Economic analysis of P.monodon post larvae by-catch in Indian Sundarbans: An impasse between livelihood and conservation

The livelihood of most of the fishers in Indian Sundarbans is dependent on Penaeus monodon post larvae fishing. These post larvae collectors are socially backward lacking economic security. The activity of collecting Penaeus monodon post larvae for rearing in aquaculture, destroy other aquatic species. Many other juveniles of shellfish and fin fish were destroyed in the process of collection of Penaeus monodon post larvae. The removal of juveniles before they reach maturity disturbs the ecological chain by hampering breeding processes and may cause extinction of some fish species in the long run. The present study is an attempt to estimate the economic value of juveniles destroyed in the collection of (Penaeus monodon) post larvae. In total 32 species were identified in P.monodon the post larval by-catch. The economic loss is assessed based on estimating biomass by taking a length-weight relationship from published literature. Further, the paper illustrates how does a profit enterprise is linked with natural resource exploitation. The paper explores government policy and nature conservation issues for social justice and effective conservation.In conclusion, suggestions are given to reduce the burden of livelihood on natural resources to the extent of exploitation and to strengthen institution and policy-making considering socio-ecological vulnerabilities of the area.


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The Sundarban Biosphere Reserve is the world's largest mangrove forest and the delta of

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The methodology is discussed in the following heads  at an interval of 30-40 minutes, and the whole content is emptied in an aluminum container. The net is 112 lifted and adjusted automatically to the rise in water level. After the segregation is over, the leftover 113 fin fish and shell fishes were dumped or left in due course of time. Samples were collected from 2 nets 114 belonging to commercial P.monodon post larvae collectors at the sampling site. When the catch was 115 low, the entire sample is taken, but when the catch was high, a suitable sub sample was analyzed, and 116 the total number was obtained by increasing samples proportionately (figure 3). Samples collected 117 were then segregated according to species or group. Most of the species were identified at field level.

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Apart from taxonomical identification, some fish species were identified based on their local names.

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Length and weight of 10 samples of individual species were taken and genera wise aggregate weights 120 of fish were recorded. Unidentified fish species or fish species having some doubt during field level 121 identification were preserved in 5 percent formalin and labelled adequately for laboratory analysis.  The methodology for calculating biomass is based on the assumption that if the juveniles are left to grow up to a certain period and were caught later after attaining maturity (known as weight at first maturity) how much it will cost. It is also based on the assumption that biomass of juveniles increase will increase positively with their growth rate and negatively with their mortality rates[36] where, W is the estimated weight (gms) of i th fish species at first maturity, a is constant value and b is length (cm) at maturity of i th species. The average sample () was calculated by FAO, 1984 where, Y ij is the total catch of i th species, and n is no. of sampling per day 132 133 In certain month, the quantity of catch is much higher, and it is not possible to count and calculate the whole catch. Therefore a representative sample was taken, and the proportion of each species was calculated in the sample. The proportion of each species in total catch was calculated using the following formula: The quantity of biomass corresponding to juveniles was calculated to juveniles landed by the following formula: The survival rate, S, was estimated by modifyingRicker [37] method as, where M= natural mortality coefficient.

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The results are discussed in the following heads   The monthly wise loss of juveniles due to P.monodon by-catch is given in figure 4. The maximum 161 loss is recorded in the month of July with 115 kg per day and minimum loss of 2.64 kg is recorded in 162 March. The lean period is observed from the month of October to February. The biomass estimated 163 for the discarded juveniles as by-catch during P.monodon post larvae collection is given in Table 3.

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The estimated biomass is completely based on the juveniles' fish/ discarded fish quantity landed and 165 the mortality rate and weight of fish at first maturity. The highest quantity is estimated for Acetes Peripthalamus species, Glosogobius girius, Nandus nandus. Since these species have high fecund rate,its 181 juvenile fetches more price in the market compared to market price when sold at first maturity.

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The loss of juveniles due to post larvae collection is a matter of concern for sociologist,  4. Chowdhury, A.; Naz, A.; Maiti, S.K. Health risk assessment of 'tiger prawn seed'collectors exposed to