Aquaculture is one of the largest growing sectors around the world to supply food, and a substitute for wild caught fish. Aquaculture is profitable if optimal conditions and management practices are ensured in the fisheries, with close attention to sustainability and ecology. However, controlling diseases for the fish is one of the toughest challenges for the fish farmers. Disease also become an obstacle for aquaculture growth and has severe impact on both the economic and socio-economic development in many countries of the world. Addressing health issues has therefore become important for sustainable growth of aquaculture.
There are several factors that affect the health issues of fish and contribute to their diseases and illnesses. In the past, the major cause of spread of diseases and pathogens into aquaculture systems has been mainly through movement of animals and feed and animal products such as broodstock and seeds.
Impact of transboundary diseases
Transboundary diseases are highly contagious and can be spread from one farm to the others and to the nearby habitats and contaminate aquatic animals living in nature just as fast. “The impact of many of the transboundary diseases extend beyond the direct mortalities and production loses of fish farms.” says the Food and Agriculture Organization of the United Nations. They impact small scale fish farmers as well as global fish market through transportation and contamination of water. Fish are also subject to increased stress owing to environmental factors such as water quality, toxicity and pollution. Losses in aquaculture impacts the livelihood of fishermen who depend on fish farming, and also provide for the families and for the local economy and so, the whole community suffers losses through losses in production, income, employment, market access or market share, investment and consumer confidence; food shortages, industry failure or closure of business or industry.
Lost farm production to fish diseases such as epizootic ulcerative syndrome of fresh and brackish water fishes, penaeid shrimp diseases and a variety of other diseases causing losses in freshwater finfish pond culture and marine cage culture in 15 developing Asian countries was US$1.36 million. At the global level, combined estimated losses in production value due to shrimp diseases from 11 countries from 1987 to 1994 were about $3.01 billion. (Source: The Fish Site)
Irresponsible use of pesticides, herbicides, disinfectants and other chemicals also poses potential environmental hazards in addition to emergence of new diseases and contamination of water in the wild fish habitat. Moreover, poorly managed farms with intensive culture practices and feeding practices that increase pollution, waste and have adverse affect on local environment.
Like other farming systems, the aquaculture industry also has a fair share of trans-boundary aquatic diseases caused by viruses, bacteria, fungi, parasites and other pathogens. An effective health management program for fish farming needs to cover all levels of aquaculture activities from the production unit such as ponds, tanks, cage etc. as well as the entire farm and the area where the farm operates, at the district or zone level, to the national and international level.
The success of health management system of fish depends on communication and close monitoring of fish health in all levels of fish farming, production, packaging and transportation. Constant open communication and information exchange flowing in all directions is also necessary.
According to the Food and Agriculture Organization of the United Nations -Formulators of an effective health management program will always be confronted with a wide range of problems concerning:
Health Management Program Challenges
- human resources
- availability of information and data
- farmer knowledge base
- political commitment
- government priorities
- farmer/industry/consumer response
- varying degrees of interaction between the stakeholders;
- Environmental factors (river systems shared by many countries, contiguous marine coastal zones, etc.).
(Source: FAO Fisheries & Aquaculture)
Factors affecting fish health
- the increased globalization of trade in live aquatic animals and their products;
- the intensification of aquaculture through the translocation of broodstock, post larvae, fry and fingerlings;
- the introduction of new species for aquaculture and fisheries enhancement;
- the development and expansion of the ornamental fish trade;
- the enhancement of marine and coastal areas through stocking aquatic animals raised in hatcheries;
- unanticipated negative interactions between cultured and wild fish populations;
- poor or effective biosecurity measures;
- slow awareness on emerging diseases;
- the misunderstanding and misuse of specific pathogen-free (SPF) stocks (e.g. shrimp);
- climate change, and
- all other human mediated movements of aquaculture commodities.
(Source: The Fish Site)
Demand for Improved Aquatic Animal Biosecurity
There will be increasing demand for improved aquatic animal biosecurity. Health management of the aquatic animals has recently assumed high priority in many aquaculture-producing regions of the world. Concerns with contamination, chemical use for disease control or use of herbicides and insecticides, and use of unethical practices along with environmental impacts of overcrowded fish farms and the costs involved in disease prevention, has stimulated many countries to improve their laboratory facilities and diagnostic expertise, and advance technologies on disease control and therapeutic strategies in order to handle disease outbreaks more effectively.
Strategies for combating diseases
There are several strategies being practiced to minimize the risks of pathogens/ diseases associated with aquatic animal movements the world. There are also several voluntary or obligatory global agreements, codes of practice and guidelines that provide and implement certain levels of protection.
Codes of Practice include
- OIE’s Aquatic Animal Health Code;
- the Code of Practice on the Introductions and Transfers of Marine Organisms of the International Council for the Exploration of the Seas (ICES);
- the Codes of Practice and Manual of Procedures for Consideration of Introductions and Transfers of Marine and Freshwater Organisms
Both pro-active and reactive programs have become a primary requirement for sustaining aquaculture production and product trade. Responsible health management to minimize the risks of disease incursions brought about by the movement of live aquatic animals and their products is necessary.
Effective guidelines for aquatic animal health needs to be followed, or else risk of major disease incursions and newly emerging diseases will keep on threatening the sector.
We are going to give you more information about disease control and aquaculture health management in our future blogs, so please keep reading. Leave a comment below If you’ve got a question or comment.
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Source: WorldWide Aquaculture