Impacts of Pangasius aquaculture on land use patterns in Mymensingh district of Bangladesh

Pangasius catfish, Pangasianodoan hypophthalmus farming has been evolved to a shape of commercial enterprise over the last two decades in north-central part of Bangladesh, particularly in Mymensingh area but there is a lack of quantitative and qualitative data on the impacts of it on land use pattern. This study was conducted using multiple methodological tools including participatory rural appraisal (PRA) tools and mainly questionnaire based farm survey to assess the impacts of Pangasius farming on land use from February to September, 2009. The mean farm size (ha), water area (ha) and dyke area (ha) was 1.36±1.25, 1.06±1.31 and 0.30±0.27, respectively. The Pangasius productivity was significantly and positively correlated with water area and dyke area. Around 10.1% area of the study area was converted to Pangasius farm which was previously used as rice-field. Farmers expanded their farm area by taking leased lands which contributed to 56.47% of total farm area and the lease value of Pangasius pond was doubled compared to agriculture land. Around 48% area of dyke were used to produce agriculture crops and the production was 71.01% lower but profit margin was 76.58% higher than normal land. The discharging wastewater of Pangasius pond also increased rice productivity in adjacent agriculture farm by 10% and additionally reduced fertilizer and irrigation cost by 30% and 40%, respectively. Keyword: Pangasius aquaculture, impact on land use pattern, Bangladesh Introduction Aquaculture and fisheries together contributes about 5% of total GDP of the country’s economy and 6% of the total annual export earning. Contribution of aquaculture and fisheries for animal protein accounting for 63% of the total national intake is still dominating although considerable development was occurred in livestock and poultry sector [Department of Fisheries (DoF), 2009]. Bangladesh's total fish production for the year 2007-2008 was above 2.56 million ton achieving sixth rank among the major aquaculture producing countries in the world (FAO, 2009). Out of total fish production, aquaculture contributes 39% and remaining 42% and 19% was from inland capture fisheries and marine fisheries, respectively [Department of Fisheries (DoF), 2009] indicating aquaculture is the fastest growing food producing sector in Bangladesh. Regionally, inland aquaculture production is dominated in the north-central region, i.e. the greater Mymensingh district, where Pangasius catfish, Pangasianodoan hypophthalmus farming was started commercially in 1994 by a private fish farm named Al Falah, Mymensingh (Ali, 2009). The estimated total Pangasius production in Bangladesh was about 3, 00,000 tonnes in the year 2008 (Edward and Hossain, 2010 and Munir, 2009). Sarker (2000) reported that amongst exotic fish species, Pangasius is one of the best aquaculture species in Bangladesh due to its ease of culture, high market demand and well suited to the weather condition its propagation and culture. In recent years, Pangasius has become one of the most popular commercial culturable species due to its high yield, higher response to external feeding, and availability of Pangasius seeds to meet up the farmer’s demand. Over the last 15 years, Pangasius aquaculture evolved to a shape of commercial enterprise having long backward and forward linkages providing livelihoods for a wide range of stakeholders (Haque, 2009). Almost all of the produces are consumed domestically proving year round supply of animal nutrition to low and medium income people in both rural and urban areas. Total fish production of the country during the last two decades has increased about three times, from 895,935 tonnes in 1990-1991 to 2563,296 tonnes in 2007-2008 [Department of Fisheries (DoF), 2009]. Such expansion has huge positive impacts as discussed above, however a large concern is that aquaculture has some negative environmental impacts. Expansion of aquaculture requires conversion of land related to crop fields, wetlands, seasonal waterbodies, mangrove forests, and other terrestrial and aquatic ecosystems. Land is the basic natural resource that provides habitat and sustenance for living organisms, as well as being a major focus of economic and livelihood activities (PDOICZMP, 2004). The population is increasing and the land is being converted from productive purposes, such as crop 170 Impact of Pangasius aquaculture on land use cultivation, to other uses such as housing, roads and urban development, and this trend is expected to continue. This is because there is no such a national policy for any systematic land use strategy that was already implemented by other Asian countries (e.g. Vietnam, Indonesia, etc.) consolidating and distributing the land resources to the appropriate users through the control of the government towards sustainable land use (Griffin et al., 2002). Collectively increasing pressure of aquaculture, agriculture and other non-agricultural activities on land use made the scientists and policy makers concerned about sustainability of food production for future generation. In terms of inland aquaculture, particularly of Pangasius aquaculture in Bangladesh, as there is no any legal aquaculture legislation in place for land use, consequences could be the same as the of shrimp farming in coastal areas (Primavera, 2006). Therefore, the overall environmental impact due to land use for Pangasius farming became an important issue deserves to be addressed thoroughly. Considering the above fact, the present research work was carried out to assess the impacts of Pangasius aquaculture on land use patterns in selected areas in Bangladesh. Materials and Methods This study was conducted in Dhanikhola of Trishal upazila under Mymensingh district (Fig. 1) from February to September, 2009. Ali (2010) reported that Pangasius farming first started by private enterprise in Trishal which was very close of the study village. The authors also reported that the number of Pangasius farms higher in Dhanikhola compared to other areas of Trishal upazila. This village was a typical Pangasius producing area in terms of early development, having large number of farms, higher production level and better access to the markets. There were 135 farms in the study area and out of which, 60 farms were randomly sampled for this study. The information of this study was collected based on questionnaire interview and in addition, key informant interview and focus group discussion. Draft questionnaire were tested with few farmers before preparing final questionnaire. During the testing period, attention was given to include any new information and based on the feedback the final questionnaire was prepared. Fig. 1. Map of Trishal upazila showing the study area