• B.Geetha
• K.Ganesh
• Malathi

Gulf of Mannar is an endowed with a rich variety of marine organisms because its biosphere includes ecosystems of coral reefs, rocky shores, estuaries, mangrove forests and sea grass beds. Tamil Nadu is situated between 8” 5’ and 13” 35’ north and 76’ 15’ and 80’ 20’ along the South East coast of India bordering the Bay of Bengal. Tuna is a sleek and streamlined fish, adapted for speed. It has two closely spaced dorsal fins on its back and is a high protein fish that belongs to the tribe Thunnini, a subgrouping of the Scombridae (mackerel) family. As a result of overfishing, some tuna species are threatened with extinction. Sampling was done every fortnight in the above landing centres. The specimens were collected from the catches of trawl net, bottom set gill nets and hook and lines on an average of fifty boats per sampling day. The data collected were station-wise for calculation of various biodiversity indices. The weight and length of the fish species were measured by measuring materials. The present study was carried out for a period of six months from October 2019 to March 2020. Euthynnus affinis and Katsuwomus pelamis available in high. From the 4 species of tuna monitored by the IUCN, 24.32 % were reported to be Near Threatened, 21.73 % Vulnerable and 7.52 % Endangered. This means that approximately 56 % of the total tuna species are facing major conservation threats.

Tuna, Diversity indices, Conservation, Gears.

"Studies on the Present Status of Diversity indices, Biology and Conservation methods of Tuna fish (Family: Scombridae) in Threshpuram fish landing along the Southeast Coast at Thoothukudi District, Tamil Nadu", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.7, Issue 6, page no.945-951, June-2020, Available :http://www.jetir.org/papers/JETIR2006132.pdf

"Studies on the Present Status of Diversity indices, Biology and Conservation methods of Tuna fish (Family: Scombridae) in Threshpuram fish landing along the Southeast Coast at Thoothukudi District, Tamil Nadu", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.7, Issue 6, page no. pp945-951, June-2020, Available at : http://www.jetir.org/papers/JETIR2006132.pdf