HighlightThe highest composition was Bacillariophyceae class and lowest was Cyanophyceae.Phytoplankton community abundance in waters is tightly related with nutrient content such as phosphate, nitrate, silicate, and other nutrients.Relation between abundance, biomass, and nutrients in Mamberamo river had the same pattern throughout February, May, and August in 2016.High biomass in an area related positively with phytoplankton abundance in its area.AbstractMemberamo River in Papua Province, that is a place of livelihood for the surrounding population, has a high biodiversity. This study aimed to provide information about the condition of the waters in the Mamberamo River by using biological and chemical parameters, namely community and phytoplankton biomass and chlorophyll-a content. The method used in determining the location was purposive random sampling based on differences in microhabitat that conducted in February, March, August, and October 2016. Phytoplankton observations were carried out through the method of sweeping Sediment Rafter (SR), and phytoplankton biomass obtained from chlorophyll-a. The results of this study showed three classes of phytoplankton were found, namely Bacillariophyceae, Chlorophyceae, and Cyanophyceae. The highest class of abundance was found in the river such as Bacillariophycea Chlorophyceae, and Cyanophyceae respectively. The chlorophyll-a concentration of phytoplankton biomass ranged from 2.01-548.73 mg/l and equation obtained from regression analysis between abundance and chlorophyll-a content was y = 1.2206 x – 0.7702 with a coefficient of determination r = 0.68. It could be concluded that the high phytoplankton biomass had a positive relationship with the chlorophyll-a content and the condition of the waters of the Mamberamo River is still categorized as good with good water fertility

Inland waters provide huge fish resources and are exploited as food security by local people. The method used in this study was intended to evaluate the performance of the management in terms of the Ecosystem Approach to Fisheries Management (EAFM). The study was conducted in five districts in Indonesia, namely Cilacap, Sukabumi, Kampar, Kapuas, and South Barito, from February to August 2019. The primary data were gathered through observation and interviews with fishers, local government, indigenous community, NGO, and other stakeholders. The secondary data were collected from previous studies. The EAFM domains are presented in a questionnaire that refers to the technical guidelines for assessing fisheries management indicators with an ecosystem approach. The indicators are grouped into seven domains in rating the current management of inland fisheries. The Likert score is used to measure respondents' attitudes to a particular question or statement. The score criteria used in examining fishery management by EAFM tools-based ordinal 1,2,3, designed to measure opinion or perception from the questionnaires. The results showed that the economy and stakeholder domain were poor categories, indicated by a red flag. Nevertheless, the management conditions, especially for the managed fish resources domain, were classified as good.

Mahseer is commonly used as a premium consumption fish with exceptional price, however, these species have encountered dwindle in distribution and abudance. The objective of this study was to investigate and to compare aspects of the interspatial variability of Western Sumatra component growth of mahseer between Manna River and Tarusan River. Mahseer samples were collected from the Manna River, Bengkulu Province and Tarusan River, West Sumatra Province. Monthly sampling was carried out over a period of February to October 2012 in Manna River and February to July 2012 in Tarusan River for detailed growth study. A total of 295 mahseer samples were collected from five sampling sites in Manna River and 495 mahseer samples were collected from three sampling sites in Tarusan River. The results show the ge group population estimation of T. Tambroides from Manna River and Tarusan River based on the analysis of length-frequencies using the Bhattacharya method, resulted in two different age groups. The theoretical growth curve for length from Manna River, the values are L¥ = 50,45 cm, K = 1,90 yr-1, t0 = -0,07 yr-1 and F  = 3,684, and for weight, the values are W¥ = 1395,49 gr, K = 0,71 yr-1, t0 = -0,078 yr-1 and F  = 6,148. The parameters of the von Bertalanffy growth curve in length from Tarusan River were L¥ = 31,34 cm, K = 1,70 yr-1, t0 = -0,09 yr-1 and F  = 3,21 and W¥ = 634,86 gr, K = 0,48 yr-1, t0 = -0,147 yr-1 and F  = 5,282 in weight.  The length-weight relationship estimated for Manna River was W = 0,000007TL3,086 for females (R2 = 0,9545, N = 91) and W = 0,0037TL1,882 for males. While for Tarusan River, length-weight relationship estimated was = 0,00003TL2,839. Mahseer from Manna River population has better growth parameters than those at Tarusan  River.

Semah fish is a fish that has high economic value. The population of this fish has decreased drastically. Based on the studies that have been carried out, the problem of decreasing the population of Semah Fish raises management efforts that can ensure the sustainability of fish resources. The method used is direct observation in the field, fisherman's catch, and fish identification is carried out in molecular or DNA sequences. This review was conducted in 2022 on research that has been carried out in Sungai Manna, South Bengkulu Regency, and in Batang Tarusan, Pesisir Selatan Regency in 2012. The aim is to review and review the results of research that has been carried out related to the characteristics of fish management strategies and Semah Fish. . The results of the review on the study showed that the Semah Fish that lived in the Semangka River (Lampung Province), Manna River (Bengkulu Province), and Batang Tarusan River (West Sumatra Province) were identified as Tor tambroides species and constituted an integrated population or reproductive unit in this area. each of these rivers. In addition, it was found that several management efforts were carried out to maintain fish habitat, recommending that the Semah Fish conservation area in the Manna River can be determined, especially the Negara Kaya – Timun Island, the limitations of the size of fish that can be caught, which is more than 245 mm standard for the Manna River. , is greater than 206.6 mm for Batang Tarusan River, and regulates the fishing season in April and September.

The potential for fish production is very important as a necessary material for WPP PD in making policies. Estimation of fishery production potential is adjusted to aquatic ecosystem. The method used differs between running and stagnant water based on the shape of the water. Fishery resources in Indonesia, especially inland fisheries, still cannot be managed and utilized optimally and sustainably. The method used in estimating fishery stocks in the watershed is the Leger-Huet method. Research to estimate fish production potential using the benthic biomass approach using the Leger-Huet method was carried out in February, June, and October 2019 in the Sumani River and Ombilin River, Singkarak Lake. The research objective was to determine the estimated value of fish production potential through the benthic biomass approach in the Sumani River (Inlet) and Ombilin River (Outlet), Singkarak Lake. The calculation of benthic biomass and fish production potential was carried out at the Testing Laboratory of the Research Institute for Inland Fisheries and Extension in Palembang. This system is expected to be able to provide alternative solutions for decision-making and agencies to determine the potential for fish production in an area. The determination of the potential for fish production using the benthic biomass approach is highly dependent on the width of the river. The results showed that the types of benthos in the Sumani and Ombilin rivers were 5 classes and 17 families. The benthos found by the Ombilin River are more varied than those in the Sumani River, and the estimated fish production potential of the Ombilin River is greater than that of the Sumani River. The highest yield of benthic biomass was found in the Ombilin River (159.06 gr/m2) compared to the Sumani River (76.06 gr/m2). Meanwhile, the average potential fish production in the Batang Sumani River (573.8 (kg/ha) is higher than in the Ombilin River (244.74 kg/ha).