The use of seaweed for nutrient absorption in aquaculture effluent has gained significant attention. This study investigated the effects of density and surface area-to-volume (SA:V) ratios of three seaweeds: Caulerpa lentillifera, Ulva rigida, and Gracilaria fisheri, on nutrient uptake in fish culture effluent. Nutrients absorption of NO2-, NO3-, NH4+, and PO43- was measured at algal densities of 10, 20, 30, 40, and 50 g·L-1 every hour over a 24 h period. Optimal absorption of NO2-, NO3- and PO43- by all three seaweeds occurred at a density of 30 g·L-1 within 24 h; with maximum removal efficiencies for C. lentillifera reaching 86.03%, 74.08%, and 100%, respectively; for U. rigida, 87.33%, 76.51%, and 100%, and for G. fisheri, 87.82%, 73.77%, and 100%, respectively. At 40 g·L-1, both C. lentillifera and U. rigida achieved 100% NH4+ removal within 20 h, while G. fisheri showed 100% NH4+ removal within 18 h at a density of 20 g·L-1. In this study, U. rigida exhibited the highest SA:V ratio (12.99±0.06 cm2:cm3), surpassing that of C. lentillifera (4.48±0.33 cm2:cm3) and G. fisheri (4.07±0.17 cm2:cm3). The SA:V ratio had a positive correlation with total nitrogen reduction, Pnet and Fv/Fm. Due to its high SA:V ratio and sheet like morphology, U. rigida was the most effective at nutrient absorption compared to the siphonous-like C. lentillifera and cylindrical, bush-like G. fisheri. These results highlight the influence of photosynthetic response on nutrient absorption with varying algal densities and SA:V ratios, identifying an optimum density of 30 g·L-1 for green algae and 40 g·L-1 for red algae.

One of the functional groups of herbivorous reef fish is parrotfish from the family Scaridae. These fish have been categorized as excavators and scrapers, which enables them to support coral resilience by controlling the algae growth. Unfortunately, some species of parrotfish have been reported as targeted fish and faced uncontrolled fishing. This study aims to estimate the targeted parrotfish population in different locations to discern variations of fish in Sulawesi, and to provide information on the relationship between the fish and their habitat conditions. The study was focused on three species from Buton, Kendari, and Makassar, Scarus dimidiatus, Scarus ghobban, and Scarus niger using UVC and UPT methods to collect the data. The estimated population of fish was reported to be in good condition in Buton, but not in other locations. Moreover, S. ghobban showed a good estimated population among locations, while S. niger in Makassar indicated uncontrolled fishing conditions. The fish were found to prefer locations with more complex benthic substrate compositions, with Buton being the most populated location compared to Makassar and Kendari. Furthermore, fleshy seaweed was correlated with the biomass of S. ghobban. The sea surface temperature (SST) was related to chlorophyll-a and indicated a connection to benthic substrate consumed by the fish, which contributed to the abundance and occurrence of parrotfish in Sulawesi

Cancer, as a chronic illness, is characterized by a high mortality rate. Current cancer treatments, such as chemotherapy, have significant drawbacks, including long half-lives and numerous adverse effects. Medications derived from natural products offer a safer alternative as supplementary treatments. One such natural product is marine macroalgae, commonly known as seaweed. Secondary metabolites from marine macroalgae exhibit a range of potential biological activities, including anticancer properties. The objective of this study was to determine whether the methanolic extract of Halimeda tuna from the Acehnese coast possesses potential anticancer properties. Halimeda tuna was extracted using the cold maceration process, which involved immersion in methanol solvent for 24 h. The MTT assay was used to assess the cytotoxicity of crude H. tuna extract against HeLa cervical cancer cells. GC-MS testing and phytochemical analysis were conducted to identify the compounds present in the extract. The yield of H. tuna extract was 0.168±0.025%. The MTT assay determined the IC50 value of H. tuna against HeLa cells to be 126.460±46.167 µg·mL-¹. Phytochemical analysis revealed the presence of flavonoids, steroids, and alkaloids, while GC-MS analysis identified fatty acids, steroids, and flavonoids in the extract. These compounds may contribute to the anticancer effects observed, consistent with an IC50 value that indicates moderate cytotoxicity. Further research is required to explore the potential of H. tuna extract as an alternative anticancer agent.

Currently, marine crustacean aquaculture production is high in Asia; however, mud spiny lobster (Panulirus polyphagus) production has been slow. Therefore, gaining more knowledge about mud spiny lobster farming and cultivation management is imperative. This study aimed to bridge this knowledge gap by investigating farmers' activities and environmental factors related to farming, focusing on their impact on mud spiny lobster growth and utilization. The study was conducted in 3 locations, namely Ban Chong Lad, Ban Khao Thong, and Ao Nao areas in southern Thailand from April 2022 to February 2023. The study revealed that three spiny lobster species were cultured in these areas. Panulirus ornatus had the highest percentage, followed by P. polyphagus, with Panulirus vesicolor being the least common. The supply chain started with wild seed procurement from collectors, with juveniles cultured in sea cages for 3–5 months for P. polyphagus or over a year for P. ornatus and P. vesicolor. Most lobsters were sold live to Thai and foreign tourists. The growth monitoring of P. polyphagus revealed a significant impact of density on growth. Lobsters in Ao Nao, which were stocked at lower density, had higher body weight and growth rate compared to those in Ban Khao Thong and Ban Chong Lad. Notably, regular supplementation with fresh mussels seemed to promote better growth in Ao Nao. Meanwhile, water quality parameters (salinity, pH, dissolved oxygen, and temperature) did not appear to affect the growth of this lobster species across areas. This information provides valuable insights for optimizing mud spiny lobster cultivation practices in sea cages.

Plankton play a crucial role in pelagic ecosystems, serving as a primary food source in marine food webs and influencing nutrient cycling. Hydroacoustic methods are effective for detecting targets such as plankton by generating backscatter values, which indicate their distribution. This approach provides insights into their horizontal and vertical distribution. This research aimed to map and analyze the spatial and temporal distribution of plankton volume backscattering strength (SV) values ​​using hydroacoustic methods, and to examine the relationship between these SV values ​​and environmental parameters in the waters around Tunda Island, Banten. Data collection included oceanographic measurements: temperature, salinity, DO, pH, currents and water clarity, as well as acoustic data. Oceanographic data were gathered from 16 sampling points at the water surface around Tunda Island. The relationship between oceanographic parameters and acoustic data was analyzed using Principal Component Analysis (PCA). The study found that temperatures around Tunda Island ranged from 28 to 30.2 °C, salinity from 30.3 to 33.5‰, pH from 8.1 to 8.4, DO from 6.39 to 7.67 mg·L-1, water clarity from 9.57 to 34.36%, and currents from 0.13 to 0.69 m·s-1. The SV for horizontal plankton distribution ranged from -82.04 to -76.06 dB, while vertical distribution ranged from -82.04 to -75.07 dB. PCA analysis showed that the relationship between plankton distribution and aquatic parameters accounted for 57.2% of the cumulative variance, with each parameter making either a positive or negative contribution. This research provides baseline data on plankton abundance and environmental conditions in Tunda Island’s waters, highlighting the use of hydroacoustic methods for detecting fine-scale distribution patterns in relation to ecological variables. The findings contribute valuable insights into plankton ecology in areas impacted by anthropogenic activity, supporting future ecological monitoring, fisheries management, and resource conservation efforts.

Cenderawasih Bay is one of the territorial waters of Indonesia with high fishery potential. In 2022, the Indonesian Goverment revealed that the bay's small pelagic fishery potential reached 135,140 t, yet the utilization rate remains at only 0.3, indicating underutilization. This shows the necessity of estimating fish distribution in the bay to maximize the use of small pelagic fisheries resources. The hydroacoustic method, known for its extensive survey coverage and minimal environmental impact, can be employed to estimate the distribution of small pelagic fish. Therfore, this research aims to investigate the distribution of acoustic parameters of small pelagic fish using a split beam echosounder, specifically the SIMRAD EY-60, to obtain fish SV value and distribution data. SV (Scattering Volume) values were coverted to TS (Target Strength) values and projected onto a spatial distribution map. The distribution of fish exhibited a varied range of values, with the highest SV value ranging from -59.7 to -57.4 dB and the highest TS values ranging from -59.4 to -46.7 dB. Fish distribution was more concentrated in areas with warmer temperatures and dispersed evenly across different salinity ranges, with a higher concentration of fish detected in areas with elevated chlorophyll levels.