Plastic is one of the main pollutant sources that are difficult to decompose and then carried into the ocean and fragmented into smaller parts (microplastics) due to UV radiation and water currents. Their small size means that microplastics are often ingested by aquatic organisms, such as fish. This research aimed to determine the presence, abundance, and types of microplastics in the digestive tract of four dominant fishes landed at Lengkong Fish Auction Point, Cilacap, Central Java, i.e. threadfin ( Eleutheronema tetradactylum), mackerel ( Rastrelliger sp.), threadfin bream ( Nemipterus japonicus), and hairtail ( Trichiurus lepturus). We found microplastics in the digestive tract of four selected fishes with a frequency of occurrence of 100%. The concentration of microplastics in fish digestive tracts is relatively high, with a value range of 12 ±2.86 to 28.33 ±8.11 particles∙ind.-1. Microplastics were found in films, fibres, fragments, and granule shape types with various colours: brown, purple, blue, black, green, transparent, and yellow. The polymers found were polystyrene (PS), nylon, acrylonitrile butadiene styrene (ABS), polyurethane (PU), polypropylene (PP), high-density polyethylene (HDPE), and low-density polyethylene (LDPE). The present study provides baseline data for microplastics contamination in commercial fish species landed at Lengkong Fish Auction Point, Cilacap, Central Java, Indonesia. The fact that we discovered PU, the most harmful polymer, piques our attention.

To date, exploration of Gracilaria and Gelidiella’s bioactive compounds has been conducted using conventional methods that require a long time, high costs, and significant effort. Currently, metabolomic profiling and molecular networking have emerged as methods of exploring bioactive compounds. This study aimed to perform bioactive compound profiling through a metabolomic LC-HRMS-based and molecular networking approach in Gelidiella acerosa, Gracilaria arcuata, and Gracilaria verrucosa. All chromatograms and MS/MS spectra obtained for three crude extracts were digitally converted into an mzXML file using MSConvert, submitted to the Global Natural Product Social (GNPS), and visualized in Cytoscape 3.9.1. In total, nine dereplicated compounds were identified: 11-Deoxyprostaglandin (m/z 324.214), Diacylglyceryl trimethylhomoserines (DGTS) (m/z 684.575), Glycochenodeoxy acid (m/z 448.369), Lysophosphatidylcholine (m/z 522.350), Diacylglyceryl trimethylhomoserines (DGTS) (m/z 656.557), Pheophorbide A (m/z 593.266), Pyropheophorbide A (m/z 593.266), (2R,3R)-2-(3,4-dihydroxyphenyl)-3,5,7-trihydroxy-2,3-dihydro-4H-chromen-4-one (m/z 303.15), and Polyporic acid (m/z 293.156). These compounds are typically classified as fatty acids, lipids, terpenoids, alkaloids, shikimates, and phenylpropanoids. The molecular networking and metabolite clustering showed an interesting pattern where some compounds were produced only by one species, some by two species, and some by all three. These compounds may have pharmaceutical potential based on their chemical properties and reported activities.

Gracilaria edulis, a red seaweed that is widely known as an agar-producing seaweed, has a unique biosynthetic pathway for producing bioactive compounds. However, most of the bioactive compounds of this species have not explored yet. The environmental conditions as well as the extraction method might influence the bioactive compound production. Hence, this study aimed to explore untargeted liquid chromatography–high resolution mass spectrometry (LCHRMS)-based metabolomics profiling of G. edulis (Gracilariales, Rhodophyta) from three different beaches along the southern part of the Special Region of Yogyakarta (Java Island, Indonesia), which has different environmental characteristics. We also observed the effect of extraction solvent on metabolomic profiling of G. edulis extract using three different solvents with the different polarity. Metabolomic profiling was performed using an LC-HRMS instrument and analyzed using the Global Natural Product Social Molecular Networking (GNPS) database. The results revealed differences in the metabolomic profiles of G. edulis’s extracts based on coastal location and solvent. G. edulis from Kukup Beach exhibited the highest metabolomic diversity (277 nodes), followed by G. edulis from Sepanjang Beach (268) and G. edulis from Krakal Beach (204). Among the solvents, n-hexane was the most effective, extracting 311 nodes, followed by methanol (293) and ethyl acetate (197). Nine tentatively dereplicated compounds were found, i.e., pumilacidine C, pumilacidine E, lichenysin, cholesterol, AC1L1X1Z, sarmentoside B, 7-dehydrocholesterol, pheophytin A and porphyra-334. Some dereplicated compounds were found in a specific area. For example, lichenysin and pumilacidin compounds were produced by G. edulis from Sepanjang Beach, while cholesterol and AC1L1X1Z were found in from G. edulis extract, which were collected from Sepanjang and Kukup Beaches, and 7-dehydrocholesterol and sarmentoside B compounds from all beach locations, while pheophytin A and porphyra-334 from Krakal Beach. Further research is needed to obtain pure compounds that have the potential to be antibacterial, as well as antioxidant, anti-inflammatory, and photoprotective compounds.

Pangandaran waters is one of productive fishing ground for Indonesian fisheries. One of potential catch in this area is red snapper. Red snapper (Lutjanus campechanus) is a type of demersal fish. This species can live in shallow waters to deep seas. Growth measurement is carried out as an anticipation on the presence of overfishing which causes red snapper stocks to decline. Hence, current field work focused on the growth characteristics and factor conditions of red snapper which landed in PPI Cikidang Pangandaran west Java. Present study may provide information related on fish species production. The survey and observation methods were used to collect the data in February 2021. The sampling location was carried out at the PPI Cikidang, Pangandaran. The data of weight and length of red snapper landed at PPI Cikidang were recorded and analyzed descriptively. The results revealed that growth of red snapper landed at the PPI Cikidang was categorized as negative allometric with b < 3, at 1.92. The condition factor has an average of 1.29 which means that the fish are classified as fat or not flat. Â Keywords: Growth Characteristics; Condition Factor; Red Snapper; Lutjanus campechanus; PPI Cikidang.

Nannochloropsis oculata is a type of single-celled or eukaryotic phytoplankton belonging to the class Eustigmatophyceae. This type of microalgae is widely used as natural food for rotifers and fish larvae because it has a high nutritional content. Given this role, many species of Nannochloropsis oculata are cultivated by culture. The success of microalgae culture is influenced by growth factors such as light intensity, CO₂, temperature, and nutrition. However, in the process problems often arise regarding the unstable growth of Nannochloropsis oculata. This is usually caused by factors that affect growth, such as light that is not optimal. Based on these problems, it is necessary to conduct research that aims to determine the growth rate of Nannochloropsis oculata with different irradiation treatments. The research method used was an experimental method with 4 treatments i.e., A (24L : 0D), B (12L : 12D), C (18L : 6D), and D (6L : 18D). The results showed that different light exposure period on the density of Nannochloropsis oculata microalgae had no significant effect on their growth rate. Even though the results of statistical tests of photoperiod administration did not affect the production of Nannochloropsis oculata microalgae cell density, the treatment with the dark phase resulted in better growth.