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

Cilj studije bio je proučiti dužinsko maseni odnos te kondicijske faktore Lutjanus russellii, Aurigequula fasciata i Siganus canaliculatus ulovljenih u Ulehlee zaljevu, u gradu Banda Aceh, u Indoneziji. To su prevladavajuće riblje vrste, ulovljene tradicionalnim koćarenjem s kopna u Ulehlee zaljevu, u gradu Banda Aceh, u Indoneziji. Uzorkovanje je provođeno kroz period od tri mjeseca, od travnja do lipnja 2015. godine u intervalima od tjedan dana. Izmjerene su totalna dužina i masa na ukupno 900 uzoraka riba (300 individua iz svake navedene vrste). Dužinsko maseni odnos izračunat je pomoću linearnog alometrijskog modela (LAM), dok su relativna težina (Wr) i Fultonov koeficijent (K) izračunati kako bi se ocjenilo stanje uzoraka riba. Rezultati su pokazali da b vrijednost (3.04) kod Lutjanus russellii ukazuje na izometričan rast, dok je vrijednost b za Aurigequula fasciata i Siganus canaliculatus iznosila 1.41 i 1.75 te su vrste pokazale alometrijski rast. Prosječan Fultonov koeficijent (K) Lutjanus russellii iznosio je 3.01 kod mužjaka i 2.49 kod ženki. Kod oba spola Aurigequula fasciata K je iznosio 2.92. Uz to, prosječna vrijednost K Siganus canaliculatus iznosila je 2.61 kod ženki i 2.59 kod mužjaka. Općenito, faktori stanja relativne težine obično iznose 100. Zaključeno je da Lutjanus russellii ima izometričan obrazac rasta, dok Aurigequula fasciata i Siganus canaliculatus pokazuju negativan alometrijski uzorak rasta. Kondicijski faktori su u izvrsnom stanju te ukazuju na ravnotežu plijena i predatora.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 whitespotted 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