Agrochemicals used in freshwater aquaculture in Jhenaidah district, Bangladesh

: The present experiment was conducted in order to investigate the use of agrochemicals in freshwater aquaculture with emphasis on fish health management. The selected area was Mahespur upazila under Jhenaidah district and the study duration was six months. The main group was fifty fish farmers and the data were collected through interview with fish farmers and key informants (chemical seller). Ten categories of chemicals were identified that are used by fish farmers for various purposes such as pond preparation, water quality management, controlling diseases, supplying oxygen, killing fish predators, Ten pharmaceutical companies were found to provide the agrochemicals to fulfill the farmers need. These companies are Novartis Anmal Health Ltd, Fishtech (BD) Ltd, SK+F BD Ltd, Renata Ltd, ACI Animal Health, Opsonin Pharma Ltd, Eon Animal Health Products Ltd, Square Pharmaceuticals Ltd, Sciencetech Agro Industries Ltd, Rals. In the study area some kinds of diseases were founded such as Epizotic Ulcerative Syndrome (EUS) in Rohu ( Labeo rohita ), Catla ( Catla catla ), Mozambique tilapia ( Oreochromis niloticus ), Black spot in Stinging cat fish, skin diseases, gill damage, tail and fin rot in Yellow tail catfish ( Pangasius pangasius ). For highest stocking density tilapia and pangus were mostly affected by diseases in winter. Farmers use various chemicals such as for water quality management agriculture lime, Geotox, JV Zeolite, Mega Zeo Bio, Aquakleen and Biomin, as antibiotic they use Novamix 101, Erocot, Captor, Oxysentin 20%, Renamycin, Aquamycin and Oxysentin 20% are antibiotics with different trade names were seen in the market as well as used by the fish farmers in the study area. The fish farmers use a wide variety of disinfectants in freshwater aquaculture. Timsen, Polgard plus, Formalin, Bleaching powder, EDTA are found available in all the shops of Mahespur. Formalin is used to control protozoan diseases. Virex is used to destroy virus and bacteria. Fish farmers use oxygen suppliers to increase the oxygen level in the water body. Oxidizing agent, hydrogen peroxide are major active ingredients of such chemical. The recovery of fish diseases was found 80-90% in the study area. During field observation many problems were identified in case of using agrochemicals which included lack of skill and knowledge of farmers about the application, withdrawal period of agrochemicals and drugs and some adverse effects on fish and human health.


Introduction
In Bangladesh the production of aquaculture is increasing day by day through diversification (Mahmud et al., 2012). In the past, people depended mainly on wild fishes and other natural resources but catches have declined due to increased fishing effort and range of other anthropogenic pressures (Apu, 2014). As a result, aquaculture has grown rapidly to fill the gap. Maheshpur is an Upazila under Jhenaidah District. Fish culture mainly dependent on the input of formulated feeds and the application of agro chemicals. But different types of diseases

Educational status
About 6% fish farmer had no education. About 35% people can only sign only and 80 % were gained their primary education only. 5% fish farmer had education up to S.S.C level only. Between them 4 % fish farmer had gained higher education and acquired bachelor degree ( Figure 3).

Pond ownership and land holding status
Among 50 fishermen of my study areas about 75% farmers having single ownership and 25% farmers having multiple ownership. About 82% fishermen had own land and the other farmer about 18% had culture others land (Table 1)

Occupation
The fishermen of my study area had more than two occupations. They all were not involved with fish culture completely. Fish culture was the main occupation of the maximum fishermen the percentage was about 94%. Besides fishing some people involved with other profession as their secondary occupation. The percentage of these kinds fishermen was about 6%. Some fishermen found in the study areas that they become involved with the secondary occupation when primary occupation means fishing cannot provide full time employment. Most of them were involved with agriculture besides of fishing.

Sources of credit
In my study areas it was found that about 76% fishermen used their own money for their culture practice. About 8% of them received credit facilities from the bank and others were involved with different NGOs for their credit facilities purposes. The amount of their loan was minimum 10,000BDT to 60,000 BDT respectively. The mean of loan was 32083.33±15733.33. They had to pay the extra interest was about 650BDT to 9,000BDT.

Training status
About 75% fishermen of my study areas had no formal training. They were gained experience by self-practice. About 25% fishermen were getting formal training from the Upazila Fishery office with the help of Department of Fisheries (DoF).

Crop farming status
About 6% fishermen were involved with crop farming besides of fish culture. Maximum of them were small fishermen. They were gross paddy only Boro season. The cultivated land were recorded that minimum 0.6 ha to 1.6 ha. The mean of cultivated areas was 0.98±0.54 and production 4278.33±1492.37. The average cultivation cost was 431666.67±33579.51. The mean gross income per ha was 59083.±45989.35.The data are given in the (Table 2).

Household income and expenditures
In my study areas it was found that the HH income of the fishermen was minimum 15,000BDT and maximum 1,67,000 BDT. The mean of the amount was 52520±42408.24 BDT (Table 3).  (Table 4).

Antibiotics
All of these antibiotics are effective against bacterial disease. These broad spectrum antibiotics were found to use by mixing with fish feed. The list of antibiotics is given in Table 5.

Disinfectants
Timsen, Polgard plus, Formalin, Bleaching powder, EDTA are found available in all the shops of Mahespur. The list of disinfectant is given in Table 6.

Oxygen supplier
Oxydizing agent, hydrogen peroxide are major active ingredients of oxygen supplier. Oxygen supplier used in the study area is shown in Table 7.

Growth promoter
There are several chemicals found in the chemical shops which were used as growth promoter as well as to raise production of fish (Table 8). Mainly these were used to protect fishes from bacterial, viral and other fungal diseases (Table 9).

Gas reducer
The present study identified a range of chemicals were used to reduce gases and to maintain the proper quality (Table 10).

Vitamin
Vitamin and minerals are important ingredients for growth of fish. Four vitamins with different trade names were found to use by the farmers (Table 11).

Enzyme
Only one type of enzyme was used by the farmers in fish feed named Biozyme. They use it at a dose of 25-50 gm/100 kg feed. Fish Tech provides the enzyme to the farmers.

Predator killer
Farmers used rotenone powder to remove predator fish. Rotenone with a brand name Acurte Gold is provided by a pharmaceutical company Samco was found in the study area. The recommended dose of Acurte Gold was 15 gm/decimal/1 ft depth.

Impact of various agrochemicals on fish health and diseases of fish in the study area
EUS was detected in Tilapia, Rui, Catla and Mrigal with 70% prevalence. Indian major carps found to be susceptible with Lerneasis having 80% prevalence. Pangus were also affected by tail rot and fin rot diseases with having 60% prevalence (Table 12).

Discussion
In the present study, it was noticed that among 50 fishermen of my study areas about 75% farmers having single ownership and 25% farmers having multiple ownership. About 82% fishermen had own land and the other farmer about 18% had culture others land. In my study areas the minimum and maximum value of 0.6ha and 12.04 ha. The result found in the present study differs from the result reported by Islam et al. (2014) and  who stated that land condition of fisherman. In this study, it is observed that 80% farmers follow polyculture system and 20% farmers followed monoculture system. The cultured fish species are Rui, Catla, Pangus, Tilapia, Koi, Sarputi and other carps. Most of the farm in our country followed polyculture and some farm followed monoculture system (Rahman, 2012;Haq et al., 2017;Shajib et al., 2017;Zafar et al., 2017). The cultured fishes were Rui, Catla, Pangus, Tilapia, Koi, Sarputi, common carp, Mrigal and Magur in Jamalpur and Sherpur district. Faruk et al. (2008) observed that the farmer interviewed were male with an average age of 37 years and the average family size 6; another few study in different place of Bangladesh showed the similar results (Islam et al., 2014;Asif et al., 2015;Hossain et al., 2015;Islam et al., 2015;Sharif et al., 2015;Sultana et al., 2015;Ali et al., 2016;Hossain et al., 2016;Vaumik et al., 2017;Razeim et al., 2017;Zaman et al., 2017;Islam et al., 2017;Habib, 2017 Adhikary et al., 2018a;Mondal et al., 2018a;Mondal et al., 2018b;Adhikary et al., 2018b). But in this study, the interviewed age 34 years old and their average. At present 24 animal health companies were seen to market at field level. In the study area different types of diseases like EUS, tail rot, fin rot, red spot, white spot and dropsy in different fish species mainly in Shing, Koi, Tilapia and Pangus were observed. A number of authors reported the similar condition in aquaculture of Bangladesh (DoF, 2002;Faruk et al., 2004;Asif et al., 2014;Shabuj et al., 2016;Yeasmin et al., 2016;Rahman et al., 2017;Neowajh et al., 2017;Biswas et al., 2018;Rahman et al., 2018). Most of the farmers of the selected areas used drugs and chemicals to control these types of diseases. It was observed that farmers of the study areas go good results in diseases treatment by applying single or combination of commercial aqua drugs and chemicals. In some cases after use of drugs they got about 95% recoveries within a short period of time. These result influence farmers to use more commercial aqua drugs and chemicals for diseases control and treatment. Normally in rural aquaculture farmers used traditional aqua drugs such as are lime, salt, urea, triple super phosphate (TSP), potassium permanganate, vitamins, antibiotics, (mainly oxytetracycline and chlorotetracycline), rotenone, phostoxin, sumithion, melathion and some hormones. It is also found that most of the farmers used chemicals and antibiotics (Chowdhury et al., 2015;Biswas et al., 2018;Adhikary et al., 2018). In the present study identified range of aqua chemicals and antibiotics marketed by different companies for using in various activities of aquaculture. Fish health management and diseases treatment were the major areas where farmers were seen to use a lot of such compounds. Other uses included growth promotion, improve water quality and as probiotics. Commonly found traditional chemicals in health management including are potassium permanganate, sumithion, melathion, formalin, bleaching powder, malachite green and methylene blue (Chowdhury et al., 2015;Rahman et al., 2017;Biswas et al., 2018;Rahman et al., 2018). Some previous studies also revealed the similar reports about the use of chemicals used in aquaculture of Bangladesh (Philips, 1996;Brown and Brooks, 2002;DoF;Faruk et al., 2004;Chowdhury et al., 2015;Biswas et al., 2018;Adhikary et al., 2018). The water quality management plays an important role in growth, development, reproduction, survival as well as feed consumption. For water quality management agriculture lime, Geotox, JV Zeolite, Mega Zeo Bio, Aquakleen and Biomin pond life have been used in the study area. Farmers use different types of aqua-medicine during pond preparation and water quality improvement. Anwar (2014) observed that for water quality management Geotox, JV Zeolite, Life, Aquakleen, Biomin, Aquabost are used. Chemicals like Geotox, JV Zeolite, Mega Zeo, Lime, BioAqua and Ames Zeolite are repeated by Monsur (2012) for pond preparation and water quality management. Dissolved oxygen is one of the most important factors of pond water for aquaculture practices. Farmers of the investigated areas use several chemicals to increase oxygen concentration in pond like Bio-ox, Oxygold, Oxylife, Oxymas, Oxyren, Oxyflow and Oxysos. Monsur (2012) observed that farmers used Oxyflow, Oxymas, Bio Care, Bio Ox, Oxy-gold and Oxy-A to improve dissolved oxygen level in Jamalpur and Sherpur regions. Faruk et al. (2008) found that the farmers of the Mymensingh region used Bio-ox, Gesonex, Oxymarine, Oxy plus, Oxymas, Oxymore and Bio care to increase dissolve oxygen. Rahman (2011) observed that aqua drugs like Oxyflow, Oxymas, Oxy plus, Bio Care, Pure Oxy, Oxy-Gold were used to increase dissolved oxygen, Oxidizing agent, Hydrogen Peroxide was the major active ingredients of such chemicals. Ali (2008) reported that Oxyflow and Oxymas were used to remove poisonous gases. Several chemicals with almost similar names were seen readily available in the chemical shops to use for increasing dissolved Oxygen (DO) in ponds. The propensity of using harmful gas controller is higher than any other medicines used by farmers in Maheshpur upazila. In the case 36% farmers showed their tendency to use, because most of the farmers had problems with harmful gases in their ponds (Uddin et al., 2014). Disinfectants are widely used in many spheres of aquaculture. As disinfectants, farmers use Timsen, Polgard plus, Formalin, bleaching Powder, EDTA and Eraprim vet in the study areas. Among them Timsen (disinfectant) is mostly available chemical in the chemical shops. Anwar (2014) (2018) observed that several branded antibiotics were found in the market; among them Oxysentin, Renamycine, Renamox and Orgamycine were being widely used. Sarkar et al. (2014) reported that Renamycine, Bactitab, Chlorstechlin, Cotrim-Vet, Orgacycline were being used antibiotics in coastal region of Bangladesh. Monsur (2014) also reported that Antibiotics should be used for bacterial diseases. From the research findings of Shamsuddin (2012), it was reported that most of the farmers used Renamycine at the rate of 100 mg/kg feed for 7 days for its high activity against bacterial diseases. The present study revealed that commercial aqua drugs have some positive impact on fish health management and diseases treatments at farmer's level. The present study identified arrange aqua chemicals and antibiotics market by different companies for using in various activities of aquaculture fish health management and disease treatment where the measure areas farmers sin to use a lot of such compounds. The present study also noticed a number of new product with various trade names in the market which is included zeolite, Geotox, mega geo, Aqua boost, Oxyflow, Biotuff quick oxygen, Orgavit, Aqua, Aqua Gold, Timsen, Efinol etc us video and various antibiotics and probiotics. The local animal feed and chemicals shops are the main source options compound from where farmers usually purchased these. The number of authors also reported similar condition in aquaculture of Bangladesh (Amin, 2000;Faruk et al. 2004). Growfast, Ossi-C, Nutrigrow are found in the study areas. Shamsuddin (2012) observed that farmers used Grow fast, Ossi-C, Silver mil and Revit C were used as a growth promoter in Fulbaria, Gouripur and Faridpur upazila of Mymenshing. Faruk et al. (2008) also reported that farmers used growth promoter such as Megavit Aqua, Aqua Boost, Aqua Savor and Vitamin premix, Grow fast, Vitamix and Grow max in Jhenaidah district. Farmers used as growth promoters Megavit Aqua, Aqua Boost, Aqua Savor, Vitamin premix, Grow fast, Nutricell Aqua, Rapid Aqua, Cevit Vet, Acimix super fish etc. In the study area only few people farmers used growth promoters increase diseases resistance power of fish because of high price. Various types of diseases are observed in Maheshpur Upazila. August, December, January and February are susceptible months of diseases outbreak in the study area. Monsur (2012) found that the affected month was August, November, January and February in Jamalpur and Sherpur district. However in February and March fish were also affected by diseases. In the study area some kinds of diseases were founded such as Epizotic Ulcerative Syndrome (EUS), skin diseases, gill damage, tail and fin rot. For highest stocking density tilapia and pangus were mostly affected by diseases in winter. In the study area different types of diseases like EUS, tail rot, fin rot, red spot, white spot and dropsy in different fish species mainly in Shing, Koi, Rui, Catla, Tilapia and Pangus were observed. A number of authors reported the similar condition in aquaculture of Bangladesh (Faruk et al. 2004). Most of the farmers of the selected areas used drugs and chemicals to control these types of diseases. It meant that's diseases problem was one of the major concern in aquaculture of the studied areas. Alam and Rashid (2014)  and silver carp in Jamalpur Sadar Upazila. Monsur (2012) observed that in Jamalpur and Sherpur district farmers used mainly Renamycine, Polgrad plus, Ossi-C, Timsen, Bactisal and Aquamycine for the fish disease treatment. Prasad et al. (1996) found that chloramphenicol and oxytetracycline would be effective drug in curing the EUS lesion tetracycline and streptomycine were found to be less effective in curing the ulcers. The present study identifies that, in case of rui, sarputi Renamycine 50 mg/kg body weight are effectively used in curing the EUS. Farmers use Renamycin with a result of 80-85% recovery to treat EUS in rui, sarputi, tilapia in the study area. But Rahman (2011) mentioned that EUS affected tilapia was treated with Renamycin, Polgard plus and Ossi C with 80-95% recovery form disease in Fulpur and Muktagacha. About 52% farmers used potassium permanganate, while 40% used lime, 11% used salt as a disease treatment in Bangladesh. According to the reports of Brown and Brooks (2002), a few Farmers used other treatments such as disinfectants, banana leaves, fertilizers, alum exchange. The present study identifies that tail rot and fin rot affected pungus are treated with tetracycline, methylene blue having 85% recovery. Rahman (2011) observed that Edwardsiellosis affected pangus were treated with renamycine, Timsen, Polgard plus, Ossi C in Fulpur and with Geolite and Timsen in Fulbaria having 80% recovery in both upazilas.

Conclusions
In conclusion, the present study demonstrated current status of chemicals and antibiotics using in aquatic animal health management and pointed out some problems of the use of chemicals by the farmers who is include lack of knowledge of the chemicals, doses and method of application of these chemicals. There are few alternatives to minimize the adverse effect of aquaculture chemicals simply use less of them. Other alternatives could be used as bioremediation and use of probiotics immune stimulants vaccination and alternative therapeutic. However policy maker researches and scientist should work together in addressing the issues of chemical used in aquaculture with a view to reduce the negative impacts.