Abstract. Palupi M, Fitriadi R, Wijaya R, Raharjo P, Nurwahyuni R. 2021. Diversity of phytoplankton in the whiteleg (Litopenaeus vannamei) shrimp ponds in the south coastal area of ??Pangandaran, Indonesia. Biodiversitas 23: 118-124. Intensive shrimp farming in ponds is characterized by high stocking densities, complete feeding in quality and quantity, and good environmental control to produce the maximum quantity of shrimp in a fixed area. Phytoplankton is a bioindicator affecting the productivity of whiteleg shrimp in ponds. Currently, intensive shrimp farming activity is carried out on the south coast of Java, which utilizes sandy soil with a biofloc system, but the production has not been optimal. The objective of this study was to analyze the diversity and abundance of phytoplankton and water quality in the traditional and intensive whiteleg shrimp ponds in Pangandaran, West Java, to support sustainable pond management. The objective of the study was achieved by calculating the abundance, diversity index, evenness index and dominance index of planktons in intensive and traditional ponds. The study results showed that Chrysophyta division had the highest abundance and species number in both intensive and traditional ponds. The most abundant phytoplankton found in the intensive ponds was Halosphaera viridis (3143.88 ind/m3), and that in the traditional ponds was Rhizosolenia stolterfothi (1414.746 ind/m3). The phytoplankton diversity index (H') in the intensive ponds was 1.95 and that in the traditional ponds was 2.17. The dominance index value in the intensive ponds was 0.18 and in the traditional ponds 0.15. The abundance of phytoplankton is a limitation of the production success of whiteleg shrimp farming.

One of the limiting problem in fish larvae rearing is the availability of live feed such as zooplankton and phytoplankton. Spirulina platensis is a phytoplankton with important uses in fish larvae culture either as a live feed or an ingredient supplementation in the feed. However, its cultivation has high economic costs associated with the growth medium. One of the alternative medium that potentially reduce costs and environmentally friendly is tofu wastewater. The purpose of this research is to evaluate the combination of tofu wastewater with urea for the cultivation of S. platensis. We investigated the growth of S. platensis in tofu wastewater containing various concentrations of urea: 0 g (control), 10 g, 20 g, 30 g, or 40 g urea added to 3 L diluted (2:1) tofu wastewater. The S. platensis productivity parameters were measured are population density, specific growth rate, and doubling time. The population density growth was significantly different, while the specific growth rate and doubling time were not significantly different for the various urea concentrations. The optimum growth was observed with 10 g urea per 3 L medium. This combination of tofu wastewater with urea could be a cost-effective medium for the cultivation of S. platensis.

Abstract. Samudra SR, Fitriadi R, Baedowi M, Sari LK. 2022. Pollution level of Banjaran River, Banyumas District, Indonesia: A study based on the Saprobic Index of periphytic microalgae. Biodiversitas 23: 1527-1534. The saprobic index of periphytic microalgae can be used to determine the level of water pollution based on the number and composition of species. Banjaran River is one of the rivers in the Banyumas District, Central Java, Indonesia, which is widely used by the local people for daily activities. The increase of domestic and agricultural activities in the river triggers an increase in the pollutants input into the river. This study aims to determine the status of the waters in the midstream of Banjaran River by using the periphytic microalgae saprobic index as a bioindicator of water quality. Purposive sampling method was used in this study by establishing four stations and five replications at each station. The result showed that the abundance of periphytic microalgae ranged from 7,547-8,733 cells/cm2; the diversity index ranged from 1.64-2.07 (moderately polluted waters); the dominance index ranged from 0.21-0.26 (no particular species of periphytic microalgae dominating the four stations); and saprobic index value of Banjaran River ranged from 1.00 to 1.03 which indicates that Banjaran River belongs to ?-meso/oligo saprobic water. In other words, it was water with a light pollution level. An action to reduce organic pollution is necessary, one of which is by reducing the people's activities such as washing and disposing of household waste into the river so that the condition of Banjaran River can be maintained properly and reduce pollution in its subsequent river flows.

Kerapu Macan (Epinephelus fuscoguttatus) memiliki habitat asli di perairan laut dan merupakan ikan karang. Penelitian ini dilaksanakan di unit usaha kelola benih unggul Desa Klatakan, Pecaron Kabupaten Situbondo Jawa Timur. Populasi penelitian ini menggunakan 3 bak pemeliharaan larva dan 20 bak kolam pakan alami. Teknik pengambilan sampel dengan cara langsung dilapangan. Hasil penelitian menunjukkan bahwa Larva D2-D30 kerapu macan diberi pakan jenis rotifer  dengan kepadatan  3-10 individu/ml, Nauplius Artemia salina diberikan saat larva D 15 hingga D35 selanjutnya udang rebon diberikan pada saat larva D26-50.  Dosis pemberian VIT C 1%. Dosis pemberian baik untuk rotifer dan naplius Artemia salina adalah 0,6 ppt. Nilai HR (Hatching rate) telur mencapai 80%. Tingkat kematian tertinggi pada hari D3 sebanyak 50 %.

Perkembangan budidaya laut dari tahun ketahun terjadi peningkatan, usaha perikanan skala rumah tangga banyak berkembang di daerah pesisir Kabupaten Situbondo dikelola oleh pembudidaya ikan hanya atas dasar milik mereka sendiri modal dan pengalaman, tetapi tanpa mempertimbangkan keuangan aspek kelayakan bisnis dan konservasi lahan buidaya. Tujuan untuk mengetahui kelayakan usaha, volume dan nilai produksi budidaya kerapu cantang. Data primer dianalisis menggunakan analisis deskriptif dan analisis kelayakan bisnis melalui pendekatan kriteria investasi. Hasil penelitian menunjukkan bahwa Hasil yang didapatkan adalah  BEP unit: 265.506.000 ekor, BEP harga : 42.657.325 / tahun, B/C Ratio:  1,30 dan Pay back period 2,1.