Fish farming is one of the fastest growing industries in India, but with all of the fish health problems plaguing the industry, are Indian farmers really prepared to handle the increased demands? Recent surveys in the States of Alabama, Arkansas, California, Colorado, Florida, Hawaii, Kentucky, Maryland, Massachusetts, Minnesota, New Jersey, New Mexico, North Carolina, Oregon, Pennsylvania, South Carolina, Texas, and Washington show that pollution is one of the leading causes of fish kills in the ponds and lakes managed by individual farmers. In both the Raichur & Mysore study (Case Studies 2 and 3) none of the irrigators surveyed faced total crop loss due to water pollution. However, most of the irrigators were not aware of fish health problems, which can result in reduced yield and even kill the fish in the pond.
The key to managing fish health problems is to make sure that your farmer has a well established fish health problems response plan in place before introducing any new fish into the pond. The first thing you need to look for is a pH gradient within the pond. An acidic environment will cause the fish to die out, as the fish will be unable to use their immune system to fight against the presence of ammonia and nitrite. This is because fish do not properly process the ammonia and nitrite to their hormones, causing premature death of fish.
There are also several fish health problems caused by introduced predators such as birds, cats, raccoons, and skunks, which will also have an immediate impact on productivity and cause fish kills. In the Raichur/Mysore study, almost half of the farms surveyed suffered from multiple losses, with nearly a third of these losses caused by raccoons. In the case studies, some farmers were not aware of how raccoons were becoming a threat to their business, leading to multiple cases of damages and deaths. This highlights the importance of farmers being aware of what their food supply may contain and taking steps to avoid introducing new predators to their ponds.
Another issue facing farmers is the impact of mass mortalities at sea, which occur each year due to poor fishing techniques, as well as increased pressure from cities to catch more fish for market. Mass mortalities will impact fish population by impacting the productivity of both bottom-water and surface-water habitats. Although it is not known if this will increase losses with fish health problems, it is something that every pond manager should know about and deal with.
One of the most recent diseases affecting marine life is chronic mortalities, caused by a bacteria known as P.Acnes. This bacterium has been steadily gaining a reputation as one of the biggest causes of disease outbreaks among marine life over the past twenty years or so. This bacterium feeds off of dead, dying, or dying marine animals, and is responsible for many of these disease cases, affecting a wide range of aquatic systems. This is especially the case in coastal systems where a lot of waste and debris comes in, combines with the warm temperature and freshwater conditions to allow these bacteria to flourish, increasing the chances of an outbreak. Fortunately, there are methods being developed to stop this rapid spread of this disease.
Disease spreads very quickly, often being missed by managers in the field who have been concentrating on other things. If this problem is not recognized, it can rapidly spread, affecting a wide area in a very short time. Many of these diseases have been linked to poor quality and quantity of stocks, both of which are becoming harder to control with the use of culture systems. Diseases caused by parasites, algae, and bacterial disease are also on the rise, with this increasing the pressure on both managers and aquaculture industries alike to find ways to deal with these issues.