Journal of the Marine Biological Association of India

Biometry, length-weight relation and condition factor of Indian squid, Uroteuthis duvaucelii (Cephalopoda: Loliginidae), in the trawling grounds of the southeastern coast of India

Volume 67 Issue 1

R. John Peter, A. John Chembian and K. Silambarasan

doi:10.6024/jmbai.2025.67.1.2554-10

Abstract

This study evaluated the length-weight relationship, linear morphometric traits, and condition factors (Kn) of 1,206 individuals of the Indian squid Uroteuthis duvaucelii, collected during a Fishery Survey of India exploratory fishery resources survey along the southeastern coast of India. Regression analysis revealed negative allometric growth between dorsal mantle length (DML) and total weight (TWt), with b values of 1.86 in males, 2.606 in females, and 2.003 for pooled sexes. For DML and mantle weight (MWt), the b values were 2.061 males, 2.41 females, and 2.102 pooled sexes. ANCOVA results indicated significant variations in sex-based differences (P < 0.01) in regression slopes. Linear morphometric relationships showed negative allometric growth for most of the morphometric characters, except DML-TL and MCA-MCF, which exhibited positive allometric growth. Sex wise analysis revealed that females grow faster at smaller sizes, while males attain larger maximum sizes. Condition factor (Kn) analysis revealed values ranging from 0.702 to 1.369 in males and 0.681 to 1.447 in females. The higher variability observed in females was likely due to energy allocation for reproduction. Peak Kn values were recorded at 51-70 mm DML for males and 71-90 mm DML for females, indicating optimal phases for somatic growth. In contrast, lower Kn values at larger sizes reflected the depletion of energy reserves due to reproductive activities.

Keywords

Size variations, allometric, condition factor, Uroteuthis duvaucelii, Bay of Bengal

Date : 11-06-2025