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Sardinella fish (Sardinella lemuru) is a species of important pelagic fish from the family of Clupeidae found in Bali Strait. The dynamic condition of Bali Strait makes it fertile which is identical with plankton blooming. The objective of this research was to understand the potential of saxitoxin in sardinella fish because of dinoflagellates consumption in Bali Strait. The research was conducted in Southeast Monsoon (June - August 2015) and Northwest Monsoon (December 2015 – February 2016). The method used was in situ plankton sampling, counting and ELISA test to determine the level of saxitoxin in the fish. Hydro-oceanographic parameters measured were temperatures, salinity, DO (dissolved oxygen), pH level, phosphate level, nitrate level and transparency. They showed average optimum value for phytoplankton growth especially during Southeast Monsoon which its temperature lower and the nutrients (phosphate nitrate) higher than the Northwest Monsoon. This condition caused high richness of phytoplankton in the water and followed with dinoflagellates richness so they accumulated in sardinella fish. It was supported by the analysis of the fish gastric which showed positive correlation between dinoflagellates richness in the water and the fish gastric. ELISA test also showed that saxitoxin level of fish caught in Southeast Monsoon was higher than the one caught in Northwest Monsoon even though the level of saxitoxin was still in the safe range (less than 80 μg STXeq. per 100 g) but the danger of saxitoxin accumulation should be watched out for.

Balinese Sardinella (Sardinella lemuru) is the main commodity in Indonesia. Despite, more research show that lemuru got the overfishing condition. In East Java region, likely Bali Strait, Southern-East Java water, and Madura Strait are the region which the most production of lemuru catch. So it needs identification stock of Sardinella lemuru on the third fisheries management east java sub-region, as it to be used as a reference to managing the sustainability of the catch sardinella lemuru for the future. Research carried out in January to May 2016 with the methods is the sample of random sampling on three different locations water representing Madura Strait, Bali Strait, and southern-East Java water. The each sample implemented were in four times during a period of months old different. Every the sample researchers get as 50-200 tail. Sardinella lemuru in accordance with the season fish. The sample which has been obtained taken to the laboratory of Marine Science University of Brawijaya to data take. The analysis used in this research was Truss morphometric and Factor analysis of the condition allometric. Based on the results of the analysis in the Madura Strait, Bali Strait, and Southern-East Java water are having a distinction of morphometric character amount 44 % with the character being very affected is PAL_FL, DFB_HL , PVL_FL, UPCL_FL, OD_HL, and PPL_FL. Around 64 % of the whole morphometric character that is 14 characters. Next, if it is seen from Allometric condition in the third these waters having b value different from each aquatic and after B-test that lemuru in the three the waters might otherwise dissimilar stock so management of Sardinella lemuru in the three waters should have been undertaken in separated.

Understanding the impact of Indian Ocean Dipole (IOD) on fishery around Indonesia is important as the fishery resources are small compared to the demand. In this study, we analyzed the effect of positive and negative phases of IOD on chlorophyll-a concentration and the catch of Sardinella lemuru in the Bali Strait. Data are based on field surveys in the Bali Strait during the positive and negative phase of IOD and Sea Surface Temperature (SST) and Sea Surface Chlorophyll (SSC) obtained from the analysis of satellite images. The results suggest that SSC concentration in the strait significantly correlates with the positive and negative phase of IOD, possibly through a change of upwelling and downwelling there. It is suggested that the change of phytoplankton biomass due to positive IOD would result in an increase of Sardinella lemuru in the Bali Strait. This research has direct implications as important information for the government in planning lemuru fisheries management in the Bali Strait based on oceanographic studies and climate phenomena.

The complete mitochondrial genome of Sardinella lemuru was sequenced using PCR amplification and primer walking sequence method. The complete mitochondrial genome of S. lemuru was 16,616 bp and contained 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes, and one control region (D-loop). The overall base composition was A 25.04%, C 29.36%, G 20.40%, T 25.20%. In this study, the gene arrangement was consistent with other Sardinella mitochondrial genomes. Additionally, the phylogenetic relationships of 23 Clupeoidei species based on the complete genome was analyzed, and the result showed that S. lemuru firstly clustered with other two Sardinella species, S. albella and S. maderensis. These results would be useful for the investigation of phylogenetic relationship, taxonomic classification and phylogeography of the Clupeoidei.