Jurnal Ilmu Perikanan Tropis Nusantara (Nusantara Tropical Fisheries Science Journal)
Nusantara Tropical Fisheries Science adopts a broad, interdisciplinary approach to the subject of fish biology and fisheries. It draws contributions in the form of major synoptic papers and syntheses or meta-analyses that lay out new approaches, re-examine existing findings, methods or theory, and discuss papers and commentaries from diverse areas. Nusantara Tropical Fisheries Science is published biannually in February and August
Faculty of Fisheries and Marine Science, Mulawarman University
The Relationship between Rainfall and Total Suspended Solids (TSS) in Stormwater Runoff within a Coal Mining Stockpile Area
This study aimed to analyze the relationship between rainfall characteristics and Total Suspended Solids (TSS) concentrations in stormwater runoff within a coal mining stockpile area. The study is considered important because it provides a scientific basis for understanding the influence of rainfall on TSS concentrations, while also supporting the evaluation of sediment control measures, operational improvements, and the development of sustainable environmental management policies. The data used in this study consisted of inlet TSS concentrations and daily rainfall records, which were categorized into rainfall measurements on the same day as TSS sampling (H0), rainfall measurements one day prior to TSS sampling (H1), rainfall measurements two days prior to TSS sampling (H2), and the cumulative rainfall from these three rainfall measurement variations. Observations were conducted at a monitoring point located in Loa Kulu Kota Village, Loa Kulu District, during the 2019–2025 period. The analysis was performed using polynomial regression statistics and correlation tests. The results showed that the average TSS concentration was relatively low (<100 mg/L), although several extreme spikes reaching up to 750 mg/L were recorded. In contrast, rainfall exhibited a more stable pattern (<150 mm). Polynomial regression analysis produced low coefficients of determination (R²), with the highest value observed under the H0 condition (R² = 0.1476), while H1 and H2 yielded only 0.0242 and 0.0088, respectively. Correlation tests further indicated that there was no statistically significant relationship between rainfall and TSS concentrations (p > 0.05). These findings suggest that increases in TSS concentrations are more strongly influenced by non-hydrological factors, such as mining operational activities, land cover conditions, and the effectiveness of sediment control infrastructure.
Copyright (c) 2026 Jurnal Ilmu Perikanan Tropis Nusantara (Nusantara Tropical Fisheries Science Journal) https://creativecommons.org/licenses/by-nc-sa/4.0
Types of mesoplastic waste in the Manggar Beach tourism area, Balikpapan City, East Kalimantan
Plastic waste poses a significant threat to the global environment, particularly in coastal and marine ecosystems. Among its various forms, mesoplastics, measuring between 5 and 25 mm have attracted considerable attention. This study aims to identify and analyze the types, weights, quantities, compositions, and densities of mesoplastics found along Manggar Beach, a tourist destination in Balikpapan City, East Kalimantan. Sampling was conducted in two periods: April (Period I) and August (Period II) of 2022. A purposive sampling method was applied using a 100-meter transect line divided into 5x5 meter lanes, followed by the placement of 1x1 meter quadrats. In Period I, four types of mesoplastics were identified as film, fiber, fragments, and styrofoam, while only film was detected in Period II. A total of 43 mesoplastic particles (weighing 9.45 grams) were recorded in Period I, compared to just 5 particles (0.15 grams) in Period II. By weight, styrofoam made up the largest proportion (49%) in Period I, whereas film accounted for 100% in Period II. The average mesoplastic density observed in this study was 0.38 particles per square meter.
Copyright (c) 2025 Jurnal Ilmu Perikanan Tropis Nusantara (Nusantara Tropical Fisheries Science Journal) https://creativecommons.org/licenses/by-nc-sa/4.0
Leadership analysis of the Bengkuring Karya Fish Farming Group in East Sempaja Subdistrict, Samarinda City
Leadership is a fundamental element that significantly determines the operational success and achievement of a group’s vision. The success of an organization or business group, including fish farming groups, largely depends on the effectiveness of its leader in managing available human resources. This effectiveness is also influenced by the socio-economic characteristics of group members, which may affect the dynamics of cooperation and communication within the group. This study aims to examine the socio-economic characteristics of members and to analyze the leadership style implemented in the Bengkuring Karya Fish Farmers Group (Kelompok Pembudidaya Ikan, Pokdakan), located in East Sempaja Subdistrict, Samarinda City. The study employed a descriptive quantitative approach with a total sampling technique involving the entire population of 12 respondents, consisting of group administrators and active members. Data analysis was conducted using descriptive analysis to interpret respondents’ responses, as well as DeVito’s leadership theory to identify the leadership style applied. The results show that the majority of group members are aged between 36–45 years, have completed senior high school/vocational education, have low participation in non-formal education, possess low to moderate income levels, have been members of the group for approximately four years, and most are married. Based on the analysis, the dominant leadership style is democratic leadership, characterized by member participation in decision-making processes as well as open and collaborative communication between the group leader and members.
Analysis of the Seawater Quality Index in the Marine Waters of Bontang City, East Kalimantan
Seawater quality is a key factor in determining the health of coastal ecosystems and the sustainability of marine resources. Anthropogenic activities such as the discharge of industrial and domestic waste, marine transportation, and intensive fishing practices can influence the physical, chemical, and biological parameters of seawater. Research on seawater quality in the marine waters of Bontang City has been conducted, but remains very limited in number. This study aims to analyze the Seawater Quality Index (IKAL) in the marine waters of Bontang City. The analytical method employed refers to the Regulation of the Minister of Environment and Forestry of the Republic of Indonesia No. 27 of 2021. The results indicate that the average Seawater Quality Index (IKAL) in Bontang City during the second semester of 2023 was 72.69, which is categorized as good condition.
The concentration of Mn and Fe metals in water and sediment of the Sanga-Sanga River, East Kalimantan Province
This study aimed to analyze the concentrations of manganese (Mn) and iron (Fe) in both water and sediment samples from the Sanga-Sanga River, Kutai Kartanegara Regency, East Kalimantan Province. The research was conducted from October to December 2024 at three stations representing the upstream, midstream, and downstream sections of the river. Sampling was performed using a purposive method based on site characteristics, and analyses were carried out both in situ and at the Water Quality Laboratory, Faculty of Fisheries and Marine Science, Mulawarman University. The concentrations of Mn and Fe were compared with the Indonesian river water quality standard (Government Regulation No. 22 of 2021) and sediment quality guidelines established by the Australian and New Zealand Environment and Conservation Council (ANZECC, 2000). The results showed that Mn concentrations in river water ranged from 0.325 to 1.181 mg/L, exceeding the permissible limit of 0.1 mg/L, while Fe concentrations ranged from 0.3475 to 0.468 mg/L, surpassing the standard of 0.3 mg/L. In sediments, Mn concentrations ranged from 42.38 to 964.47 mg/kg and Fe concentrations from 11,341.23 to 50,344.72 mg/kg, with several stations exceeding the ANZECC guideline limits. Higher concentrations were generally found at midstream and downstream stations, particularly in areas influenced by coal mining, barge transport, and ship repair activities. These findings indicate that the Sanga-Sanga River has experienced notable contamination by Mn and Fe, primarily due to anthropogenic activities related to coal industry operations. Continuous monitoring, stricter waste management, and the implementation of pollution control measures are recommended to prevent further environmental degradation and protect aquatic ecosystems.
Characteristics of microplastics in the digestive system of spotted scat (Scatophagus argus) from Pangempang, Muara Badak, Kutai Kartanegara, East Kalimantan
Indonesia produces approximately 5.4 million tons of marine debris, making it the second-largest contributor of ocean waste in the world. This fact illustrates that all plastic waste discarded on land eventually ends up in the ocean. This study aims to understand the characteristics of microplastics in spotted scat (Scatophagus argus) and to determine whether there is a relationship between the length of the fish and the abundance of microplastics. The procedure involved several stages, including literature review, field surveys, sample collection, dissection of the fish’s digestive tract, and identification of microplastics using a Relife RL-M3T microscope at 10–20X magnification. Microplastic particles were separated using 22% KOH and 20% H₂O₂ solutions. The results showed that, from 10 fish samples analyzed, a total of 182 microplastic particles were found. The most dominant type was fiber, followed by film and fragment, with an average abundance of 18.2 particles per individual. This research is expected to serve as a reference for the sustainable management of aquatic environments and to provide essential information for plastic waste control policies.
Feasibility Analysis of Mangrove Syrup Enterprises and Institutional Patterns of the Daun Harum and Talitah Groups in Tanjung Laut Indah, Bontang City, Indonesia
Bontang City, located in East Kalimantan Province, has an extensive coastal area with well-preserved mangrove ecosystems. These mangrove resources have not yet been fully optimized to enhance the economic well-being of local communities. One of the utilization efforts currently undertaken is the processing of Sonneratia ovata mangrove fruit into high-value mangrove syrup. The Daun Harum Group, based in Tanjung Laut Indah Sub-district, has developed a mangrove syrup production enterprise as a flagship local product, in collaboration with the Talitah Group, which acts as the supplier of raw materials. This study aims to analyze the financial feasibility of the mangrove syrup business and to describe the institutional partnership established between the two groups. The research was conducted over nine months, from August 2024 to May 2025. Both primary and secondary data were utilized. Primary data were collected through direct observation and interviews with respondents, while secondary data were obtained through literature review. Respondents in this study consisted of the management and members of both Daun Harum and Talitah Groups. Respondents were selected using purposive sampling, with the following criteria: (1) actively involved in managing the group, (2) knowledgeable about the group’s organizational management, and (3) willing to collaborate with the researcher in providing the required data and information. Based on these criteria, the total number of respondents was eight (8) individuals (2 administrators and 2 members from each group). Data were analyzed using business feasibility analysis and institutional descriptive analysis. The results of the study indicate that the mangrove syrup business is financially viable, with a Net Profit IDR 14,433,358 a Revenue Cost Ratio (RCR) of 1.41, a Payback Period (PP) of 0.06 years, and a Return on Investment (ROI) of 128.5%. The institutional structure that emerged represents a marketing and credit-based institution, which functions effectively in terms of jurisdictional boundaries, ownership rights, and rules of representation. This study demonstrates that the collaboration between two local institutions focused on mangrove resource management can serve as a strategic approach to sustainable economic empowerment for coastal communities
Abundance and Morphometric Characteristics of the Sea Urchin Diadema setosum in Seagrass Beds of Malahing Village Waters, Bontang City, East Kalimantan, Indonesia
Seagrass meadows are vital coastal ecosystems that support biodiversity and ecological balance, particularly in Bontang City, East Kalimantan. This study investigated the ecological relationship between seagrass meadows and the sea urchin Diadema setosum through field sampling conducted from October 2024 to February 2025 in Malahing Village. Data collection included seagrass density, physicochemical water parameters, sediment composition, and sea urchin abundance and morphometrics. Results showed that substrates were dominated by sandy textures (average 89.2%), suitable for sea urchin habitats. Seagrass density varied among species, with Enhalus acoroides dominating northern stations and Thalassia hemprichii thriving in eastern and southern stations. The total abundance of D. setosum reached 480 ind/m², with the highest density at the eastern station. Morphometric analysis revealed negatively allometric growth, where test diameter increased faster than body weight. Correlation analysis indicated a strong positive relationship between D. setosum abundance and T. hemprichii density (r = +0.896), but a weak negative correlation with E. acoroides (r = −0.712). These findings highlight the species-specific interactions between sea urchins and seagrass, emphasizing the role of T. hemprichii in supporting sea urchin populations and the importance of mixed seagrass beds in maintaining coastal ecosystem health.
Characteristics of the Distribution Pattern and Density of Enhalus acoroides in the Waters of Malahing Village, Bontang City, East Kalimantan, Indonesia
Enhalus acoroides is one of the most widely distributed seagrass species in the coastal waters of Bontang, East Kalimantan, Indonesia. This study aimed to determine the distribution pattern characteristics and density of Enhalus acoroides in the waters of Malahing Village, Bontang City, East Kalimantan. The research was conducted from October 2024 to February 2025. Seagrass vegetation data were analyzed using species density, relative density, species frequency, relative frequency, species coverage, relative coverage, and the Important Value Index (IVI). The distribution pattern of seagrass was assessed using the Morisita Dispersion Index (MDI), while environmental factors influencing the distribution pattern were described and presented in observational tables. Sampling was carried out using 50 × 50 cm quadrats along transects at each station with three replications. The results revealed the presence of two seagrass species in the waters of Malahing Village, namely Enhalus acoroides and Thalassia hemprichii, with E. acoroides being the dominant species. Seagrass density across the four sampling stations ranged from 92 to 216 shoots m⁻². The Morisita Dispersion Index (MDI) analysis indicated that Enhalus acoroides exhibited a uniform distribution pattern, as evidenced by an index value of Id < 1.
Production Analysis of Nile Tilapia (Oreochromis niloticus) Cultivation in Floating Net Cages in Loa Kulu District: A Case Study
This study aimed to analyze the financial feasibility of Nile tilapia Oreochromis niloticus aquaculture conducted using floating net cages in Loa Kulu District. The research employed a case study approach, with data collected through direct observation, interviews, and participation in ongoing aquaculture activities at the study site. The collected data included information related to production aspects and the financial conditions of Nile tilapia farming operations in the field. The financial analysis of the “Sumber Rezeki” Nile tilapia (Oreochromis niloticus) farming enterprise in Sepakat Village demonstrated profitability and feasibility. The business generated an annual net profit of IDR 13.48 million, with positive investment indicators: NPV = IDR 73.99 million, IRR = 89%, Net B/C = 3.55, and a Payback Period of 1.41 years. Both production and sales exceeded break-even points, confirming the enterprise’s viability and sustainable operation.
Perceptions of fishers in the Mutiara Indah Teritip Joint Business Group (KUB) on the Role of the Food, Agriculture, and Fisheries Agency (DP3) in East Balikpapan District, Balikpapan City
Although fisheries institutions have developed, most remain small-scale operations managed traditionally, with weak management practices and limited access to information and technology. Understanding community perceptions is therefore essential. This study aims to examine fishers’ perceptions, both cumulatively and partially, within the Joint Business Group (Kelompok Usaha Bersama/KUB) Mutiara Indah Teritip regarding the role of the Food, Agriculture, and Fisheries Agency (Dinas Pangan, Pertanian dan Perikanan/DP3) in East Balikpapan District, as well as to identify the challenges faced by DP3 in this area. The research was conducted from September 2024 to May 2025 in East Balikpapan District, Balikpapan City. A total of 17 respondents were selected using purposive sampling. The results showed that the cumulative perception score of fishers in KUB Mutiara Indah Teritip regarding the role of DP3 reached 40.18, which falls within the range of 35.02–45.00 and is categorized as high. Similarly, the partial perception scores were also categorized as high, with indicator values as follows: program development for fishing activities (8.29), policy formulation for fisheries (8.35), supervision of fishing permits (8.41), guidance and training for fishers (7.88), and the application of fishing technology (7.24).
Visitor Perceptions of the Educational Fish Pond Tourism Site in Sumber Rejeki Hamlet, Loh Sumber Village, Loa Kulu, East Kalimantan
The Educational Tourism Fish Pond of Sumber Rejeki Hamlet, Loh Sumber Village, serves as a potential medium for introducing fisheries-related activities, including aquaculture, aquatic resource management, and the sustainable application of fisheries technology to the community. The objective of this study was to examine visitors’ perceptions of the educational tourism fish pond in Sumber Rejeki Hamlet, Loh Sumber Village, Loa Kulu Subdistrict. The research was conducted from November to December 2024 using the accidental sampling method. The respondents consisted of 45 visitors to the tourism site. Data were analyzed using descriptive analysis with a Likert scale measurement. The results indicate that visitors’ perceptions of the educational tourism fish pond fall into the “very good” category (87.05), within the score range of 87–103. This evaluation was based on the following indicators: tourism object (13.38, very good), accessibility (7.87, good), facilities (39.64, very good), information and promotion (17.29, very good), and management services (8.87, good).
Profit and loss analysis of Fish Hatchery Operations at the Brackish and Marine Water Hatchery Center, Sebulu Ulu Village, Kutai Kartanegara Regency
This study aims to analyze the profit and loss of fish hatchery operations at the Regional Technical Implementation Unit (UPTD) for Brackish and Marine Water Hatchery, located in Sebulu Ulu Village, Sebulu Subdistrict, Kutai Kartanegara Regency, as well as to identify the driving and inhibiting factors of the business. The research was conducted from November 2023 to December 2024 at the UPTD Brackish and Marine Water Hatchery Center in Sebulu Ulu Village. The study utilized both primary and secondary data, with sampling carried out using a census method involving 6 respondents. The results showed that the hatchery operations, which focus on four fish commodities—Nile tilapia (Oreochromis niloticus), catfish (Pangasius sp.), African catfish (Clarias sp.), and climbing perch (Anabas testudineus)—incurred a Total Cost (TC) of IDR 309,644,087 per year, while generating a Total Revenue (TR) of IDR 253,156,140 per year. Consequently, the business experienced a loss of IDR 56,487,947 per year. The identified driving factors include a strategic location, adequate water resources, availability of electricity, high market demand for fish seed, and government support. In contrast, the inhibiting factors are limited labor availability, inadequate facilities, climatic factors, and the quality of broodstock.
Ecological Parameters and Tourism Suitability of Mangrove Ecosystems in Bontang Mangrove Park Saleba, East Kalimantan
This study evaluates the suitability of mangrove ecotourism in Bontang Mangrove Park (BMP) Saleba, East Kalimantan, by integrating ecological parameters with social insights. Key indicators such as mangrove thickness, density, species diversity, and biota associations were analyzed alongside tidal dynamics and community perceptions. Using the Importance Value Index (IVI) and Tourism Suitability Index (IKW), results show that BMP Saleba’s mangrove ecosystem is classified as “very suitable” for ecotourism, with Rhizophora mucronata dominating across growth stages and supporting high biodiversity. Dense vegetation, stable tidal conditions, and favorable substrate characteristics further reinforce ecological resilience. Combined with community recognition of mangroves as ecological and cultural assets, these findings highlight BMP Saleba’s readiness for sustainable ecotourism development, contributing to conservation strategies and local economic opportunities.
Study on the dynamics of Fish Farmer Group (Pokdakan) in Bukit Pinang Village, Samarinda Ulu District, Samarinda City
The aim of the research, is to determine the profile of the Rejang Raya Lake fish cultivator group (Pokdakan), and to find out the level of dynamism of the Rejang Raya Lake fish cultivator group (Pokdakan). The sampling method used was the census method with the number of respondents taken as many as 10 respondents. The analytical method used is a Likert scale to determine the level of dynamics of the Rejang Raya Lake fish cultivator group for each indicator: group goals, group structure, group tension, group effectiveness, hidden intentions are in the high category. The level of dynamics of the Rejang Raya Lake Fish Cultivator Group (Pokdakan) cumulatively obtained a score of 79.90, which is at a high level in the range of 63-81 and can be interpreted that the level of dynamics of the group is at high criteria (already dynamic) or the management and members it's been going well.
Analysis of heavy metal content (Pb, Cu, Cd, and Fe) in the seagrass Thalassia hemprichii as a bioindicator of marine pollution in Tihi-Tihi Village, Bontang City, East Kalimantan
The waters of Bontang City have relatively productive anthropogenic activities that trigger changes in the quality of surrounding waters that have the potential for pollution in the waters of the Bontang City area and there is a seagrass ecosystem that can be used as a natural indicator because it is sensitive to the presence of pollutants. To answer the problems found, this final project aims to determine the concentration levels of heavy metals (Pb, Cu, Cd, and Fe) contained in seagrass Thalassia hemprichii species in the waters of Tihi-Tihi Village. This study uses descriptive methods and location determination using the purposive sampling method and heavy metal analysis in water samples, sediments, and seagrass T. hemprichii analyzed using the AAS (Atomic Absorption Spectrophotometry) tool. The results showed that the waters of Tihi-Tihi Village had been contaminated with the heavy metal content of Pb, Cu, Cd, and Fe with different concentration levels, the metal content in water ranged from <0.001-0.098 mg/L, in sediment ranged from 2.64-1063.53 mg/kg and in seagrass ranged from 0.02-3468.08 mg/kg.
Identifying the characteristics of visible (macro) litter in the Mangrove Park Berbas Pantai Area, Bontang City, East Kalimantan Province
Ecotourism areas are locations where human activities are prevalent in the surrounding environment, including settlements, trade, and other activities that contribute to the community’s economic, social, and cultural development. However, these activities can also pose a potential threat to environmental quality if not properly managed. A study conducted at the Mangrove Berbas Pantai area, Bontang City, aimed to identify the types, quantity, and abundance of visible (macro) waste. Sampling was carried out using purposive sampling methods. A 100 m x 20 m transect line was placed parallel to the mangrove ecotourism trail, considering areas that visually contained significant amounts of waste. This transect was divided into five lanes, each containing sub-transects measuring 5 m x 5 m as the sampling areas. Visible (macro) waste identified at the research location includes plastic, rubber, metal, glass, and wood. The composition of waste by weight shows that glass waste has the highest percentage by weight (59.2%), even though it is not the most abundant in number. Polynomial analysis indicates a low influence (21%) between waste type composition and waste weight, while the correlation is 46%.
Analysis of the impact of Tilapia Aquaculture Village Development (Oreochromis niloticus) on the welfare of fish farmers in Ponoragan Village, Loa Kulu District, Kutai Kartanegara Regency
This study aims to analyze the impact before and after the implementation of Ministerial Regulation of Marine Affairs and Fisheries (Permen-KP) No. 16 of 2022 on the Tilapia Aquaculture Village in Ponoragan Village on household income, employment absorption, and to identify the main challenges faced by fish farmers. The sampling method used was purposive sampling, with a total of 30 tilapia farmers as respondents and two key informants. The data were analyzed using income analysis, average income difference analysis with a T-test, and labor absorption analysis. The study results show that the average income of tilapia farmers before the implementation of the aquaculture village policy was IDR 120,569,272 per month, increasing to IDR 606,954,928 per month after implementation. This indicates a rise in the average income of fish farmers by IDR 486,385,656 following the policy's implementation. The implementation of the aquaculture village policy also had an impact on labor absorption, both from within and outside the family. Before the policy was implemented, the percentage of labor from within the family was 0.01228 percent, increasing to 0.01283 percent after implementation. Meanwhile, the percentage of labor absorption from outside the family increased from 0.01283 percent to 0.01897 percent. This increase reflects the additional workforce employed, both from within and outside the family, in response to increased production, income, and the farmers' commitment to involving the surrounding community. The main challenges faced by tilapia farmers include extreme weather conditions that often cause harvest failures, river water intrusion into ponds, which increases water volume and leads to fish escaping, and the use of pesticides by farmers to control fish pests and predators. These findings illustrate that the aquaculture village policy has great potential to improve farmers' welfare, but it must be accompanied by mitigation efforts to address existing challenges.
Water quality assessment using the STORET method and formulation of pollution control strategies in the Sangatta River, East Kutai Regency, Indonesia
The Sangatta River, located in East Kutai Regency, East Kalimantan, is a vital water resource that plays a significant role in supporting both local communities and ecosystems. However, the increasing pressure on this river necessitates regular monitoring to assess its water quality status. This study aims to assess and analyze the water quality of the Sangatta River, determine its water quality status, and identify potential measures for controlling water pollution in the river. The research employed the STORET method. Based on this method, the results were as follows: -22 (upstream 1), -34 (upstream 2), -50 (downstream 1), -54 (downstream 2), and -40 (downstream 3). These findings indicate that the Sangatta River is classified as heavily polluted, with an overall score of -40 according to the STORET method. Efforts to control river water pollution should focus on social and institutional aspects, particularly by enhancing community participation in pollution control efforts for the Sangatta River.
The relationship between salinity and pond area in the Mahakam Delta, East Kalimantan
This study aims to analyze the relationship between salinity and the extent and type of mangrove vegetation in ponds within the Mahakam Delta, East Kalimantan. Sampling was conducted in ponds with different salinity levels: 0–10 ppt, 11–20 ppt, and 21–30 ppt, with each salinity category represented by 10 pond plots. Data analysis was performed using linear regression. The results showed a strong relationship between salinity variation and pond area, with an r-value of 0.630. The extent of pond expansion is related to the original mangrove type present in the pond area. This information can be used as a basis for determining suitable aquatic species for cultivation based on salinity levels. In other words, the selection of aquatic species for cultivation can be adjusted according to the appropriate pond area. Further research is needed to determine whether other factors influence the relationship between salinity levels and pond area in the Mahakam Delta region.
Analysis of water fertility status based on the Trophic State Index (TSI) in the Air Hitam Urban Polder, Samarinda Ulu District, East Kalimantan
Waters near urban centers are highly vulnerable to pollution, a condition likely occurring in the Air Hitam Polder in Samarinda, which receives inflow from urban drainage and is surrounded by intense human activity. This study aimed to determine the Polder’s trophic status using the Carlson Trophic State Index (TSI) based on water transparency, total phosphate, and chlorophyll-a, analyzed spatially and temporally. It also assessed general water quality and examined the relationship between nutrients (phosphate, nitrate, ammonia) and chlorophyll-a. Measurements at five stations included transparency, chlorophyll-a, DO, EC, TDS, temperature, pH, and turbidity, with laboratory analyses for phosphate, nitrate, and ammonia. Sampling was conducted six times. Results show Station 3 had the highest TSI (75.25), likely due to its location near the main inlet carrying organic and inorganic materials. Temporally, the Polder was classified as hypereutrophic, with TSI values >60 at all stations. Phosphate had the strongest relationship with chlorophyll-a. Several parameters (DO, EC, TDS) met water quality standards, while others (phosphate, nitrate, ammonia, temperature, pH, transparency, turbidity) exceeded limits. Overall, current conditions are unsuitable for aquatic life, indicating the need for improved management to restore the ecological function of the Air Hitam Polder.
Habitat Characteristics and Morphometrics of Starfish (Archaster typicus) in the Seagrass Ecosystem of the Waters of Malahing Hamlet, Bontang City
The purpose of this study was to determine the habitat and morphometric characteristics of Archaster typicus in seagrass beds and to determine the density and composition of seagrass in the Malahing Hamlet Waters, Bontang City. The study was conducted from June - September 2024. The research locations were grouped into 3 research stations (North, East, South) with quadrant transects. Starfish identification data were analyzed using seagrass density and Regression correlation. Archaster typicus is relatively common in shallow waters, and the habitat found is on sand flats. The highest and lowest average morphometric character results in arm length were at the eastern station 4.5 ± 0.7 cm and the lowest at the southern station 4.2 ± 0.6 cm, the highest body height at the eastern station 0.7 ± 0.2 mm and the lowest at the southern station 0.4 ± 0.2 mm, the highest arm base width at the eastern station 1 ± 0.1 mm and the lowest at the northern station 0.9 ± 0.1 mm, the highest overall diameter at the southern station 8.2 ± 1.5 cm and the lowest at the northern station 8.4 ± 0.7 cm, the highest bodyweight at the eastern station 7.6 ± 2.4 grams and the lowest at the northern station 7.3 ± 1.4 grams, the highest distance between arms at the southern station 5.6 ± 1.1 cm and the lowest at the northern station 5.1 ± 0.6 cm.
Water quality characteristics in the waters of Pangempang, Muara Badak, East Kalimantan
The Pangempang waters, located within the estuarine area of Muara Badak, have experienced continuous coastline changes due to annual erosion. Monitoring water conditions in this region is essential to evaluate environmental suitability and detect potential threats. This study examined the physical and chemical properties of the water, following the guidelines of Government Regulation No. 22 of 2021. Observations were conducted at five selected sites: a shrimp pond, a river area adjacent to the pond, the river mouth near mining activities, a tourist area on Pangempang Island, and the outer section of the island near the dock, representing the Pangempang waters. Overall, the results indicate that water quality remains within acceptable limits for marine biota. However, certain parameters, such as temperature, salinity, and nitrate levels, deviated from the established standards. These variations are influenced by weather conditions, location, and potential organic waste input from activities along the study area.
Study of shoreline changes using Landsat Satellite Imagery in Tanjung Tengah and Saloloang Villages, Penajam District
The coastal areas of Tanjung Tengah and Saloloang sub-districts that used as ecotourism, this research needed to determine changes in the coastline at these locations. The study aims to determine the shift of the coastline along with the extent of abrasion and accretion for 15 years on the coast in Tanjung Tengah and Saloloang Villages, Penajam District, Penajam Paser Utara Regency. The study was conducted from October 2023 to November 2023. The method used is the Digital Shoreline Analysis System (DSAS) analysis using Landsat 7 ETM and Landsat 8 OLI satellite imagery obtained from the USGS site. The results of the study showed that during the period 2009 - 2023 along the coastal areas of Tanjung Tengah and Saloloang Villages, was greater accretion than abrasion, period 2009-2015 the coast experienced a shift towards the sea (Accretion) reaching 311.95 meters. Then experienced a retreat towards the land reaching 267.11 meters from the period 2015-2023. The total area of ​​the area experiencing accretion and abrasion respectively is 81.42 ha and 41.68 ha.
Macrozoobenthos diversity at Istana Amal Beach, Penajam Paser Utara Regency, East Kalimantan
Istana Amal Beach, located in Penajam Paser Utara, East Kalimantan, is one of the region's ecotourism destinations. One of the key indicators of environmental quality in this area is the presence of macrozoobenthos. This study, conducted in December 2023, aimed to identify the types of macrozoobenthos present, calculate the diversity, evenness, and dominance indices, and assess the physical and chemical parameters of the water at Istana Amal Beach. A purposive sampling method was applied at two stations, selected based on different activity types in the area. The results revealed the presence of macrozoobenthos from two classes: Gastropoda and Bivalvia, comprising a total of 16 species. The ecological index values indicated a moderate diversity (H' = 2.2), high evenness (E = 0.8), and low dominance (D = 0.1), suggesting a relatively balanced ecosystem. Water quality measurements at both sampling points showed a salinity of 30 ppt, pH averaging 7.65, temperature of 30°C, and dissolved oxygen levels averaging 5.2 mg/L. The substrate at the site was identified as having a sandy texture.
Identification of types and abundance of microplastics in coastal sediments of Tanjung Jumlai Beach, North Penajam Paser Regency, East Kalimantan
The existence of microplastics is affected by the many activities in the community related to the use of plastic, as well as uncontrolled disposal of plastic waste so that plastic waste enters the waters through water flows and will degrade into smaller sizes. This research aims to identify the type, abundance, and composition, as well as determine differences in abundance between types of microplastics in Tanjung Jumlai Beach sediments. Sampling was conducted by drawing a transect line 100 meters long, then dividing it into 5 lanes each measuring 20 meters. Each lane was subdivided into sub-transect boxes measuring 5×5 meters. Then, within each 5×5 meter sub-transect, 1×1 meter sub-transect boxes were created, making 25 sub-transect boxes of 1×1 meter in each 20-meter lane. From these, 5 boxes were selected using randomizer application. Sediment samples that have been processed were then identified using a microscope. There were three types of microplastics found in Tanjung Jumlai beach, namely 65% fragments with an abundance of 10.340 particles/kg/m2, 19% fiber with an abundance of 2.960 particles/kg/m2, and 16% film with an abundance of 2.580 particles/kg/m2. There is a significant difference in abundance between fragment microplastics and film and fiber microplastics. There is no significant difference in abundance between film microplastics and fiber microplastics found on the coast of Tanjung Jumlai, Penajam Paser Utara Regency, East Kalimantan.
Analysis of microplastic content in sediments of two garden ponds located in the Mulawarman University Campus
Plastic waste is the type of waste that is most commonly found in our environment. Plastic waste that decomposes and degrades into smaller particles is called microplastic. Small-sized microplastics (<5 mm) can accumulate in water sediments and are difficult to decompose, making this material remain in the environment for a long time. This research aims to determine the microplastic content in the sediment of the main gate garden pond and FEB garden pond at Mulawarman University. This research was carried out for 3 months starting from determining the research location until microplastic analysis. The research location was determined by purposive sampling in 2 garden ponds with 5 stations in each pond. Analysis of microplastic content in sediment was carried out using a separation method based on specific gravity using NaCl solution. Microplastic identification was carried out using a stereo microscope (8-16x magnification). The results of this research show that the types of microplastics found were fiber, fragments and films with the dominant type of microplastic being fiber. The highest abundance of microplastics was found in the FEB garden pond at 4,350 particles/kg, while in the main gate garden pond, it was 3,800 particles/kg.
Microplastic abundance in sediments of the artificial ponds at Mulawarman University, Samarinda, East Kalimantan
Microplastics present in the environment, particularly in sediments, pose potential threats to aquatic organisms, as they can impair organ function when ingested. This study aims to assess the abundance, types, and colors of microplastics in the sediments of the artificial pond at Mulawarman University, Samarinda. The research employed a purposive sampling method. The Faculty of Agriculture pond had a higher microplastic abundance compared to the UNMUL HUB pond. Nonetheless, statistical analysis using a t-test showed no significant difference in microplastic levels between the two sites at Mulawarman University, Samarinda (p-value > 0.05). Overall, the artificial ponds at Mulawarman University, East Kalimantan, contained an average of 275 particles of microplastic per kilogram of dry sediment. Specifically, the Faculty of Agriculture pond had 161.25 particles/kg, while the UNMUL HUB pond had 113.75 particles/kg. The microplastics found consisted of fibers, fragments, films, and pellets, with colors including black, blue, red, brown, yellow, and white.
Water quality monitoring of Polder Air Hitam Lake in Samarinda
This study aimed to evaluate the water quality status of Polder Air Hitam Lake, Samarinda, through monitoring several key water quality parameters and comparing the results with the Indonesian water quality standard (PP RI No. 22 Tahun 2021, Class II). Sampling was conducted from September to November 2023 at five monitoring stations. The measured parameters included chlorophyll-a, Dissolved Oxygen (DO), pH, temperature, Total Dissolved Solids (TDS), turbidity, salinity, and electrical conductivity. The results showed that chlorophyll-a concentrations ranged from 20.67–148.00 µg/L, indicating relatively high phytoplankton productivity, with several observations exceeding the quality standard threshold. DO concentrations ranged from 3.36–10.45 mg/L, while pH values ranged from 7.49–9.61, indicating slightly alkaline conditions. Temperature (27.2–31.27°C), TDS (172–215 ppm), and salinity (0.01–0.02‰) generally remained within acceptable ranges for freshwater ecosystems. Turbidity values (40–121 NTU) indicated considerable suspended materials that may reduce light penetration and affect aquatic productivity. Overall, the water quality of Polder Air Hitam Lake was generally within acceptable standards for several parameters; however, elevated chlorophyll-a, pH, and turbidity values suggest potential anthropogenic influences and indicate the need for continued monitoring and management efforts.
Survival strategies of gill net fishermen households in North Bontang District, Bontang City, East Kalimantan
This study aims to determine the socio-economic conditions and survival strategies of gillnet fishermen households in maintaining their lives. The research was conducted for 11 months from July to May 2024 in Bontang Kuala Village, North Bontang District, Bontang City. The method used in sampling fishermen is simple random sampling with a total of 34 respondents. The analysis method uses qualitative descriptive analysis. The results showed that the socio-economic conditions of the majority of gill net fishermen were productive age 53-59 years, the average education level was elementary school 26 people, fishermen's income ranged from IDR 420,000 - IDR 3,000,000 per month with an average per fisherman IDR 2,031,470. Their status is owner fishermen with fishing fleets in the form of boats with no engine, boats with ketinting engines and boats or boats with dompeng engines. Fishermen's residences are generally semi-permanent houses with good physical conditions and the land ownership status of the house building is Hak Guna Bagunan (HGB). Fishermen's survival strategies are carried out in three ways, namely, active strategies by doing side jobs, optimising the role of family members (wife and children) and increasing working hours at sea. Passive strategies, reducing the cost of food, clothing, education and setting aside money or saving money from fish sales. Network strategies, making loans through horizontal social networks (family) and vertical social networks (collectors), as well as economic or financial institutions, such as cooperatives, banks, People's Business Credit (PBC) through fisheries organisations and utilising poverty programs.