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To prevent diseases, shrimp farmers should begin a program of prevention before obtaining the post-

larvae from a reliable hatchery, and it is recommended to realize a stan-dardized stress test of their quality. Hatcheries need to document (by certified diagnostic labs) that their broodstock and postlarvae are free of significant pathogens. If it is possible, farmers should verify the source of the broodstock.

In the farm, it is necessary to use an accurate health record system that could be used friendly. Data such as: postlarvae precedence, pond of cul-ture, production, survivals, weekly growth, and feeding rates should be recorded on it.

Health Management Programs to Identify and Prevent Diseases

For surveillance and monitoring of diseases or clinically ill shrimp, it

should be followed routine clinical examinations for signs of disease and pathogens (anorexia, soft-shell, black gills, lethargy, condition of the hepatopancreas, etc.). As a part of the routine, one should monitor stress, nutritional deficiency, poor pond con-ditions, water quality, pond bottoms, and clogged gills in the animal. Also observe the bird activity, and weak and dying shrimp on the trays, drains, or in samples.

Development and Implementation

of Shrimp Health Management

Programs at Shrimp Farms

By: William R. More*

The main variables that could affect Shrimp health are: Physiology of the host (Immunity), Host (spe-cies and life stage), Husbandry (post larvae quality, density/handling, production system), Environment (pond bottom, water quality, physical factors), Nutrition (feed quality and quantity, probiotics), and Pathogen (species/type).

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Important Examinations

As important clinical examinations of ill animals at farm or at laboratory, it should be an emphasis on microsco-pically observations on hepatopan-creas, gills and intestine. It could be needed, as a confirmation diagnosis, the bacteriologic and/or histologic examinations of sick shrimp. For the clinical examinations, it will be useful the records were it should be specified the history, source of larvae and juve-niles, feeds used, source of feed, and antibiotics used.

During sampling to denote stress, diseases, and presence of patho-gens, the farmer should be aware of plankton blooms, dead or stressed shrimp, low oxygen signs, shrimp with empty guts and fouling on shell, flaccid shrimp or with deformities, red discoloration of appendages on uropods, white appearance, opaque muscles or cramped tails, fouling and color of gills, black shells and super-ficial infections, color and relative size of hepatopancreas, shrimp with soft shells or heads, chronic localized bacteria infection, and muscle dege-neration.

Shrimp could be affected in its health with various stressors. The most common factors are: Rapid changes in temperature, pH and/or salinity, high concentrations of unionized ammo-nia, suspended solids and/or toxins, insufficient oxygen, high density (crowding), molting, deficient nutri-tion, presence of disease/parasites, and bad handling.

Diagnosis Identifying the Cause of the Problem or Disease

A diagnostic process is conformed by two interactive categories which are: Detection of the Agent, and Priorization of agents as to the relative contribution to the disease. A disease diagnosis depends on the ability to detect poor animal health and the presence of disease or pathogen at earliest stages, it is also important to recognize that disease have a time lag that complicates recognition of cause and effect relationship. Diagnosis also depends on the identification of reservoirs of infections and sources of contamination.

Application of Preventive Health Principles to Control Shrimp Diseases

To control shrimp diseases, an appli-cation of the preventive health prin-ciples should be adopted. For disea-ses of Biotic origin, farmers should establish a quarantine and restrict

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movement (prevention), disinfect and sterilize (hatchery production), disrupt parasite/pathogen life cycle, enhance species resistance, apply treatments such as chemoprophylaxis and chemotherapy, enhancement of hosts defences (immunization), and of course, have good stocking mana-gement practices.

For diseases of A-biotic origin, there must me a removal of oppor-tunity for exposure (proper handling and storage of feeds), give the shrimp feed supplements (nutrition), alter or improve the stock management practi-

ces in order to decrease stressors, and use of resistant species or strains.

In order to limit the introduction of diseases at the shrimp aquaculture faci-lities, there are some considerations to have in mind. First of all, it is needed a limitation of the access to the facility, try not to use wet foods and maintain a rodent/insect control program for

isolated feed storage facilities. Work on an “all in-all out” production cycle and if possible, develop closed or semi-closed water recycle systems so that water exchange could be mini-mized; contemplate a proper filtration of incoming water. Keep reservoirs without any form of life, drain and

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mation of the disease, and a specific reason based on a sound clinical basis that the disease will respond to the antibiotic to use. Then you can use the antibiotic according to the instruc-

tion on the label and with a proper withdrawal period. Be sure that the antibiotic is not banned for local and

market destiny regulations.

Conclusions

Shrimp farmers need to develop preventive health programs before getting a disease in the

system. Never forget to establish and follow a

program to promote ani-mal health in the facility and

a population of disease free and healthy animals. Train your person-nel for surveillance and monitoring of animal health to provide advance warning of problems. And if disease is already on shrimp, establish a rigid program to fight it.

*More & More Consulting Services, Inc.

dry them (also canals and ponds), and notify your neighbors when you are doing that or harvesting. Hold your postlarvae for a predetermined time in an acclimation place or nursery and try to use specific disease resis-tant animals (SPR). Destroy or cook shrimp waste products from proces-sing plants; develop a disease moni-toring program to fit your individual needs. When possible, use feeding trays. Limit the escape of the shrimp at harvest, and for any reason, never release them into the wild.

Verification of shrimp diseases, stress and pathogens.

If the farm is already infected, there are also some strategies of farm mana-gement that can be used to reduce the damage. Stock your juveniles grown in raceways or another type of bio-secure environment. Stocking densities must take into considera-tion the prevailing disease conditions and risks to production success. Consider that water exchan-ge provides a high risk for disease outbreaks when virus diseases are pre-sent. Maintain a good feed management and bring farm managers trained to confirm the disease and identify the problems.

Some other alternative mana-gement strategies include the perio-dic dry outs and seasonal cropping; lowering of the density culture in seasons when disease risk is highest. A supplemental aeration with no or limited water exchange could help.

In order to make use of antibiotics, one should need to have a confir-

When a disease occurs, you must define the problem and determine when the problem originally occurred.An accurate diag-nosis is required for proper treatment

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