Introduction

This issue of our newsletter deals with Bio-security concerns in the shrimp industry and shrimp trends in Latin America along with a Q&A about water quality issues our technical staff experiences most frequently. We have decided to highlight various environmental areas in our newsletters. Future newsletters will feature such areas as wastewater treatment, soil remediation, commercial and institutional treatments, consumer product treatments - basically all the various treatment areas we are involved in. If you have specific requests, please email them to us and we will be happy to consider them for upcoming issues.

Shrimp Culturing Trends in Latin America

1) Major producing countries: Production Mathematics of 2004:

Major shrimp farming producing countries of Latin America are Brazil, Ecuador and Mexico. All three have shown steady production increases from 2002 up to first half of 2005 with the exception of Brazil, who had a drastic reduction in 2004. Ecuador and Mexico have increased exports to USA from 2002 to 2004 by 26 % and 19 % respectively. Comparing first half of 2004 and 2005 exports from Ecuador and Mexico to the USA, both countries kept increasing 22 % and 9 % respectively, showing a steady increase with trends to continue. Brazil was also increasing exports to the US from 2002, but in 2004 had a significant decline in exporting volumes to USA due to closing of farmed area being hit by diseases, and Anti-Dumping Tariff issues. But Brazil reacted in increasing its sales to Europe (2004) to partially compensate lower exports to USA. Comparing first half of 2004 and 2005 exports from Brazil to the USA, a decline in volume was found at 64 %. In South America, production volumes of Ecuador tend to maintain increasing pace, since its industries have already started to recover from diseases. Brazil may stay low for a year, or up to the time its industry reorganizes efforts to control diseases and starts increasing farming area and productions again. Smaller producing countries of Central and South America have declines in export volumes to the USA when comparing first halves of 2004 and 2005. Such is the case of Honduras (-39%), Guatemala (-81%), Belize (-48%), Nicaragua (-11%), Panama (-6%), Venezuela (-24%), Colombia (-16%). For the same period, Peru increased exporting volumes to USA in + 42% due to increase in stocking densities and farmed area along with improved pond management.

2) Production Problems of the 90's:

Up to date, the most harmful saltwater shrimp disease ever experienced in the American Continent has been the White Spot Syndrome Virus (WSSV). It came from Asia in 1995, affecting shrimp farms near the Gulf of Mexico, and later off the coast of South Carolina (APHIS 1999). In the Pacific cost of Central America, the WSSV was documented in 1999 (APHIS 1999), and in 2005, Brazil was finally affected (CEI 2005).

3) Awareness of culturing problems:

The WSSV has widely spread in both coasts of the Americas, but its virulence has naturally decreased over the years by region, which is demonstrated in generalized improvement of productions. Nonetheless, WSSV is still causing mortalities, and new emerging diseases are contributing to losses. Previous diseases like Taura Syndrome Virus (TSV) that appear originally in Ecuador are now colonizing new geographical areas like Venezuela. Infections between countries, along with poor management practices resulted in huge reductions of farmed area with detrimental results to local economies.

4) Understanding Best Farming Practices (BFP)

The Latin American shrimp industry facing so many problems was forced to improve managing techniques and biosecurity throughout the steps of production and processing. Efforts have resulted in minimizing mortalities, increase productions and sustaining of the business. An overall production approach has been to use domesticated shrimp, stop water exchange, and improve feed quality and feeding management. Reduction of N and P nutrients input into the system has been done by optimizing fertilization, feeding quantity and reduction of % protein in feed through the culture. Equally important attention has been provided to the use of biological products to balance water and soil, between other actions.

5) Use of Probiotics is helping:

Starting the second half of the 90's, Latin American shrimp farms and hatcheries increased the use of probiotics after finding promising results. Up to 2005, use of probiotics is widely used due to increase knowledge of benefits and application protocols, synchronized to better farming practices. There are different types and brands of probiotics, and probiotic quality and field assistance provides the best benefit to shrimp farmers in terms of productions and Return of Investment (ROI).

Bio-Pure has been successfully marketing several probiotic products worldwide for improving both productivity and survival rate. In Latin America, some countries include Mexico, Peru, Brazil, Ecuador, Belize, and Venezuela. Bio-Pure products provide support to prevent bacterial infections, improve water quality and sustain surrounding environment from massive pollution. Use of these products should facilitate organic shrimp farming by eliminating the need of using antibiotics and other chemicals. Specialized technical assistance, training and field support are provided.

6) Antibiotic treatments and residues kill the export:

It is a fact in various ways. Antibiotic overexposure to shrimp has increased the appearance of antibiotic resistant pathogenic microorganisms, which caused contaminations and diseases at various phases of the shrimp cycle with subsequent mortalities and low productions and exports. This was widely experienced from the beginning of the 90's and up to date. In another way, traceability of antibiotics in exported products has led to blockage of exporting products by industrialized importing countries. This tends to decrease shrimp prices in producing countries which results in closing of farm areas and reduction of exporting volumes.

7) Organic Shrimp Farming:

It is a relative new trend in Aquaculture that takes more importance year to year. Consumers are more aware that quality of what they eat is important for their health, and demands traceability of goods for purchasing. Organic shrimp farming relies in specific culturing rules which results in culturing protocols and productions that do not harm the environment, humans, animals or plants. Since antibiotics are expressly forbidden in this type of farming, the culture also relies on natural products like probiotics to sustain shrimp health, water stability and higher and higher productions.

8) High Density Farming in Greenhouses:

It seems to be the best method for securing excellent and cost-effective productions in warm areas, even operating costs per area are higher. In such controlled environments, biosecurity can be achieved and maintained much better. High temperatures assist in preventing diseases and in increasing growth, survival and productions. We can see Peru leading Latin America by having a high percentage of culture area with greenhouses, along with improved farming practices and average high shrimp productions (7 Tons/Ha). Biological products are on continuous use for assisting this type of culture.

9) Quality is critical:

The Latin American Shrimp Farming and Processing industry is adjusting itself to the constantly increasing demands of the market for shrimp quality. Improvements are applied by all actors in this business, being hatcheries, shrimp farms, feed and shrimp packing plants, between others, since all contribute to a better quality of shrimp meat and flavor at time of retail marketing and cooking, which results in higher demand of that shrimp.

10) Sustainable Shrimp Farming in Latin American Countries:

In the past years, the Latin American shrimp industry after abusing the environment and culturing systems experienced many times failures in terms of productions and socioeconomic impacts. Nonetheless, the industry has been very dynamic in understanding the origin of problems and had begun correcting approaches. Main approach was to research and develop managing practices that will not return to destroy the industry.
Now, the industry is aware of the importance of biosecurity, good Post Larvae quality, of not abusing the water and soil carrying capacity, and the reduction of water exchange. Also, the industry understood the huge importance of feed quality and its management during culture, and the importance of not adding antibiotics but adding best quality probiotics, between other important factors. All approaches are going towards sustaining productions that will not harm the farm environment, surrounding areas and human health. All factors will provide overall better results that will improve the socioeconomic situation of each country.

Commonly asked questions in shrimp farms:

Q: Why I can not control excess of phytoplankton and toxic nitrogenous compound levels?
A: When excess of NH3, NO2 appears in the pond water, it is a sign that Nitrogen (N) has been wasted from feeds to water, and was not used by shrimp to grow. Nitrogenous compounds serve as the source of N to sustain phytoplankton growth. If Phosphorus is available at specific quantities, phytoplankton and/or cyanobacteria blooms will develop. Initial or in excess increment of NO3 and/or toxic compounds NO2 and NH3 is the key to know it is time or urgent to decrease % protein in feeds and/or check feeding rates per day. Through adjustment of % protein and feeding rate, along with the application of premium quality biological products with heterotrophic bacterial cultures, the excess of such nitrogenous compounds will disappear, and phytoplankton could not grow in excess.

Significance of Biosecurity in Shrimp Farming

Shrimp Consumption in USA :

Shrimp is widely consumed in this country and most of it is imported. In 2005, total shrimp imported reached >1.1 Billion pounds (new record) with a value of $3.7 billion. At the retail level, the average per capita amount spent on imported shrimp is over $12. Major shrimp producers are Asian countries and Latin American countries with significantly differing production conditions. Because of the wide popularity and almost total dependence on importation, it is critical to understand the role of biosecurity in shrimp farming operations for safety and security of the consumers.

World production of shrimp hovers around 4 million metric tons with farmed shrimp accounting for >2 million metric tons or >50% of world production. In the last 30 years, shrimp farmers have doubled the world's supply of shrimp and aquaculture has become one of the fastest growing industries in the world.

Definition:

Biosecurity in aquaculture is the protection of fish and shellfish from infectious agents (viruses, bacteria, fungi or parasites). Mortality due to diseases and decreased production due to infections are major factors for economic loss but also a serious food safety concern for the consumers. In addition, as the density of shrimp in intensive farming becomes more concentrated and actively managed, the probability of individuals coming into contact or becoming a source of potential pathogen is much greater. Thus, it is critical to implement appropriate safeguards in production facilities to protect the health of aquatic animals. These safeguards include diagnostics, disease prevention, disease control etc., which are imperative and should be enforced through Ecologically Sustainable Development (ESD) strategies.

Biosecurity in Shrimp Farming:

At the shrimp farm level, biosecurity refers to producing healthy shrimp in a well-controlled environment that excludes the introduction or propagation of unwanted organisms and includes the prevention of escape of organisms back into the natural environment. Since this is not always possible, the goal may have to be modified to prevent, eliminate or control infectious diseases within the facility.

There are numerous potential sources of entry for an infectious agent into an aquaculture facility. These include additions of new stock fry, post larvae, juvenile shrimp and broodstock; contaminated water or feed, humans, animals or equipment, and sub clinical (asymptomatic) carriers within the existing stock (production shrimp or broodstock). Each of these potential sources needs to be evaluated and continuously monitored to prevent the entry of infectious organisms into the system. Thus, a sound biosecurity program for a shrimp farming facility would incorporate a) disease prevention, b) disease monitoring, c) managing disease outbreaks, d) cleaning and disinfection between production cycles, and e) general security precautions.

Biosecurity measures:

Disease prevention includes the methods used to prevent the entrance of all potential pathogens into the production facility. One of the principle methods to avoid the introduction of certain pathogens is to procure shrimp/post larvae from sources selling certified specific pathogen-free (SPF) stock. Though this does not eliminate all potential pathogens within the supply, it does help reduce the risk on introducing the major pathogens of shrimp. Unfortunately, only a few species of shrimp are presently sold in this manner. Thus, many producers have established in house brood stock or spawning facilities to provide stock for production facilities. In addition to disease avoidance, a rigid quarantine program should be incorporated to isolate any new arrivals at a facility. The time interval required for a quarantine period can be closely monitored for clinical signs of disease, sampled for diagnostic health techniques, and treated if warranted. Vaccination is another means of disease prevention in aquaculture.

Another important method of disease prevention includes providing a pathogen-free water source. Thus, an “infected” water supply may require modern technology (mechanical filtration, chemical treatment, UV filtration, ozonation, use of biological products for waste digestion etc.) to make the water acceptable for a biosecure facility. Finally, optimal management techniques, including stocking densities, nutrition, and genetics are essential for all cultured species to develop and maintain an optimal health and immunological status to fend off any potential pathogens.

Disease monitoring should be an essential part of any biosecurity program. This consists of regularly scheduled health evaluations of all stock in an aquaculture facility. Depending on the particular situation, this may include either lethal or non-lethal sampling or both. Non-lethal techniques may include gill, shell and immunological assays, while lethal sampling may include bacterial cultures, viral isolation and histopathology. Though none of these assays can completely guarantee that there are no potential pathogens in a shrimp population, they do help reduce the risk of maintaining a pathogen in a population. An initial or pre-purchase health evaluation of new stock will establish baseline information about the shrimp, and can provide valuable information if a disease occurs in a facility. Periodic monitoring can also help determine the number of individuals within a population that are infected, and the level or intensity of infection within that population.

An important area of disease prevention and control that is often overlooked in the aquaculture industry is disinfection. Routine disinfection is used to reduce the pathogen load in a facility, thereby reducing the risk of spreading an infectious organism between groups of shrimp in a single facility. For example, providing an adequate number of containers of appropriate disinfectant for nets and other shared equipment is one method used to inactivate potential pathogenic organism. However, having separate equipment (nets, feed buckets, water sampling jars etc.) for each production unit would be optimal in helping to eliminate the risk of contamination between production systems. Disinfecting live-haul vehicles after delivery of stock to farms or other facilities also helps to avoid bringing back a potential pathogen from these other sites. In addition, cleaning and disinfection of the aquaculture facility and associated equipment between production cycles is very important and helps reduce the risk of spreading and infectious agent from one production group to the next.

Good Aquaculture Practices (GAP)

Aquaculture exports are continually swamped by new requirements related to labeling, traceability, bio-terrorism, assurance of product safety, risk assessment, antibiotic residues , harmful chemicals etc. This has led to the creation of GAP, which is tremendously focused on pre-harvest phase for improved production, food safety assurance and preservation of environments. Emphasis has been placed on farming practices like pond preparation, disinfection of water, aeration, temperature, pH, alkalinity, salinity, feeding issues, sludge reduction, lowering water exchange, removal of nitrogenous compounds, use of antibiotics, use of probiotics and so on.

HACCP in Aquaculture

It is believed that GAP alone will not be adequate but by the implementation of HACCP in aquaculture. This integrated approach primarily for food safety also provides adequate focus on the pre-harvest phase for safe, profitable and sustainable shrimp farming. Under the HACCP program implementation, critical control points are determined and corrective steps are taken before it becomes a hazard. Routine screening of shrimp samples using PCR (polymerase chain reaction) technology has come to play an important role in managing viral diseases in shrimp culture.

Probiotics in Aquaculture:

It has been suspected for quite some time that microorganisms play important roles in overall aquaculture practices. Positive aspects of microbes include their potential to provide additional nutrients thereby reducing feed costs and maintaining desired conditions within the culture environment. Recent studies indicate the use of microbes as probiotics in culture systems for stability and control of microbial populations, maintain stable water quality parameters, eliminate the presence of stressors like NH3, NO2, NO3 etc., prevent bacterial infections caused by Vibrio and other eubacterial pathogens, viral infections etc. Mixed cultures of gram positive, spore forming Bacillus species occur naturally in the intestinal tracts of prawns and known to produce a range of antagonistic compounds against bacterial pathogens. They are considered true probiotics in shrimp aquaculture. An increasing body of research indicates that selected microorganisms like Yeasts (Saccharomyces cerevisiae, Candida utilis, Kluyveromyces marxianus) and yeast products offer several benefits: improving feed attractability, supporting growth by producing vitamins, minerals, nucleic acids and stimulation by beneficial gut flora. In addition, the immunostimulatory properties of yeast cell walls (beta glucans and mannans) to induce non-specific immune response in shrimp, is very beneficial to survive in the overwhelming presence of bacterial and viral pathogens. Live yeast can function as probiotics adhering to and colonizing the intestinal mucus, eviction of pathogens out of the hepatopancreatic system, produce critical nutrients that can impact growth like vitamins, minerals, and polyamines involved in many biological processes.

In conclusion, general biosecurity precautions need to be established from each facility to help support the activities of both disease prevention and disease control. A manual of standard operating procedures (SOP) should be assembled to provide a set of standard rules for biosecurity measures and disease monitoring. This should include such things as facility design, facility flow for both personnel and stock, rules for limited or restricted access to facility, required visitor log book, disinfection procedures for personnel and equipment, a waste management plan, pest control guidelines, and general husbandry and management procedures (BFP). This manual should also incorporate procedures to be instituted if a disease is detected or an outbreak occurs. Record keeping ( traceability) is paramount to the success of any biosecurity program because it can provide accurate historical information about the health status, weight gains, feed consumption, vaccinations or treatments, and management practices of the facility.