This study examines the biometric parameters of Auxis thazard, a commercially significant neritic tuna species in Sri Lanka, after primary and secondary data analyses. In secondary data analysis, data following the year 2017 were obtained from the Department of Fisheries and Aquatic Resources for a comparative study of Western, Southern and Eastern coasts. The Length-Weight Relationships (LWR) for Auxis thazard in West, South and East coasts were W= 0.0012TL^3.6586, W = 0.0026TL^3.4846 and W = 0.0147TL^2.951. The pooled regression coefficient (‘b’) values indicated positive allometric growth in West and South, and isometric growth in East. The condition factor showed relatively healthy conditions in fish for West and South and poor condition for East. The gillnets reported 98% of catches in West and ringnets reported. 68% and 67% of catches in South and East respectively. The primary data analysis was conducted in the West coast from November 2021 to February 2022. The LWR was W= 0.0114TL^3.0366 indicating isometric growth and fish were relatively healthy. Shrimps were the most preferred prey item at each stomach fullness level. The percentages below 29.5 (length at first maturity reports by FishBase) included 18.8, 39.2 and 34.0 for West, South and East suggesting continuous fish landing monitoring.