Highlight Research:The bullet tuna (Auxis rochei) was identified and analysed.The length at first maturity (Lm) of bullet tuna (Auxis rochei) was analyzedThe eligibility status of bullet tuna (Auxis rochei) has been analyzed and estimatedThe LWR curve can be used to estimate age groups of fish compared to the sigmoid curveThe CF cannot be automatically used to estimate fish worth selling AbstractThe bullet tuna (Auxis rochei), BLT or tongkol lisong (Indonesian) is a species of neritic tuna which is one of the target fish for small scale fishers. The problem of bullet tuna fisheries was that it has reached overexploitation and the immature bullet tuna are still caught. This study aimed to assess the population dynamics of the BLT and its size composition caught by small scale fishers in the Indian Ocean, West Nusa Tenggara area was carried out in Bangko-Bangko (West Lombok), Cemplung Beach (South Sumbawa) and Tanjung Luar Fishing Port (East Lombok) between July 2019 and June 2020. The data was derived from the measurement and weighing results of 1,217 BLT collected from the respective collector traders at each sampling location. The growth pattern of BLT was isometric () which meant the ideal body shape (mesomorph) and length at first maturity (FLm) was 31.11 cm. The length-weight relationship curve showed that BLT was in an immature age group (adolescent fish). Meanwhile, the composition of BLT is worth selling (Condition Factor > 1.00), fit for catch (FLc / FLm > 1.00) and worthy of maturity (FLc > FLm), respectively 99.92%, 0.82% and 0.00%. The BLT fish composition indicates that the stocks of resources and populations do not support current sustainable fisheries management.

HighlightBullet tuna (Auxis rochei Risso 1810) has been identified (measured, weighed) and analyzed.The resource status of bullet tuna has been estimated based on body shape and age group.LWR curve is implemented to describe and express the age group of bullet tuna (immature, adult/mature, old)This study has resulted the composition and ratio of bullet tuna that is suitable to be caught, fit for consumption and worthy of maturationAbstractBullet tuna (Auxis rochei Risso 1810) or tongkol lisong (Indonesian) is important for human consumption and health as well as an income source for fishers and coastal communities. Its utilization problems are over exploitation, catch domination by immature groups, and the threatened stock security of the bullet tuna (BLT). This research aimed to determine the status of the prospective parent of bullet tuna caught in the Lesser Sunda region, particularly from the Alas Strait to the Indian Ocean, West Nusa Tenggara (WNT). Meanwhile, the data were collected from July to September 2020 (2nd transitional season) at the Tanjung Luar Fishing Port, East Lombok and a dependent survey method was adopted with sampling, interview, observation, and documentation techniques. Fork length and body weight data were used to estimate the length and weight relationship, growth pattern, condition factor, fish age group, and catch worth. The primary and secondary data were processed quantitatively using several equations. The growth pattern of bullet tuna was minor allometric (b = 2.875), worth selling (K > 1.00), and the majority was adult fish or mature group. The LWR model is . This condition indicates the bullet tuna is worth catching  and worth spawning, so that it is eligible to be a potential broodstock candidate to support a sustainable management of BLT fisheries. Furthermore, fishers have applied the code of conduct for responsible fisheries (CCRF) in supporting the sustainable development goals.