BIODIVERSITAS ISSN: 1412-033X Volume 24, Number 6, June 2023 E-ISSN: 2085-4722 Pages: 3528-3535 DOI: 10.13057/biodiv/d240651 Sustainable economic analysis and length weight relationship of Bullet Tuna (Auxis rochei) fishery in east area of Bali Strait, Indonesia GATUT BINTORO 1, , DARMAWAN O. SUTJIPTO 1 , TRI D. LELONO 1 , BAMBANG SEMEDI 2 , AIDA SARTIMBUL 2 , MITA T. WAHYUNI 1 1 Program of Fisheries Resource Utilization, Faculty of Fisheries and Marine Science, Universitas Brawijaya. Jl. Veteran, Malang 65145, East Java, Indonesia. Tel.: +62-341-553512, Fax.: +62-341-557837,  email: gbintoro@ub.ac.id 2 Program of Marine Science, Faculty of Fisheries and Marine Science, Universitas Brawijaya. Jl. Veteran, Malang 65145, East Java, Indonesia Manuscript received: 9 May 2023. Revision accepted: 26 June 2023. Abstract. Bintoro G, Sutjipto DO, Lelono TD, Semedi B, Sartimbul A, Wahyuni MT. 2023. Sustainable economic analysis and length weight relationship of Bullet Tuna (Auxis rochei) fishery in east area of Bali Strait, Indonesia. Biodiversitas 24: 3528-3535. Bullet tuna (Auxis rochei) is a small pelagic fish with an important economic value and is mainly caught by fishermen in the east area of Bali Strait, Indonesia. The high market demand for this fish has increased fishing efforts to achieve maximum catch, and this uncontrolled fishing activity will threaten its sustainability and economic potential. This study was conducted to determine stock status both biologically and economically. The length-weight relationship was calculated by measuring the length and weight of 1,200 samples of fish landed in the Pengambengan Archipelago Fishing Port (AFP) in Jembrana Bali Province from February to March 2020. The calculation of maximum sustainable yield (MSY), maximum economic yield (MEY), and equilibrium of open access (OA) were done by using secondary catch data from 2008 to 2019. Gordon Schaefer’s model analysis found that the values of YMSY and fMSY were 3,314 tonnes year -1 and 3,503 trips year -1 , respectively. While the values of YMEY and fMEY were 3,160 tonnes year -1 and 2,750 trips year -1 , respectively, which gave a maximum profit of about 1.4 billion USD year -1 . In addition, the equilibrium of OA would be achieved when the fishing effort reaches 5,500 trips year -1 and the amount of catch reaches 2,237 tons year -1 . The growth pattern of the bullet tuna was isometric, which indicates that the bullet tuna in the east area of Bali Strait has a proportional body shape. The utilization status of bullet tuna (A. rochei) is over-exploited. Keywords: Maximum economic yield, maximum sustainable yield, pelagic fish, total revenue, utilization status INTRODUCTION Bali Strait is a stretch of waters with an area of about 2,500 km 2 between the Java and Bali islands. The Bali Strait connects the Indian Ocean and the Java Sea, providing plenty of fishery resources. These fisheries resources are dominated by pelagic fish, which has characteristic of pelagic shoaling species such as Bali sardinella (Sardinela lemuru) (Simbolon et al. 2017), scads (Decapterus spp.), and bullet tuna (Auxis rochei). Species of pelagic fish have a high propensity to migrate. Purse seines are the primary fishing gear in most fishing activities because these fishing gears can catch pelagic schooling fish effectively. Fishing activities around the east area of the Bali Strait are concentrated in Jembrana waters, with a fishing port located in Jembrana Regency, namely Pengambengan Archipelago Fishing Port (AFP), with bullet tuna as one of the potential fishery resources (Harlyan et al. 2022). Bullet tuna is a fishery resource with a high economic value which is a targeted species to be exploited, and the main catch landed in the Pengambengan AFP. The bullet tuna landed at the Pengambengan AFP in 2017 was 1,997 tons. This catch increased to 5,542 tonnes in 2018 (Pengambengan 2018). The nutritional content of bullet tuna includes a high percentage of moisture (74.3%), high protein (22%), high distribution of lipids within its body (3.1%), glycogen (0.3%), and minerals (1.2%) (Mudumala et al. 2017). However, the exploitation of bullet tuna has increased annually due to the high demand for this fish resource. Consequently, it may affect the continued presence of bullet tuna resources in the Bali Straits waters. The utilization of marine resources has a general nature, namely open access, where fishery resources can be exploited freely as long as profits can still be obtained. The availability of fish stocks in the waters will be significantly impacted by exploitative behavior contrary to the rules, excessive, and typically destructive. (Kekenusa et al. 2015). Analysis of the level of resource exploitation is one of the efforts to control the level of exploitation. Ineffective and destructive resource management will disrupt the sustainability of resources. Endeavors to control management sustainability can be handled by combining economic and biological aspects to produce estimates of fishery stocks and water conditions (Anna et al. 2017). Several studies indicate that pursuing economic goals in fisheries plays an important role in overfishing and the decline of marine ecosystems. This statement is supported by several major causes, including private-beneficial decisions made by individual fishers, which can lead to overfishing and lower profits, and short-term profit motives in managed fisheries, leading to unilateral political pressure to establish unsustainable harvest levels (Asche et al. 2018).