Length-Weight Relationships of Lutjanus decussatus as Conservation Target Species in Anambas Islands Marine Protected Area, Indonesia

Abstract

Lutjanus decussatus, commonly known as the checkered snapper or sadang fish (locally), is a key coral reef species in the Anambas Islands Marine Protected Area (MPA) and serves as a conservation target and indicator of reef health. This study analyzes the length-weight relationship and growth patterns of sadang fish within the MPA. Purposive sampling was conducted from February to October 2023, with 537 samples collected (175 males, 362 females). Male fish reached a total length (TL) of 29 cm and a weight of 345 g, while females attained a TL of 30 cm and a weight of 410 g. The R² values were 0.93 for males and 0.90 for females. The length-weight regression exponent b was 2.762 for males and 2.748 for females, indicating negative allometric growth (b < 3), where length increases faster than weight. This is the first study to examine the length- weight relationship of L. decussatus in the Anambas Islands MPA, providing essential biological and fisheries data to inform species management strategies.