Understanding the mechanisms that determine the critical habitat of commercial species is one of the significant challenges in marine science, particularly for species that inhabit the vast ocean worldwide. Previous investigations primarily focused on determining skipjack habitats without considering the feasible size for sustainable fisheries. To define habitat hotspots and movement patterns for decently sized skipjack tuna (≥50 cm) in Indonesia Fisheries Management Area (IFMA) 713, Indonesia, we examined the remote sensing of synoptic sea surface temperature (SST) and chlorophyll-a concentration (Chl-a) measurements with catch data from 2007 to 2016. A new skipjack tuna habitat model was developed based on the link between the key satellite-based environmental data and the best tuna fishery performance using a combination of generalized additive models (GAMs) and kernel density estimates. The findings reveal that feasible skipjack catch sizes were found in approximately 27% of total fishing grounds and were significantly captured in areas with a Chl-a of 0.15–0.28 mg m⁻³ and an SST of 29.5–31.0 °C, corresponding with an elevated skipjack habitat index (SHI). The habitat hotspots for the commercial skipjack were particularly produced by favorable Chl-a and SST, in association with Chl-a front and anticyclonic and cyclonic eddies, especially in October, which coincided with the highest skipjack catch per unit effort (CPUE). Skipjack distributions were mostly found within 10 km of favorable feeding habitats. They used the hotspot area as an indicator of their dynamics and movement pattern in the environment. The observed CPUEs cross-validated the predicted SHI values, suggesting that the model provided a reliable proxy for defining the potential habitats and the spatial movement of mature skipjack schools. Our findings have global significance for locating ecological hotspots, monitoring sustainable skipjack fisheries, and tracking skipjack migration, especially within the western tropical Pacific.

Symbiodiniaceae species is a dinoflagellate that plays a crucial role in maintaining the symbiotic mutualism of reef-building corals in the ocean. Reef-building corals, as hosts, provide the nutrition and habitat to endosymbiotic Symbiodiniaceae species and Symbiodiniaceae species transfer the fixed carbon to the corals for growth. Environmental stress is one of the factors impacting the physiology and metabolism of the corals-dinoflagellate association. The environmental stress triggers the metabolic changes in Symbiodiniaceae species resulting in an increase in the production of survival organelles related to storage components such as lipid droplets (LD). LDs are found as unique organelles, mainly composed of triacylglycerols surrounded by phospholipids embedded with some proteins. To date, it has been reported that investigation of lipid droplets significantly present in animals and plants led to the understanding that lipid droplets play a key role in lipid storage and transport. The major challenge of investigating endosymbiotic Symbiodiniaceae species lies in overcoming the strategies in isolating lesser lipid droplets present in its intercellular cells. Here, we review the most recent highlights of LD research in endosymbiotic Symbiodiniaceae species particularly focusing on LD biogenesis, mechanism, and major lipid droplet proteins. Moreover, to comprehend potential novel ways of energy storage in the symbiotic interaction between endosymbiotic Symbiodiniaceae species and its host, we also emphasize recent emerging environmental factors such as temperature, ocean acidification, and nutrient impacting the accumulation of lipid droplets in endosymbiotic Symbiodiniaceae species.

Hammerhead shark (Sphyrna lewini) population decline is a global problem experienced by various ocean basins worldwide, including Indramayu waters. As the regency known by its fishery barn that supplies 65% of captured fisheries in West Java, Indonesia, illegal fishing practices towards this protected species is inevitable. In 2017, 2869 tons of sharks were landed in Indramayu with the production value of IDR 44.01 billion, which hammerhead shark catch reaches 268 tons. This research aimed to observe the sustainability of hammerhead shark in Indramayu waters using a bio-economic model of Gordon Schaefer (GS) and Gompertz. The results showed the overfishing of hammerhead shark in Indramayu waters on actual conditions in 2012, 2014, 2015, 2016, 2017, and 2018, both in the GS and Gompertz models. The abundant number of hammerhead sharks started to deplete from 2015 to 2018, and the highest depletion was found in 2017, with a depletion value of 16 tons and depreciation value of IDR 164 million. The depletion rate suffered the most significant decline in 2011 to 2012 for all types of sharks, including hammerhead. The prohibition of consistent fishing and more pronounced law enforcement for hammered shark fishing are needed to maintain the sustainability of this resource.

Highlight Research First NR-SOB from Indramayu coast was successfully isolated and identified. Bactrerial characterization morphologically and biochemically, foster with in situ hybridization confirm the isolate was Thiobacillus denitrificans, and Arcobacter sp. Both isolate, Thiobacillus denitrificans and Arcobacter sp., were able to grow in sulphide rich environment in the presence of essential nutrient Thiobacillus denitrificans and Arcobacter sp. exhibit an outstanding sulphide oxidation ability up to 100% in the presence of nitrate. Abstract Crude oil production triggers the formation of hydrogen sulphide, also known as souring, which is extremely toxic and corrosive to the environment. It additionally give an adverse consequence to aquatic, terrestrial, and human existence. Studies of hydrogen sulphide reduction in sediments polluted by crude oil have been carried out recently to investigate the capability of indigenous Nitrate-Reducing Sulphide Oxidising Bacteria, hereinafter referred to as NR-SOB, as bioremediation agents. The experiments utilised hydrogen sulphide with 200 µM concentration combined with NO3 with different concentrations of 100 µM, 200 µM, and 300 µM. Measurements of the hydrogen sulfide concentrations were observed up to 48 hours within the experimental period. The SOB used in this study were taken from Balongan Bay at Indramayu coast using Nansen bottle to carry out water sample. The sulphide-oxidising ability of SOB was then evaluated at room temperature in control environment. Methylene blue method was applied to monitor the sulphide concentration. The results showed a complete removal of hydrogen sulphide concentrations in 48 hours accompanied with gradual drops of nitrate in all experiment series. Sulphide oxidation rate was detected to appear between 6.8 and 10.2 fmol/cell/hour. Measurements of cell abundance after 48 hours showed 6.2 x 105, 7.5 X 105, and 8.2 X 105 cell/ml from Experiments I, II, and III respectively. Using MSS selective medium, the bacteria were identified as Thiobacillus denitrificans and Arcobacter sp. Overall, the isolated NR-SOB from the coast of Balongan Bay, Indramayu proves to be a promising candidate for sulphide controls and mitigation.

Cadmium (Cd) is one of the heavy metals pollutants and its accumulation impacted the sustainability of marine organisms. The aim of current research was to isolate and identify the cadmium-reducing bacteria from contaminated coastal sediment in Karangsong port, Indramayu, Indonesia. The isolates were investigated for its potential to reduce cadmium showed the cadmium reduction drastically up to 50% at 6 hours treated under different cadmium concentration of 0,5, 1, and 1,5 ppm, respectively. Morphological characteristics were observed in most of isolates. Out of 8 isolates, two selected strains such as Karangsong Cd3 and Cd7 were identified by 16S rRNA sequencing as Pseudoalteromonas issachenkonii strain KMM 3549 (Acc. No. NR 025139.1) and Pseudoalteromonas tetraodonis GFC strain IAM 14160 (Acc. No. NR 041787.1), respectively. The cadmium resistance profile showed that the selected isolates were resistant to various concentration of cadmium (Cd). These results suggest that the Karangsong Cd 3 and Cd 7 could facilitate the new references of future microbial application for bioremediations efforts.