Length-weight Relationship and Study using RAPD Technique to Determine the Genetic Variation of Yellow Catfish (Mystus nemurus, Valenciennes 1840) in Nong Han lake, Sakon Nakhon Province, Thailand

Background: Yellow catfish, one of Southeast Asia’s most economically significant fish, is found in natural water sources in Thailand. Research on genetic diversity is essential for effective aquatic species management. The purpose was to assess the length-weight relationship (LWR) and genetic diversity of yellow catfish (Mystus nemurus) from Nong Han Lake, Thailand. Methods: 330 samples were collected from ten subpopulations: Ban Tha Rae (n = 31), Don Ang (n = 30), Wat Phon Bok (n = 30), Don Sakhan (n = 32), Don Sao Aey (n = 30), Don Sawan (n = 40), Nguyen Don (n = 32), Lum Nam Phung (n = 40) and Ban Tha Sala (n = 35). Surasawadi floodgate (n = 30). The LWR and feeding intensity were described by the equation W = aTLb and the condition factor (KF) was calculated as KF = 100 W/TLb and RAPD technique was used to evaluate the populations. Result: The results showed b and KF values ranged from 2.7841-3.6942 and (KF) values from 0.1706-2.0943. 102 DNA bands were identified from RAPD with sizes ranging from 200 to 2,500 bp. Polymorphic loci were found in 71.57% to 98.04%. Nei’s gene diversity ranged from 0.24 to 0.36. The genetic distance between reproducible bands of amplified DNA fragments varied from 200 to 2,500 bp. The UPGMA dendrogram of the RAPD-PCR patterns revealed two groups of genetic relationships. The average genetic distance across all samples ranged from 0.020 to 0.245.