Explicit traces of longliners to sustainably harness marine fisheries: Evidence from fuzzy VIKOR approach

Sustainable and judicious exploitation of marine resources has been a highly debated topic in recent times, in particular relation to the growing environmental impacts such as diminishing fish stock, changes in climate leading to uncertain economic profitability in marine capture fisheries. Developing countries like India suffer the most due to the multi-species nature of the fisheries and its biodiversity. Indeed, there is a dire need for an ideal fishing gear to sustainably reap the marine fish without damaging the ecosystem. This study from Palk Bay, India, throws light on the economic aspects of major fishing methods and its compatibility towards sustainable harvests. Results demonstrate that the economic net profit US$ 40452 year–1 was higher for trawler than those of longliner (US$ 39738 year–1) and gillnetter (US$ 19645 year–1) with no significant difference observed between trawler and longliner (P>0.05). But the profit margin (20%) was low for trawler compared to longliner (25%); because; of the total gross revenue, the fuel cost was 10% higher for trawler compared to longliner. Profit of the fishing fleet relies heavily on the input of fossil fuel which also significantly affects the environment. The energy efficiency in terms of fuel use intensity (FUI) was estimated to be 3.5 and 2.7 fold greater for longliner and gillnetter, respectively compared to trawler. The lowest of 0.520 tons of CO2 was emitted per ton of fish caught in a longliner whilst the same, amounted to 0.684 tons of CO2 for gillnetter and 1.823 tons CO2 for trawler. The fuzzy VIKOR index computed using different performance indicators of fishing fleets pointed long liner to be ideal.  Result of the scenario analysis advocates that 40% existing trawler replacement aids to save fuel combustion of 121.33 million litre year–1 that could prevent emission of 9.5 million tons of CO2 per annum during fishing which in turn would largely serve to reduce the climate change effect. Ground truthing for the same has been done for the conversion of trawler to longliner. The average catch amounted to 10 to 12 tons per trip (15 days per trip) generating a net profit of US$ 8065 to 11290 for the same.