Carbon emission due to excess fuel consumption by the trawlers of Thoothukudi, Southeast Coast of India.

Single-day trawling is commercially practiced along Thoothukudi coast, involving a total of 275 trawlers of varying length range operated from Thoothukudi fishing harbour (8°47’N, 78°9.5’E). The trawlers can be classified in three categories: vessels with overall length (OAL) of 40–50′ (Type 1), OAL 50–60′ (Type 2) and OAL above 60′ (Type 3). Trawlers with OAL of 45′, 55′ and 65′ were selected for the study. Irrespective of the type of vessel, the power required for towing the net was found to be unnecessarily high. The excess power wasted due to faulty trawl designs in Type-1, Type-2 and Type-2 vessels was 55, 87 and 133 hp, respectively. While trawling with optimal trawl design would contribute only 28.67% of the brake horse power (BHP) of the Type 3 vessels, the existing design of trawl used in this type of vessels contributed as much as 50.83% of the BHP. The Type-1, Type-2 and Type-3 trawlers were found to operate with excess fuel consumption at the rate of 103, 212 and 418 L of diesel per cruise, respectively. Based on the annual fuel consumption, true total annual CO2emission was estimated as 458 tons. The study revealed that the total fuel consumption can be reduced by 40% by optimizing the trawl design and reducing the free-running speed, free-running duration and trawling speed. Further, vessels with an OAL of 60′ and above may be permitted for multi-day fishing in distant waters after suitably limiting the number of fishing trips/month in order to minimize the fuel loss through free running. [ABSTRACT FROM AUTHOR]