Population dynamics and feeding habits of Euthynnus affinis, Auxis thazard, and Auxis rochei in South Coast of East Java waters

Abstract

Little tuna landed there are three types: Euthynnus affinis, Auxis thazard, Auxis rochei. The analysis shows the condition of the resource indicates the condition Over Exploited. Length and weight relationship tuna (Auxis thazard) total positive allometric Length of first caught fish (Lc) of 27.08 cm, The length at first maturity (Lm) 28.39 cm Lt = 35.40 {1 - e -0.58(t + 0.26)}, total mortality (Z) = 4.08 per year, Fishing mortality (F) = 2.91 per year, natural mortality (M) = 1.17 per year, with the Exploitation rate (E) = 0.71 per year which, if E> 0.5 is overfishing. The relationship between length and weight of Tuna (Euthynnus affinis) was unsexed W = 0.1078 L 3.48. The value of Lc and Lm were 37.51 cm, 38.43 cm, and 40.17 cm respectively. Von Bertalanffy growth Lt = 72.50 {1 - e -0.11(t +0.27)} equation of this study was. The rate of total mortality (Z), natural (M), and catch (F) were respectively 0.56, 1.74 and 0.01. The peak season tuna catch in PPN Prigi was occurred in September (515.865%) with the low season occurred in January (1.244%). As for UPT PP Muncar, the peak season cob arrest took place in March (316.315%) with famine in February (6,651%). Little Tuna food was consist of 7 groups, namely: small fish, shrimp, Ascomycota, Chloromonadophyta, Chyanophyta, Chrysophyta, and Chlorophyta.