Squid (Loligo sp.) is an economically important fishery resource in the Karimunjawa Islands, Central Java, Indonesia, yet information on its length-weight relationship and population dynamics were limited. This study analyzed the length-frequency distribution, length-weight relationship, growth, mortality, and exploitation rate of squid catch in Karimunjawa Island. A total of 431 squid individuals were sampled from fish-trading sites over seven days each month from December 2024 to January 2025. Mantle length and body weight were measured, and growth parameters were estimated using the ELEFAN I method in FiSAT II based on the von Bertalanffy growth model. Mantle length ranged from 22.9 to 48.3 cm, with the 25.1-28.0 cm size class accounting for 35% of the sample. The length-weight relationship was W = 1.38L^1.6937 (R² = 0.6041), with a growth coefficient (b) of 1.6937, indicating negative allometric growth. The estimated asymptotic length (L∞) was 49.8 cm, with a growth coefficient (K) of 0.58 year⁻¹. Natural mortality (M), total mortality (Z), and fishing mortality (F) were 1.12, 1.17, and 0.05 year⁻¹, respectively, resulting in a low exploitation rate (E) of 0.04, well below the optimum level of 0.5. These findings indicate that the squid resource in Karimunjawa waters was not overexploited during the study period. Continued monitoring and precautionary management, including control of fishing effort and minimum catch-size regulations, are recommended to support sustainable utilisation.
