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.

Age, growth and maturity of frigate tuna (Auxis thazard Lacepède, 1800) in the Southeastern Brazilian coast

“…4). The lowest value (ɸ' = 4.8) was associated with the lower L ∞ (354 mm) estimated for the Indonesian population (Lelono and Bintoro, 2019).…”

“…Growth rate was similar and particularly high for maximum age in the Indian Ocean, where data was estimated using length frequency analysis (Kasim, 2002;Abdussamad et al, 2005;Ghosh et al, 2010;Mudumala et al, 2018). The exception is the most recent report by Lelono and Bintoro (2019), where the growth rate was 0.58 year À1 for frigate tuna caught in two landing sites off the Indonesian coast. Taiwanese estimates were also lower (k = 0.50-0.52) and similar to one another, despite using length frequency analysis and vertebrae, respectively (Lu et al, 1991;Tao et al, 2012).…”

“…Maximum age in our study was of 4 years, similar to recent observations in India (Mudumala et al, 2018); however, most studies in India have reported maximum ages of 3 years (Kasim, 2002;Abdussamad et al, 2005;Ghosh et al, 2010). Additionally, for Taiwan, Indonesia and Iran, the frigate tuna attains up to 5 years (Tao et al, 2012;Lelono and Bintoro, 2019;Darvishi et al, 2020).…”

“…The frigate tuna (Auxis thazard, Lacepède, 1800) is a small, epipelagic, cosmopolitan scombrid found in tropical and subtropical oceans, around islands and occupying continental shelves (Collette and Nauen, 1983). It reaches sizes of approximately 500 mm and a maximum age of 4 years in India (Abdussamad et al, 2005;Lelono and Bintoro, 2019). In Iran, Indonesia and Taiwan ages of 5 years have been estimated, however, A. thazard attains lower maximum sizes (Tao et al, 2012;Darvishi et al, 2020).…”

Size Distribution, Length-Weight Relationship, and Catch per Unit Effort of Frigate Tuna, Auxis thazard (Lacepède, 1800) in Tawi-Tawi Waters, Southern Philippines, Caught Using Multiple Handline

“…In Taiwan Strait, the dominant age of frigate tuna was two years (Tao et al, 2012). Numerous studies conducted in different parts of the world oceans revealed that this tuna species showed positive allometric growth (Ghosh et al, 2012;Tampubolon et al, 2016;Mariyasingarayan et al, 2018;Mudumala et al, 2018;Petukhova, 2019;Lelono & Bintoro, 2019;Herath et al, 2019).…”