the farms to save on certification costs. Each IOM
must have a written quality management system defining how
the group is managed to meet BAP standards criteria.

Feed Standards
The BAP feed mill standards were approved for release
pending final changes and review. Requested changes included a
requirement that sources for all fishmeal and fish oil be certified
to the International Fishmeal and Fish Oil Organisation (IFFO)
Global Standard for Responsible Supply or Marine Stewardship
Council program within three years. Until that time, feed mills
are required to develop a plan for transition to sustainable fishmeal
sources.

Tilapia, Salmon Standards
Review of the BAP standards for tilapia farms saw a request
to begin collecting fuel and energy use data so figures for direct
energy use can be calculated. The SOC recommended the establishment
of a minimum mean annual survival rate as an indicator
of fish welfare. It was also suggested that the guidelines for predator
control should be further strengthened and defined.
Progress continues to be made on the BAP standards for
salmon farms. Jon Bryan of the Tasmanian Conservation Trust
was approved to join the Salmon Farm Technical Committee.
As at tilapia facilities, fuel and energy use data will be recorded.
In the future, such topics as greenhouse gases, acidification,
biotic resource utilization, accumulated energy and eutrophication
potential may be addressed in the standards.

Introduced Species
The BAP standards require documented proof that it is legal
to farm a species in a particular place. To strengthen this, the
applicability of the International Council for the Exploration of
the Sea (ICES) Code of Practice on the Introductions and
Transfers of Marine Organisms 2005 was considered.
The code outlines requirements for member countries to
consider ecological, genetic, disease and economic impacts prior
to introducing a marine species. However, ICES only has 20
member countries, with no tropical or developing countries. It
was concluded that the BAP program is functionally equivalent
to the World Wildlife Fund tilapia standards regarding introduced
species.

Social Accountability
Various options were discussed as to how to strengthen social
accountability in the BAP standards. They could include a specific
anti-discrimination clause and bans on forced or bonded
labor. Interviews with workers could be conducted off site to
allow more freedom in responses.
Collaboration between BAP and Fair Trade certification –
which channels price premiums back to producers for social
projects and community benefits – may be considered. In a presentation,
Maya Spaull of TransFair explained that Fair Trade
certification does not aim to duplicate BAP. The program
addresses economic and social criteria in the production and
trade of agricultural products, and wants to address environmental
issues, but not through its own standards.

Audit Formatting
BAP’s shift to ISO-65-accredited certification bodies for
inspections saw a corresponding shift in the audit documents.
BAP’s original audit forms included critical and scored questions,
while the new processing plant audit has eliminated all
scored questions in favor of the yes/no responses typical of
GFSI-compliant standards.
To make the program more consistent across facility types,
possible solutions include converting scored questions “up” to
critical or “down” to recommendations in the guidelines.
Another option is to keep the scoring system, but identify persistent
problem areas and then modify the standards accordingly.
No decision on how to address the situation was made.

Perch (barramundi) in pond

2010-10-19T18:05:00.001-07:00

Black Tiger Shrimp

2010-10-17T23:11:00.000-07:00

Black Tiger Shrimps are commonly found in Southeast Asia. These shrimp are shipped raw shell-on, EZ Peel, PTO, cooked and other value added presentations.

Black Tiger Shrimp are a highly adaptable seafood for the kitchen, suitable for all cooking methods.

Most Black Tiger Shrimp available in the United States are raw, shell-on, EZ Peel and CPTO. Most Asian consumers prefer raw Head On.

Black Tiger Shrimp have brown, blue, gray and black striped shells which cook to a pink, orange and red color.

Occasionally you may find shrimp that have paper-thin or soft shells. These are simply shrimp that molted shortly before being harvested; they are of the same quality as others with more solid shells. All shrimp are in a continuous cycle of molting as they grow, exchanging their snug, smaller shell for a new thin shell that hardens until the next molt. Black tiger shrimp grow especially quickly, because they are grown in warm, tropical waters, so they molt quite often.

The shrimp are sometimes sold in the retail sector with classifications of medium or large, while industry sizing is based on a per-pound value. For a shrimp labeled 21/25, there will be between 21 and 25 shrimp in one pound. The smaller the number, the larger the shrimp.

Black tiger shrimp are the single most widely distributed and marketed shrimp in the world. Harvests occur along coastlines in a eastward arc from the southern tip of Africa almost to the Sea of Japan. About 80 percent of the black tigers on the market are farmed, with the remainder coming from various Asian countries. These shrimp are easy to farm, because they are quite adaptable and thrive in a wide range of environments.

Black tiger shrimp are widely available year-round, although the supply of farmed shrimp peaks in February and September and prices should be somewhat lower then. Generally, the larger the shrimp, the higher the price.

New Fish Feeds Made From Fish By Products

2010-10-07T17:40:00.000-07:00

US - Fish by-products may be a new source of fish feed, thanks to research by US Department of Agriculture (USDA)-funded scientists in Hawaii.

Research scientist Dong-Fang Deng and her colleagues with the Oceanic Institute in Waimanalo, Hawaii, are collaborating with USDA food technologist Peter Bechtel to develop the new fish feeds. Dr Bechtel is with the USDA Agricultural Research Service (ARS) Subarctic Agricultural Research Unit in Kodiak, Alaska. ARS is the USDA's principal intramural scientific research agency.

The scientists are taking fish parts that would normally be discarded—head, tail, bone, skin and internal organs – and fashioning them into feeds for shrimp and fish. They are currently testing the feeds on Pacific threadfin (Polydactylus sexfilis) – or 'moi' as Hawaiians call it – and Pacific white shrimp (Litopenaeus vannamei).

The researchers then characterise the nutrient composition of the feeds, evaluate their ability to attract the shrimp and moi, estimate the food's digestibility and assess the growth of the animals. Recent tests have shown that many of the Alaska fish parts work well as feeding stimulants, which entice the shrimp to eat the plant-protein-based feed to which fish byproducts had been added.

In an earlier ARS-funded study with moi, former Oceanic Institute scientist, Ian Forster, found that the nutritional quality of feeds made with discarded portions of Alaskan pollock and cod was equivalent to that of feed made from Norwegian fishmeal, generally regarded as the highest standard in the aquaculture feed industry. Forster and his colleagues found the same result when feeds were tested on shrimp.

According to Dr Deng, the scientists are currently examining how to best use fish by-products to develop practical feeds that are nutritionally balanced, cost effective and safe for the environment.

Details about these feed studies have been published in the Journal of the World Aquaculture Society and the Journal of Aquatic Food Product Technology.

Global Experts Study Aquatic Animal Disease

2010-10-05T04:48:00.000-07:00

CANADA - The Atlantic Veterinary College (AVC) at the University of Prince Edward Island and the National Veterinary Institute in Norway have joined forces to establish the world’s only OIE Collaborating Centre for Epidemiology and Risk Assessment of Aquatic Animal Diseases.

The World Organisation for Animal Health (OIE) confirmed the designation of the Centre during its annual general session in Paris in May 2010. OIE Collaborating Centres play a key role in the management of animal health issues and resulting impacts on the health of communities around the world. The OIE Collaborating Centre designation recognizes world leadership in aquatic epidemiological research for aquatic food production based at AVC and the National Veterinary Institute (Norway).

“Aquaculture is the fastest growing food sector in the world,” says Dr Larry Hammell, Co-director of the OIE Collaborating Centre, Director of AVC’s Centre for Aquatic Health Sciences and Innovation PEI Industry Research Chair in Epidemiology for Aquatic Food Production.

“Increasingly, countries around the world are turning to aquatic species as a source of high quality food for their populations,” explains Hammell. “This requires healthy food animals from healthy aquatic ecosystems. Establishing this Collaborating Centre is a timely and necessary step in supporting the future of aquatic health management on a global scale.”

“This partnership between our two institutions is a very exciting opportunity to solidify even stronger linkages, and develop research and training programs for other aquatic food producing countries,” says Dr. Edgar Brun, Head of the Epidemiology Section, National Veterinary Institute (Norway) and Co-director of the OIE Collaborating Centre.

Researchers from a range of aquatic health-related disciplines including finfish, mollusc and crustacean field studies will be part of the Centre. The Centre will focus on evidence-based health management using epidemiology--the study of disease in populations--for aquatic health issues.

It will also provide training for producers and scientists, conduct research involving local veterinarians and producers, and deliver services to the aquaculture industry and governments in areas such as:
. disease outbreak investigations and risk factor studies,
. surveillance and diagnostic test evaluation,
. disease control and clinical field trials,
. decision-support tools that deliver evidence-based outcomes to all levels of policy makers,
. training of experts in aquatic epidemiology and evidence-based health management,
. epidemiological risk assessment.

“Ensuring a safe, sustainable and affordable supply of food is an ongoing issue for much of the world’s growing population,” says Dr Brian Evans, Canada’s Chief Veterinary Officer and the country’s first Chief Food Safety Officer.

“The establishment of the OIE Collaborating Centre for Epidemiology and Risk Assessment of Aquatic Animal Diseases is an important contribution to both food security and to the global economy. Given the standards and competence that must be demonstrated to achieve designation by the OIE, it speaks volumes of the expertise and scientific excellence resident at AVC and at Norway’s National Veterinary Institute.”

The establishment of this OIE Collaborating Centre formalizes a network of global experts and will greatly increase knowledge and capacity needed to solve health management issues involving aquatic species. In addition to improving the health of aquatic species, the Centre will provide the scientific basis to influence international standards and guide policy decisions at all levels, including groups such as fish farmers, veterinarians, subnational and federal governments.

The Atlantic Veterinary College and the National Veterinary Institute (Norway) are world-leading academic-based aquatic health institutions. In addition to the OIE Collaborating Centre for Epidemiology and Risk Assessment of Aquatic Animal Diseases, AVC is home to an OIE Reference Laboratory for Infectious Salmon Anaemia (ISA), a Canada Excellence Research Chair in Aquatic Epidemiology, an Aquatic Diagnostics Laboratory, and several centres of aquatic species expertise.

Study Highlights Critical Contribution Of Hatchery Fish

2010-10-02T21:37:00.000-07:00

US - The Prince William Sound Aquaculture Corporation [PWSAC] has released findings from an economic study that confirms a long-held suspicion: hatchery fish are critical to the sustainability and health of Alaska's commercial salmon fishery, the sport fishery and to regional and statewide economies.

Cordova-based PWSAC operates five hatcheries in the Prince William Sound/Copper River region, all of which generate millions of pink, chum, Coho and sockeye salmon for the common property commercial fleet, sport fishery, subsistence and personal use fishermen. In fact, the 2010 season produced the largest run of pink salmon in the history of the fishery, said Dave Reggiani, PWSAC general manager, and the huge return has added to the importance of PWSAC's presence and economic impact around the state.

The new snapshot, done for PWSAC by the McDowell Group of Anchorage and Juneau, examines the impact of those hatchery-produced fish, and found that in 2010, PWSAC salmon accounted for:
. 30 per cent of the statewide salmon harvest
. $317 million in total economic output
. 2,750 jobs
. $67 million in labor income for more than 30 regional economies, and,
. $1.8 million in fisheries business tax revenues to the state and nearly another $1 million in revenue to other local government treasuries.

"One of the things that has made this program so successful and sustainable from a financial point of view is that the fish pay for themselves," Mr Reggiani said. "We sell a portion of the fish returning to the hatchery and that helps pay for the next generation. Our hatcheries also are critical to the sustainability of jobs, strong local economies and the continued growth and investment by processors. They are a tremendous resource and a huge economic engine."

Cordova Mayor Jim Kallander agrees. "PWSAC is driving the economy of the entire North Gulf region," he said, "and aquaculture is vital to their future. The millions of pounds we ship out of here in finished and raw product, through other regional communities and through Anchorage do support jobs... we provide a lot of jobs, we put a lot of kids through college throughout Alaska and throughout the world who come here to work."

Markets for Alaska seafood and value-added salmon products enhance the demand for hatchery fish, Mr Reggiani said, and that makes a reliable return even more critical.

Clay Koplin, CEO of the Cordova Electric Cooperative, remembers when there were empty storefronts on main street: "There isn't a vacant storefront these days... It's jobs, jobs, jobs. It's the economy. The more sustainable the fisheries, the more reliable the fisheries, the more reliable the volume, it will continue to grow, and people can have confidence that the economy is going to be sustainable."

According to the McDowell study, in 2010 hatchery-born fish accounted for:

. 188 million pounds of PWSAC pink salmon harvested by the commercial fleet;
. $51 million PWSAC salmon harvested by the common property fisheries;
. $196 million in the ex vessel value of PWSAC salmon [price paid to fishermen];
. The first wholesale value of salmon [value of fish after it is sold out of the processing network] is not yet available. However, the record ex vessel value of the 2010 harvest suggests that processors will see those values rise well above those in 2008 when processors sold PWSAC salmon for $193 million.

Fish Consumption Patterns

2010-09-24T18:43:00.000-07:00

The next section of an FAO report looking at the impact of rising feed ingredient prices on aquafeeds and aquaculture production, looks at fish consumption patterns in Asia and Europe and the implications for the use of feed in aquaculture. Written by Krishen Rana, University of Stirling, UK and Mohammad Hasan, Fisheries and Aquaculture Management Division, FAO.

During the 1990s, global apparent consumption of fish increased. The global average apparent per capita consumption increased from about 9 kg per year in the early 1960s to 16.3 kg in 1999 (WHO, 2002). The global per capita availability of fish and fishery products has, therefore, nearly doubled in 40 years, outpacing population growth. This development was heavily dominated by events in China, which emerged as the world’s largest fish producer during this period (Popkin, 2001). In fact, excluding China, the apparent consumption per person in the rest of the world actually declined from 14.4 kg in 1990 to 13.1 kg in 1999. However, it is important to note that such global figures mask the very wide differences among countries in the amount of fish used for food consumption (FAO, 2003) (Table 15).

In both Asia and Europe, the low proportion of freshwater fish in per capita fish consumption indicates the preference for marine (including brackishwater) fish. East and Southeast Asia, where aquaculture is growing fast, this trend is quite evident when fish consumption is compared with South Asia. A majority of the cultured marine species are high-value and depend on high-quality complete diets. Driving forces that influence consumer behaviour and lead to an increase in the demand for various types of fish and meat are urbanization, lifestyle and dietary habits (Popkin, 1999). The forces that influence fish consumption, however, may vary between developing and developed countries. Delgado (1999) pointed out that in developing countries, increasing income and urbanization would be the leading factors for the increasing demand for fish and meat by 2020 (Delgado et al., 2003). Lubchenco (2003) claimed that the increasing demand in developed countries is driven by increased consumer awareness of the health and nutritional benefits of seafood, increased standardization and availability of products and cheaper prices. The relationships between income and urbanization and fish consumption are clearly important factors to be taken into consideration in the calculation of future fish demand and type of fish as there is a trend in urbanization globally.

The increase in population between 2005 and 2030 is expected to be 1.7 billion. This increase will be primarily accounted for by the growth in the urban areas of less developed regions, which is expected to reach 3.9 billion from 2.3 billion in 2005 (UN, 2007). Unlike developing regions, developed regions had already attained high levels of urbanization by 1950 (Table 16). It is projected that similar levels of urbanization will take place in the developing world. Between 2000 and 2030, Asia’s urban population will increase from 1.36 billion to 2.64 billion, that of Africa from 294 million to 742 million, and that of Latin America and the Caribbean from 394 million to 609 million. As a result of these shifts, developing countries will have 80 percent of the world’s urban population in 2030 (UN, 2007). By then, Africa and Asia will host almost seven out of every ten urban inhabitants in the world. With urbanization, people are increasingly drawn towards urban settlements and as both the level and distribution of income changes, the pattern of fish demand will change, with important implications for the demand for fish, and, in turn, implications for the type of feed used.

Consumers are as diverse in their consumption preferences as the fish products they consume. The increasing demand in developed countries, where urbanization is high, has been mostly for high-value fish species. Thus, the demand for high-value species, which consume high-quality feeds, may increase in developing countries as urbanization increases. Although growth in all aquaculture sectors is increasing (see Section 1.2), it can already be seen that exceptionally high growth rates have occurred in the production of high- value and carnivorous species such as freshwater swamp eel, mandarin fish, channel catfish, red swamp crawfish and freshwater swamp eel.

The increasing supply of high-value species is associated with decreasing market price of high-value species. The decrease in market price of high-value species may be attributed to the promotion of intensive practices in recent years to increase production, development of complete commercial performance diets and the competitive market environment. For example, the rapidly increasing production of whiteleg shrimp has led to price depression in the international markets (FAO, 2006). Similarly, farm-gate value for 15–20 g size whiteleg shrimp has steadily decreased from US$5/kg in 2000 to about US$3.00–3.50/kg in 2005. The market prices of European seabass and gilthead seabream imported to Italy from Greece dropped from €7/kg in 1999 to €4.6/kg in 2007 and €6/kg in 1999 to €3.8/kg in 2007, respectively (Fish Site, 2007).

Projected Global Aquaculture Production

2010-09-06T14:51:00.000-07:00

The first section of an FAO report looking at the impact of rising feed ingredient prices on aquafeeds and aquaculture production, looks at projected global aquaculture production. Written by Krishen Rana, University of Stirling, UK and Mohammad Hasan, Fisheries and Aquaculture Management Division, FAO. Projected Global Aquaculture Production with Contributions from Asia and Europe and the Implications for Aquafeeds

With stagnating global capture fisheries production, there is growing expectation for aquaculture to meet the shortfall of aquatic products and to cater to the growing demand of the increasing population. Predictions of the exact shortfall are imprecise: many forecasts have been developed based on a wide range of assumptions (Ye, 1999; Delgado et al., 2003; Wijkstrom, 2003; Dey, Rodriguez and Briones, 2004; Brugère and Ridler, 2004).

Delgado et al. (2003) with their International Model for Policy Analysis of Agricultural Commodities and Trade (IMPACT model) attempted to address the complexity inherent in creating a demand forecast by incorporating prices and their effects on consumer demand into the IMPACT model. Predictions were made using three main scenarios. Under the baseline scenario, which is the most plausible, “best guess” assumptions, global food-fish production was projected to reach 130 million tonnes by 2020 and aquaculture was expected to produce 41 percent (53.6 million tonnes) of this production. However, projected production at 2020 for all models (assuming a capture fisheries growth of 0.9 percent per year) has already been achieved (Table 4).

In their study for FAO, Brugère and Ridler (2004) adapted the studies of Delgado et al. (2003) for national predictions by considering government policy and production targets in national plans. Such national predictions were made for China, India, Indonesia, Thailand, Bangladesh, Chile, Viet Nam, the Philippines, Egypt, Brazil and Canada (Table 5).

The global actual average annual growth rate of 7.6 percent (from 2000 to 2006) (see footnote 2 in Table 4) and actual average annual growth rates of leading aquaculture producing countries in Asia (Table 5) suggest that all forecasted targets set for 2010 and 2020 by the forecast models in Table 4 are likely to be met.

These targets together with historic trends in species contribution to annual production can be used to forecast estimates of production tonnage and to predict trends in intensification of aquaculture practices for the various species groups farmed. These scenarios can help to understand the future demand and pressure on quantity and types of feed ingredients that may be required to meet production targets. For this purpose, the food-fish aquaculture production outlook projected to 2020 by Brugère and Ridley (2004) based on country national plans was used.

Contribution by species group to the forecasted aquaculture production (excluding aquatic plants) in 2020 is given in Table 6. To estimate the contribution of species groups to forecasted aquaculture production (excluding aquatic plants) to 2020 in countries listed in Table 6, the 17-year (1990–2006) average annual percentage contributions of the species groups (for Bangladesh, the 12-year average) were applied to 2020 production predictions.

Similarly, the contributions by species group were estimated for Europe based on the projected aquaculture production (excluding aquatic plants) forecasted by Failler (2008) in the 11 leading aquaculture producing countries in Europe (Table 7), which accounted for 88.0 percent of the total European aquaculture production (excluding aquatic plants) in 2006. Projected contributions by species group to aquaculture production (excluding aquatic plants) by 2020 in selected leading aquaculture countries in Asia

Projected contributions by species group to aquaculture production by 2020 in selected leading aquaculture countries in Europe

Farmers Blame Problems On Fry Imports

2010-08-30T09:46:00.000-07:00

MALAYSIA - About 50 siakap fish fry farmers at Kampung Pok Kiang and Kampung Keluang have been hit by a drop in demand since the beginning of the year.

To make matters worse, the fish have grown to more than 30 centimetres in length, more than twice the maximum marketable size of 10 to 13 centimetres, according to New Straits Times.

And, the bigger fish consume large quantities of expensive feed pellets which cost between 90 ringgit (MYR; S$38.68) and MYR112 per bag of 20kg.

"We are in a quandary as the maximum-sized fish fry normally fetch between MYR1 and 1.20 each. We cannot sell at that price now since the fish had grown so big and it cost so much to feed them," said farmer Ibrahim Muhammad.

He said there were more than a million fish that were past the marketable size in the two villages.

"Two months ago I had to sell 100,000 fish measuring around eight centimetres at 35 sen each to a wholesaler as I did not want them to add to the number of overgrown fish in my ponds. We are worried that the fish will soon die from lack of oxygen as the stagnant water in the ponds only have enough oxygen for small fry."

He said there were rumours that smuggled fish fry from Thailand, which sold at below market price had caused the demand to drop.

Another fish fry farmer from Kampung Keluang, Azmi Ismail, said he had more than 30,000 fish that had grown more than 10 centimetres in his 11 fish ponds.

"The market has dropped and there is no news from the usual wholesalers," he said, adding that he had not been able to sell anything since February.

He said he had to fork out about MYR1,000 every month to feed the fish and the cost would increase as the fish grow in size.

State Fisheries Department director, Zakaria Ismail, said they would try and help the farmers.

He said the department was finalising the quotations for wholesalers to buy the fish fry before supplying them to aquaculture farms.

"We will buy hundreds of thousands of fish fry through the wholesaler that has the best bid."

He told New Straits Times that he had not received any complaints about smuggled fish fry from Thailand but gave an assurance that all fish fry going through the Customs, Immigration and Quarantine points along the Malaysia-Thai border would be subject to stringent screening.

"Aquaculture farms risk getting unhealthy fish fry if they opt for smuggled fry," he said.

By courtesy of www.thefishsite.com

Aquafloat

2010-08-28T06:17:00.000-07:00

Aquafloat Induced Air Flotation (IAF) aerators & associated plant from PCPL provide an efficient & cost effective air flotation system for the removal of fats, oils, greases and other solids from industrial & municipal water and wastewater.

Aquafloat: The aquafloat in action Aquafloat is also suitable for the thickening of sludges from other water & wastewater treatment processes. Aquafloat is also suitable for the efficient diffusion of externally supplied gases (such as ozone or nitrogen) into liquid. Aquafloat can provide an effective and simple alternative to more traditional dissolved air flotation (DAF) plants. Operation The range is based around the Aquafloat IAF microbubble aerators. These aerators are capable of inducing large volumes of atmospheric air (or introduced gas) and presenting it via a specially designed rotating disc into a vessel or body of liquid as extremely fine microbubbles. These microbubbles effectively attach to solids particles in the liquid and float them gently to the surface of the liquid for concentration and mechanical removal, allowing clarified liquid to pass out of the vessel to discharge or further treatment. This aeration function is performed with very little induced turbulence making the Aquafloat an excellent unit for flotation applications. Simplicity Unlike more traditional DAF aeration, the Aquafloat aerator produces it’s air via atmospheric induction at atmospheric pressure. As such, there is no need for pressure vessels, recycle pumps and associated pipework and controls. System Sizing Aquafloat systems based around the Aquafloat aerators have been made to treat as little as a few hundred litres per day in a small tank, right up to single vessels treating 10 megalitres per day in large industrial oil refinery applications. Retrofit Capability and Flexibility The Aquafloat range of IAF aerators lend themselves to retrofit applications very readily. Where there is an underperforming DAF or existing flotation plant, a simple Aquafloat aerator installation can boost it’s operation immediately at low expense. This can mean immediate savings in operating consumables and discharge costs. Likewise, existing pits and separation vessels or clarifiers can be very quickly turned into flotation cells by the simple introduction of an Aquafloat IAF aerator or aerators. Multicell High Flow Units The Aquafloat has been particularly successful in very high flow applications such as oil refinery wastewater applications. This is effected by a special multi flotation cell plant design allowing for in-line controllable air quality in a number of sequential flotation cells. These systems can be provided to the very high specifications required by the oil and gas industry. Low Noise Operation The Aquafloat aerators are very quiet units, with aeration activity taking place below the surface of the liquid in any installation.No noisy air compressors are required for Aquafloat aeration. Australian Made - World Class The Aquafloat range is designed and manufactured wholly within Australia with local parts support – and has been exported all over the world. For further information or an application design using Aquafloat – please contact PCPL or your local Aquafloat representative.

Aquaculture Aeration

2010-08-19T07:45:00.000-07:00

Since a majority of all aquaculture problems, including disease, are caused by poor water quality and, in turn, most water quality problems can be resolved with proper aeration (oxygenation), it is clear that aeration plays a crucial role in this process.

Oxygen is the main limiting factor in both recirculating and traditional aquaculture systems. Less than the required levels lead to poor water quality, poor feed conversion ratios (FCR), reduced growth and increased mortality. With high energy prices, energy efficiency is becoming much more important when comparing aeration techniques and devices. Many of the traditional aeration devices like paddlewheels and aspirator style aerators have a poor track record of reliability and higher overall energy requirements. “Aerator Graveyards” have become a common sight throughout the industry as old aeration devices are replaced and discarded year after year.

Typical Aerator "Graveyard"

Colorite Aero-Tube™ aeration tubing can solve these problems with these distinct its advantages:

Reduces energy costs by up to 75%
Lack of moving parts provides a very low maintenance alternative
Maintains higher dissolved oxygen (DO) levels
Allows for higher stocking densities
Allows for higher feeding rates
Allows for more frequent feedings
Faster Growth and reduced FCR
Low start up cost
Low replacement cost

Aero-Tube™ technology has been used successfully with a wide range of Aquaculture species and in a wide range of production systems. Whether you are producing shrimp or fish, anywhere you are using traditional aeration systems to oxygenate your water, you can benefit from the efficiency and durability of an Aero-Tube™ system. Aero-Tube™ Technology

When planning for the proper aeration of an aquaculture system, there are many points to consider. Please feel free to contact us and we can help design and Aero-Tube™ solution for you.

To see the many options for using Aero-Tube™ Technology please visit Aero-Tube™ Products where you will find a solution that is right for you.

Recirculation Aquaculture System(RAS) is now common in Malaysia-www.stac...

2010-08-13T22:38:00.000-07:00

STAC's R&D Aquaculture Center has been appointed by China's Goldbill RAS as agent to promote the system to many parts of the world.

Live organic indoor Shrimp Farm project

2010-08-13T21:51:00.000-07:00

The Facts About Aeration

2010-08-06T02:27:00.000-07:00

Adequate aeration is arguably one of the most cost-effective management tools available to pond and lake owners to improve the quality of their aquatic resource. Although aeration is particularly important in smaller ponds (less then 3 surface acres in size), medium sized ponds and even lakes can also see dramatic improvements in water quality and water body health as a result of aeration. It is important not only to understand how aeration systems work, but also the difference between the types of aeration systems as well as the chemical and physical need needs of your water body. The most common benefits of aeration include: Increased dissolved oxygen concentrationPrevention of fish stress and mortalityRemoval of carbon dioxide and ammoniaMinimization of algae growthIncreased vertical and horizontal water circulationElimination of odorsImproved water qualityIncreased surface disturbance, thereby discouraging the successful development of mosquito larvae Many pond owners mistakenly consider aerators and fountains to be the same thing. This is not the case. There are distinct and significant differences between surface aerators and surface fountains. The three most common aeration methods for ponds and lakes are briefly described below.

Surface Aerators:

True surface aerators function by moving a large volume of water (800 – 1300 gpm.) a maximum of 3-4 feet into the air, thereby increasing gas transfer within the pond, inducing circulation and improving water quality. As a result of the massive amount of water being pumped into the air and splashing back down onto the water surface, a wave action radiates outward from the unit towards the pond or lake perimeter. Surface aerators are extremely effective in ponds which are less than 10 feet deep. The size, shape and depth of your water body will influence the size and quantity of surface aerators you need. A surface aeration system may be as simple as one unit or may involve several units strategically located around the water body. View our Aerator Models & Online Pricing

Surface Fountains

The primary objective of surface fountains is to create an aesthetically pleasing water feature. Similar to surface aerators, surface fountains function by pumping water into the air, thereby increasing gas transfer within the pond and improving water quality. However, a surface fountain pumps the water much higher (typically 4-15 feet), subsequently, the volume of water is significantly decreased (typically less than 250 gpm.) and, as a result, the aeration efficiency and gas transfer rates are dramatically reduced. The size and quantity of surface fountains is more often driven by aesthetics than the size, shape and depth of your water body. Often surface fountains are combined with one or more surface aerators to provide a complex water display feature while achieving superior water quality improvements. View our Fountain Models & Online Pricing
Subsurface Aeration System As you might expect, subsurface aeration systems are entirely different from surface aerators or fountains. Rather than pumping water into the air to increase gas transfer and induce circulation, subsurface aeration systems pump air into the water. Systems of “synergistic airlift diffusers” are placed on or near the bottom of the water body. Compressed air is pumped through underwater airlines to the diffusers, bubbles out of the diffusers, and rises through the water column to the surface. As the air rises, the bubbles expand, entrain the surrounding water molecules and “pump” them towards the surface, producing a gentle boiling of water and bubbles at the surface. These systems are extremely effective in destratifying a water body. In fact, the greater the depth the more efficient the system. Subsurface aeration systems are most effective in ponds with a depth greater than 12 feet or in lakes, and are not a cost effective option for smaller water bodies. Not all aeration systems are created equal. One must closely examine actual pumping rate, oxygen transfer rate and amperage draw of the motor before making a determination as to which system to purchase. For over 50 years, the Rowledge Pond Fish Hatchery has utilized aeration units from a wide variety of manufacturers, and we have even made a few of our own. We have found the PowerHouse surface aerators and surface fountains are the most durable, efficient and effective surface aeration systems on the market. We use PowerHouse surface aerators exclusively in our hatchery facility, and are proud to be their Northeast distributor. Rowledge Pond Aquaculture can assess your pond or lake and design, build and install an aeration system for you which meets both your property management objectives as well as the ecological needs of the pond.

Red Lobster Faring Just Fine in the Post-Spill World

2010-08-05T18:06:00.000-07:00

It remains unclear exactly how much damage BP's oil spill will do to the aquatic life in the Gulf of Mexico, but if you're worried about one of the worst environmental disasters in decades cutting into your $11.99 "festival of shrimp," you can rest easy. It turns out some of the country's most popular seafood restaurants have placed more emphasis on the second syllable of "seafood" rather than the first.

According to Rich Jeffers, a spokesman for Red Lobster, the casual-dining seafood chain gets very little of its shrimp from the gulf—or any ocean for that matter. Instead, it grows "farm-raised" shrimp in ponds throughout South America and Asia (Jeffers mentioned Thailand specifically), and at any given moment, the company has enough shrimp to meet the demand of all 700-plus of its locations worldwide for at least six months.

Of course, maintaining such a large shrimp supply isn't easy. In order to keep so many crustaceans alive in the densely populated farms—there can be up to 170,000 shrimp larvae in a single pond an acre wide and a couple meters deep—antibiotics are pumped into the water. Environmentalists have decried such practices, arguing that they can be harmful to the local ecosystems, but Jeffers says all their farms are closely inspected and certified by the Aquaculture Certification Council.

"What I would point out to you is the benefit of seafood sustainability," he says. "We're able to provide shrimp year-round, not relying on harvesting them from the ocean, which can only meet a certain demand."

Long John Silver's, the national fast-food chain, was not so forthcoming about the source of its shrimp, but it did tell NEWSWEEK in a short e-mail that is "not affected" by the oil spill.

So breathe a sigh of relief, cheap-fish lovers! Just as there is no end in sight to the consequences for the gulf, your endless shrimp platters will indeed remain endless.

A circulation model to investigate the movement of wastes from an Open ocean aquaculture site

2010-08-05T06:39:00.000-07:00

David W. Fredriksson*, James D. Irish, Dale A. Kiefer, Jack Rensel, and Frank OBrien

Department of Naval Architecture and Ocean Engineering,
United States Naval Academy
590 Holloway Road 11D, Annapolis, MD 21402
USA
fredriks@usna.edu A numerical circulation study of the western Gulf of Maine was conducted to investigate the movement of wastes from an open ocean aquaculture site. To examine the hydrodynamics of the region, a domain was built with the ADvance CIRCulation model with Gulf of Maine bathymetry, shoreline, island and open ocean boundary conditions. At the open boundaries, the model was forced with dominant tidal elevation components, including the M2, S2, N2, K1, O1 constituents, representing possible low flow conditions. These conditions are with no weather forced or geostrophic currents to further diffuse and advect material from the site, but just the regular tidal motions. Model predictions were compared with surface elevation and Acoustic Doppler Current Profiler (ADCP) measurements from a moored instrumentation platform at the aquaculture site. At the site, the ADCP collected velocity data sets oriented in the east-west, north-south and vertical directions at nineteen, 2 meter depth bins. The data sets were processed to obtain the velocity tidal components and reconstructed to form a time series. The reconstructed time series was then compared with the model results. Differences between the model and measured results were on the order of cm s-1

The numerical flow values from the large model domain were then used as input to the program AquaModel. AquaModel is a GIS tool that provides three-dimensional simulation of growth and metabolic activity of penned fish as well as the associated flow and transformation of nutrients, oxygen and particulate wastes in adjacent waters and sediments. AquaModel can be used to examine both the near and far field affects of individual or clusters of fish cages. The information can then be used to effectively site new farms, evaluate operation techniques, and plan monitoring programs.

Environmental Observations in support of Physical and Biological Modeling of Aquaculture Sites

2010-08-05T06:23:00.001-07:00

James D. Irish*, David W. Fredriksson, Dale A. Kiefer, Jack Rensel, and Frank OBrien

University of New Hampshire, Jere Chase Ocean Engineering Laboratory
24 Colovos Rd., Durham, NH 03824
jirish@whoi.edu Optimum design of an aquaculture operation depends on environmental conditions at the site, and requires a combination of observations, hydrodynamic modeling, and biological modeling. To develop and demonstrate this approach, a study was conducted for an aquaculture site in the Western Gulf of Maine about 12 km off the coast of New Hampshire in a depth of 50 m of water. The University of New Hampshire has been conducting open ocean aquaculture research at this site for nearly 10 years (http://ooa.unh.edu/). The research included measuring physical, chemical, and biological parameters important for aquaculture operations. Moored time series were made for about 9 months a year, and discrete water samples were taken monthly from spring to fall at the site starting in 1999 and continuing into 2008. Also, the UNH Coastal Ocean Observing Center has been monitoring the ecosystem in the region with monthly cruises. Their results supply additional information on the biological and chemical properties at the site. All these data are used for initializing and forcing the hydrodynamic model (ADvance CIRCulation = ADCIRC) and biological model (AquaModel).

The moored instrumentation measured water current profiles, temperature and salinity at the surface, mid-water (the 22 m depth of the fish cages), and near the bottom. Also, moored mid-water and bottom observations were made of dissolved oxygen, chlorophyll-a and turbidity. These observations provided information on oscillatory tidal currents (0.1 m/s oriented perpendicular to the coast) that help disperse waste products. Weather forced currents that advect material off site were quite variable with maxima of 0.5 m/s oriented along shore. These current observations were used to validate the ADCIRC tidal model (whose results were used to force AquaModel), and the currents also directly forced AquaModel.

The temperature and salinity follow a yearly cycle of warming in the spring-summer, and cooling in the fall-winter. Fall storms cause full water column mixing from early winter through early spring when thermal stratification is established, preventing vertical mixing. Temperatures cool to 2 to 4C in the winter and bottom waters warm to 10C in the summer while surface waters reach 22C. River runoff freshens the water in spring into summer to about 31 PSU with storm runoff spikes in surface waters reaching the low 20s. With the winter mixing, the water column salinity increases to above 33 PSU. Oxygen profiles are saturated or supersaturated from surface to bottom in the winter, but with the onset of spring stratification, oxygen below the pycnocline steadily decreases from fully saturated to about 70% saturated by the end of summer. The mid-water oxygen remained saturated into the summer, then also decrease into the 70% range by the end of summer. Suspended sediment and chlorophyll time series and discrete sample show river runoff sediments, spring and fall chlorophyll blooms. Red-tide blooms are also observed consuming oxygen. These water quality results were summarized into weekly averages and used to initialize and drive AquaModel studies of the site.

COMPARISON OF THE INTRA-HOST GENETIC VARIABILITY TAURA SYNDROME VIRUS (TSV) IN ACUTE AND CHRONIC INFECTIONS IN LITOPENAEUS VANNAMEI

2010-07-31T07:22:00.000-07:00

Jana Moerbe Rocker and Jeffrey M. Lotz*
Department of Coastal Sciences
University of Southern Mississippi
Gulf Coast Research Laboratory
Ocean Springs, MS 39564 USA Geographic genetic variability has been noted in Taura Syndrome Virus (TSV) and this variability has been used in molecular epidemiological studies. However, little is known of the genetic variability that exists within a single host during an infection. Quasispecies is a term originally applied to a mathematical model describing the genetic variability of RNA viral particles within a host. Quasi-species result from a balance between a high mutation rate and selection against the assumed less fit mutations. Due to the lack of a proofreading mechanism in RNA-dependent RNA polymerase (RdRp), the replication of RNA is an inherently error-prone process Therefore, the RNA virus exists within its host as a heterogeneous mixture of sequences: the master sequence (the most common and fittest sequence) and various non-lethal but less fit mutants.

Our objective was to determine whether TSV exists as a quasi-species by characterizing the genetic variability within individual hosts with TSV infections. Further we compared the genetic variation between acutely infected shrimp and chronically infected shrimp. We approached characterizing the genetic variability by cloning and sequencing numerous TSV samples from one infected host. The assumption is that the relative abundance of sequences among the clones reflects the relative abundances of sequences within the host. In order to reduce any sequence errors during the PCR process we used high fidelity polymerases. We employed the CP2 gene, which is used for most geographical genetic characterization, for our quasi-species analysis. Five shrimp with acute infections and five shrimp with chronic infections were used in the analysis. We attempted to clone 25 hemolymph samples from each shrimp for a total of 250 clones. Each clone was sequenced and the sequences were analyzed.

We found that individual shrimp were carrying TSV with considerable sequence variation in the CP2 gene. The mean mutation frequency was 1.7 x 10-4. The mutation frequency in chronic infections (2.18 x 10-4) was higher than in acute infections (1.2 x 10-4).

DETECTION OF SHRIMP TAURA SYNDROME VIRUS BY LOOP-MEDIATED ISOTHERMAL AMPLIFICATION USING A DESIGNED MULTICHANNEL PORTABLE TURBIDIMETER

2010-07-31T07:14:00.000-07:00

Wansadaj Jaroenram*, Assawapong Sappat, Wansika Kiatpathomchai, Tanom Lomas, Adisorn Tuantranont and Timothy Flegel

CENTEX Shrimp and Department of Biotechnology, Faculty of Science, Mahidol University,
Rama 6 Road, Ratchathewi, Bangkok 10400 Thailand. Email kungbtram@gmail.com Loop-mediated isothermal amplification (LAMP) is a nucleic acid amplification method that allows the synthesis of large amounts of DNA in a short time with high specificity. Since a white magnesium pyrophosphate (Mg2P2O7) precipitate is a characteristic by-product of LAMP reactions, a simple turbidimetric, end-point detection method was devised and tested for the detection of Taura syndrome virus (TSV) by spectroscopic measurement of the LAMP reaction precipitate. The device incorporated a heating block that maintained the optimal temperature of 63for the duration of the 25 LAMP reaction performed in a 0.2 ml tube. The temperature control and the turbidity measurements of this apparatus were sufficiently uniform for conducting LAMP reactions and monitoring the turbidity. The optimal conditions for TSV-LAMP was 6330 min. Using these conditions, LAMP-turbidity measurement revealed comparable sensitivity to that of LAMP-AGE, LAMP-LFD, nested PCR but showed 100 times greater than one step PCR. Cross reactions with other shrimp viruses as templates was not found, indicating that the LAMP methods were highly specific to TSV. Combining 10 min for nucleic acid preparation by a rapid method with 30 min for LAMP amplification followed by turbidity measurement resulted in a total assay time of less than 1 h compared to 4-8 h for the nested PCR. In addition, use of the turbidimeter yielded results immediately at the end of the LAMP reaction, without the need to open the reaction tube (i.e., avoidance of contamination) or to add further reagents. Thus, LAMP plus turbidity measurement constitutes a platform for the development of more rapid and user-friendly detection of shrimp viruses in the field without risk of amplicon contamination.

HAIRPIN-RNA EXPRESSION CASSETTE BY TWO-STEP CLONING SYSTEM AND ITS POTENTIAL AS AN IMMUNE STIMULANT IN SHRIMP

2010-06-08T07:32:00.000-07:00

Vanvimon Saksmerprome*, Patai Charoonart, Boonsirm Withyachumnarnkul

National Center for Genetic Engineering and Biotechnology, Thailand Science Park, Pathumthani and Centex Shrimp, Mahidol University, Bangkok Thailand
E-mail: vanvimon.sak@biotec.or.th We demonstrate an improved method for delivering RNAi-based immunity to large shrimp populations. Long sequences of double-stranded RNA (dsRNA) have recently been used to enhance viral resistance, through an RNA interference (RNAi) mechanism, in shrimp aquaculture. Since dsRNA-mediated knockdown efficiency of viral genes appears to be dose dependent, a large-scale production of dsRNA is necessary for antiviral/therapeutic applications of RNAi for shrimp farm operations. A new design of hairpin-RNA expression vector, followed by transformation into RNase-deficient E.coli HT115, offers a quick preparation of a large amount of long dsRNA (normally >300 nt). The hairpin RNA consists of a forward strand and a 100-base shortened reverse strand, and the unpaired 100-base region on the forward strand serves as a loop. This strategy reduces 3-step to 2-step cloning of hairpin construct into DNA expression cassette, thus bypassing difficulty in joining a small loop piece into a large carrier vector. A total RNA of ~4 mg is generally obtained from 100 mL bacterial culture.

The bacterially expressed hairpin RNA specific to RNA-dependent RNA polymerase (RdRp) gene of yellowhead virus (YHV) can induce antiviral immunity in Penaeus vannamei shrimp. Viral protection by exogenous dsRNA demonstrates the potential of dsRNA produced by 2-step-cloning hairpin cassette as an immune stimulant in shrimp (Figure 1). We investigate further if the putative viral promoters can be regulated by shrimp transcriptional activators. The hairpin specific to YHV is cloned into the viral promoter-contained plasmids, followed by intramuscular injection of the constructs into shrimp. We examine protection against YHV and level of viral mRNA after plasmid injection. Successful hairpin expression driven by such promoters demonstrates the potential of DNA-based vaccine for effective antiviral immunity in shrimp.

Evaluation of the Preservation of Shrimp Samples with Davidson’s AFA Fixative for Infectious Myonecrosis Virus (IMNV) in Situ Hybridization

2010-05-17T22:08:00.000-07:00

Thales P. D. Andrade*, Rita M. Redman, Donald V. Lightner
Department of Veterinary Science and Microbiology, University of Arizona, 1117 E. Lowell, Tucson,
Arizona 85721, USA

The potential negative effect of prolonged storage of shrimp tissues in Davidson’s AFA fixative on in situ hybridization (ISH) signal was demonstrated previously for Taura syndrome virus (TSV), which has a single-stranded RNA genome. In this study we evaluated if prolonged storage of infectious myonecrosis virus (IMNV) infected shrimp in Davidson’s AFA (Alcohol, Formaldehyde, Acetic acid) fixative will degrade its double-stranded RNA genome resulting in false negative ISH reactions. Twenty-one shrimp (3 g) specific-pathogen-free Litopenaeus
vannamei were used in this study. Three shrimp were used as negative control and 18 shrimp were inoculated with a tissue homogenate prepared from frozen IMNVinfected L. vannamei obtained from Brazil in 2003 (positive control). Shrimp were collected at Day 12 post-injection and fixed in Davidson’s AFA for five different preservation times (1, 2, 4, 7 and 10 days). After the different fixation times, the Davidson’s AFA was replaced with several changes of 70% ethanol until the pH was stable. IMNV lesions were confirmed in all positive control shrimp by routine H & E histology and ISH. Myonecrosis lesions were strongly positive by ISH at all five
preservation times evaluated. Hence, in the present report it was found that the length
of time (up to 10 days) in Davidson’s AFA did not have a deleterious effect on the
ISH reaction for IMNV.

_____________________________________________________________________
*Corresponding author. Tel.: +1 520 621 4438; fax: +1 520 621 4899.
E-mail address: thalespda@hotmail.com (T. P. D. Andrade), dvl@u.arizona.edu (D. V.
Lightner).