Length-weight relationships and condition factors of the three dominant species of marine fishes caught by traditional beach trawl in Ulelhee Bay, Banda Aceh City, Indonesia

Abstract

The objective of the present study was to examine the length-weight relationships and condition factors of snapper Lutjanus russellii , ponyfish Aurigequula fasciata and white-spotted spinefoot Siganus canaliculatus harvested from Ulelhee Bay, Banda Aceh City, Indonesia. These species are the predominant fishes caught by traditional beach trawl in Ulelhee Bay, Banda Aceh City, Indonesia. The sampling was conducted for three months from April to June 2015 at one-week interval. A total of 900 fish samples (300 individuals for each species) were measured for the total length and body weight. The length-weight relationships were calculated using Linear Allometric Model (LAM), while the relative weights (Wr) and Fulton’s condition (K) factors were calculated to assess the condition of the fish samples. The results showed that the b value of 3.04 in snapper indicates isometric growth pattern, while ponyfish and white-spotted spinefoot fish had the b values of 1.41 and 1.75, respectively, and these species display an allometric growth pattern. The average Fulton’s condition factor (K) of snapper was 3.01 for male and 2.49 for female; female ponyfish has the K value of 2.92 and 2.92 for male. In addition, the average K value of white-spotted spinefoot was 2.61 and 2.59 for female and male, respectively. The relative weight condition factor ranges from 58.73 to 166.09 for snapper, from 70.55 to 129.65 for ponyfish, and from 71.63 to 133.53 for white-spotted spinefoot. In general, the relative weight condition factors tendedto be 100. It is concluded that snapper has isometric growth pattern, while ponyfish and white-spotted spinefoot display the negative allometric growth pattern. The condition factors are in excellent condition and indicate a balance of prey and predator.