Impacts of commercial drugs and chemicals on aquaculture in north-east Bangladesh

Abstract

Bangladesh has a lot of water bodies which are very suitable for fish cultivation. Fish farming is increasing every year in Bangladesh. With increasing aquaculture, the use of various chemicals and drugs are also increasing day by day. This study was designed to find out the chemicals and aqua drugs used in aquaculture and their impacts on fish production in north-east part of Bangladesh. It is rich in natural and farmed fishes. The study was conducted between March 2018 and April 2019 using prearranged questionnaire. Data was collected from administer to operations of many farms groups, such as markets survey, focus group discussion with nursery and culture farmers, farm managers, fish hatchery owners, fisheries professionals, retailers and whole sellers of aqua products and representative of pharmaceutical companies. Fish farmer’s usually used a variety of aqua products to solve various problems. These drugs and chemicals included a variety of disinfectants, natural food enhancers, and harmful insecticides, various parasite, harmful gas remover, artificial oxygen releasing products, predatory fish killer, and fish control products etc. The Study observed that168 types of different aqua products were commonly used for various purposes such as, pond preparation, water quality management products, fish poisoning or disinfectant, water and soil probiotics ,insect killer, Stress reducer, digestively enhancer, chemicals use as disinfectant , gas remover, growth promoters, oxygen supplier, algae killer, predator killer and fish disease recovery or antibiotics in this region. Lime, salt, zeolite and probiotics were used common products for pond preparation and water quality management. Rotenone, aluminium phosphate toxin tablet and bleaching powder were used to clean the pond when fish toxicant of which rotenone was broadly used in the nursery and grow out ponds. Though aluminum phosphate endrin and phostoxin were forbidden fish toxicant but these were frequently used in this region. Farmers were using more these products to culture fish in more density in less space. Beneficial aspects such as increased in production help to prevent feed wastage and maintain a good pond environment. There were some harmful aspects in farmers such as increasing the cost of production by using more drugs. Some drugs were harmful to human health. Excessive use of some chemicals including potash reduces the growth of fish, destroying the natural food etc. The study observed that 80% farmers were followed in poly culture systems. The study indicated that 88% and 90% of the farmers use the liming and drying process for culture pond preparation respectively. The study found that 98% farmers eradicated the predatory fish and insects from the pond. The study found that 90% of the farmers collected their fish seed from hatcheries where only 10% collected them from the wild. In the management process of the ponds, 98% of the farmers used fertilizers. The study found that 99%, 90% and 95% of the farmers stated that they regularly monitor their pond, check the water quality of the pond and feed the fishes. Most of the farmers received FCR 1.5 that indicated feed cost was too much higher and overall production cost also high. Farmers in the north-east were aware of the FCR of their used feed. According to them the average FCR is 1 to 1.5 but different feed companies’ referred to their FCR as 1.2. 98% farmers used some kind of banned chemicals which are very harmful for culture pond and bad impacts on its productions. The study showed that 80% farmers were benefitted to use chemicals/ drugs and got high production. They used a variety of chemicals, even antibiotics to prevent and cure fish diseases. Farmers collected all these chemicals, medicines and feed from various companies. But the best part is that the farmers of this region were becoming more and more aware day by day. They were collecting good quality fry and feed .In the study area 98% of the farmers were regularly taking care of their ponds and fish health. The study found that 90% of farmers had no water exchange facilities and they apply feed two to three times per day. The used of impure chemicals is high due to the rapid degradation of the water environment due to excess feed waste. Due to these reasons the farmers were economically disadvantaged. The study indicated that 98% of farmers said they were interested to use various drugs and chemicals. Only 2% of farmers did not use any types of drugs. In the study area 85% of farmers responded that the use of drugs and chemicals increase their fish production which had a huge impact on high production. In the study area 90% of farmers answered that their production has increased more than before in modern fish farming using drugs and various chemicals. At the time of data collection, it was observed that farmers using regular chemicals, probiotics and drugs to keep their pond environments were good. The color, smells and the presence of natural food were much better. Those that were regularly using variety of chemicals and probiotics did not have any bad smell at the bottom of the pond which was conducive to fish production. Farmers thought that regular use of drugs reduces the incidence of the diseases. Examination of various parameters during data collection showed that regular use of probiotics and chemicals in all ponds had a good pH, ammonia and oxygen which lead to higher fish production. The study showed that they are generally unaware of the use of chemicals, appropriate dose, application method, and proper products knowledge and health hazard use of chemicals is the main problems in north- east region. The study observed that Feed, fry and aqua products price were so high and on the other hand fish selling price was very low. The study also observed that the farmers were suffered by low quality feed, seed and drugs which had adverse impact on the aquaculture production as well as environment. Government should take some step to reduce the feed, seed and aqua inputs price and ensuring quality. Aqua farmers required awareness training program about adverse and benefits of drugs and chemicals of modern culture technique. Aqua culturists and environmentalist require raising their awareness of the implications of the use of these products. Users should be aware of the health consequences of chemical misapplication.