Length-Weight Ratio and Condition Factor of Endemic Fish Oryzias nigrimas (Kottelat, 1990) in Poso Lake, Central Sulawesi

Abstract

This research aimed to evaluate the length-weight relationship (LWR) and condition factor of the endemic fish Oryzias nigrimas in Lake Poso and took place from May 2017 until April 2018. A total of 645 O. nigrimas samples were analysed (137 males and 508 females). The length-weight equation was 1.55 × 106 L2.346 for males and W = 3.95 × 106 L2.107 for females. The LWR coefficient b was b = 2.346 for males and b = 2.107 for females (combined value 2.155) which means that b < 3, indicating O. nigrimas is a fish with an allometric negative growth pattern. The condition factor ranged from 0.945-1.091 for males and 0.940-1.107 for females. Overall, the condition factor (Kn) ranged from 0.940 - 1.091, indicating that the sampled fish could be considered in a normal condition. Kn appeared to be related to reproduction with the average Kn value of both male and female fish, being highest in September and February during peak spawning seasons.