Study On Length–Weight Relationship and Relative Condition Factor of Skipjack Tuna Katsuwonus pelamis (Linnaeus, 1758) Landed at Veraval Fishing Harbour, Northwest Coast of India

Abstract

The present study was carried out during the period from March 2025 to February 2026 at Veraval, Gujarat, India to investigate the length–weight relationship and relative condition factor of Skipjack tuna (Katsuwonus pelamis) landed. A total of 300 Skipjack tuna samples were collected, out of which 171 were males, and 129 were females. The total length of the sampled fish ranged from 41.0–71.5 cm, while body weight varied from 969–7340 g. The total length and body weight of each specimen were recorded and analyzed using the standard length–weight relationship equation, W=aL^b, where W represented body weight, L represented total length, a was the intercept, and b was the regression coefficient. The length-weight relation was established for both genders individually. In males, the length-weight relation was W=0.0027×L^3.4546 (R²=0.938), while in females, it was W=0.0023×L^3.4975 (R²=0.939). On pooling the values of both genders, the length-weight relation became W=0.0026×L^3.4649 (R²=0.9391). The regression coefficient (b) was greater than 3, indicating positive allometric growth, suggesting that fish gained weight at a faster rate than length as they increased in size. The weighted mean relative condition factor (K_n) was 0.9999±0.0883 in males and 1.0026±0.0712 in females, indicating a generally stable and healthy condition in both sexes. The findings of the present study provide baseline information on the growth pattern and condition status of K. pelamis from the northwest Arabian sea.