Jurnal Kelautan Tropis is a journal published by the Department of Marine Science Faculty of Fisheries and Marine Sciences, Diponegoro University and Indonesian Environmental Examiner Association (INKALINDO). Jurnal Kelautan Tropis receives manuscript research and review on marine biology, marine ecology, geology and marine geodesy, marine fisheries (processing, species of diversity, fishing gear), oceanography, marine pollution, remote sea sensing, marine microbiology and coastal management. Jurnal Kelautan Tropis published three time a year, in March, June and November. The first published in 1998 is still in printed. Jurnal Kelautan Tropis is already available online version at 2015 (Vol 18 no 1) and all processes have been by online. This journal is Nationally Accredited by Directorate General of Higher Education decree No.: 105/E/KPT/2022 at 7 April 2022 by Ministry of Education, Culture, Research, and Technology Indonesian. Accredited issue are Volume 24 No 1 (2021) until Volume 28 No 2 (2025) P-ISSN : 1410-8852 E-ISSN : 2528-3111
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Profil Populasi Tuna Madidihang (Thunnus albacares Bonnaerre, 1880) yang Tertangkap pada Perikanan Handline di Perairan Nusa Tenggara Timur dan sekitarnya
Yellowfin tuna (Thunnus albacares) is the main target of capture fisheries in various tropical waters, including Indonesia, owing to its high economic value. Global market demand increases the rate of exploitation; therefore, the size of the catch is not considered. The increasing number of fishing units led to declines in tuna stocks, catches exceeding the limit, and a dominance of catch sizes smaller than the mature gonad size (Lc < Lm), resulting in a decrease in the biomass of spawning stocks. This study aimed to examine the profile of the yellowfin tuna population in the waters of East Nusa Tenggara (NTT) by analyzing its size structure, size-at-first-catch (Lc), mortality, recruitment patterns, production trends, and Catch Per Unit Effort (CPUE). Length and weight data were obtained from I-Fish (Indonesian Fisheries Information System) initiated by YMDPI. The analysis showed that the yellowfin tuna caught ranged in size from 78 to 173 cm and were dominated by the 94-125 cm size group (82.86%). The catch consisted of 99.99% adult fish and 0.01% juveniles. The Lc value ranged from 103.34–106.55 cm, fishing mortality (F=1.44) was higher than natural mortality (M = 0.71) and the exploitation rate (E) was 0.67, indicating overfishing. Recruitment occurred throughout the year, peaking in June. Production increases in April, June, and October. CPUE ranged from 0.45-0.80 tons/trip, most fish weighed 17-23 kg (38.32%) and fish weighed more than 45 kg <1%. Overall, this condition emphasizes the importance of sustainable management based on periodic data to maintain the sustainability of the tuna population and the fisheries industry. Tuna madidihang (Thunnus albacares) merupakan target utama perikanan tangkap di berbagai perairan tropis, termasuk Indonesia, karena bernilai ekonomi tinggi. Pemintaan pasar global meningkatkan laju eksploitasi, sehingga ukuran layak tangkap tidak diperhatikan. Penurunan stok tuna disebabkan oleh, meningkatnya jumlah unit penangkapan, volume tangkapan yang melebihi batas serta dominasi ukuran tangkapan lebih kecil dari ukuran matang gonad (Lc < Lm), menyebabkan biomassa stok memijah berkurang. Penelitian ini bertujuan untuk mengkaji profil populasi tuna madidihang di perairan Nusa Tenggara Timur (NTT) melalui analisis struktur ukuran, ukuran pertama kali tertangkap (Lc), mortalitas, pola rekrutmen, tren produksi dan Catch Per Unit Effort (CPUE). Data panjang dan berat diperoleh dari I-Fish (Indonesian Fisheries Information System) yang diinisiasi oleh YMDPI. Hasil analisis menunjukan, tuna madidihang yang tertangkap berukuran 78-173 cm, didominasi oleh kelompok ukuran 94-125 cm (82,86 %). Komposisi tangkapan terdiri dari 99,99% ikan dewasa dan 0,01% juvenil. Nilai Lc berisar dari 103,34–106,55 cm, mortalitas penangkapan (F=1,44) lebih tinggi dari mortalitas alami (M = 0,71) dan laju eksploitasi (E) sebesar 0,67, mengindikasikan terjadinya overfishing. Rekrutmen terjadi hampir sepanjang tahun, puncaknya pada bulan Juni. Produksi meningkat pada bulan April, Juni dan Oktober. CPUE berkisar antara 0,45-0,80 ton/trip, sebagian besar ikan berbobot 17-23 kg (38,32%) dan ikan berukuran lebih dari 45 kg < 1%. Secara keseluruhan kondisi ini menegaskan pentingnya pengelolaan berkelanjutan berbasis data periodik untuk menjaga kelestarian populasi dan industri perikanan tuna.
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Mengungkap Aspek Biologi dan Emergence Point Hiu Berjalan Halmahera (Hemiscyllium halmahera) di Laut Pulau Maitara Maluku Utara Indonesia
The Halmahera Walking Shark (Hemiscyllium halmahera) is an endemic marine biota in the Halmahera Sea. This species has a local migration pattern and is territorial. The distribution of this species is in the intertidal area to a depth of 10-15 meters. Previous studies have shown that this species is spread across several islands in the North Maluku Islands. Maitara Island is a small island located between the North Maluku archipelago. The Halmahera Walking Shark species is also found on this island. Information on the Halmahera Walking Shark species is not fully documented. The purpose of the study is related to biological information and emergence points (emergence points) in the Maitara Island Sea. Data collection was carried out on coral reefs, seagrass and mangroves. Samples were captured and morphometric measurements, weight and sex observations were taken. The sea area where the species was found was used to obtain coordinates for the emergence point. An analysis of length-weight relationship data was carried out to see growth patterns. The study found that morphometric measurements varied among individuals, although there were general similarities. Sexes were found in pairs (Male and Female), indicating that proportions and mating were still normal in nature. The habitat of this species is found in the mangrove area, coral reefs, and seagrass, thus describing that there is an association in nature. The emergence point shows that the Halmahera Walking Shark is found along the coast of Maitara Island although the frequency of the number is different. The length-weight relationship found a negative allometric growth pattern. Information on biological aspects and emergence points is important, to be used as a reference for migration areas and habitats for the interests of species, waters, and ecosystem conservation. Hiu Berjalan Halmahera (Hemiscyllium halmahera) merupakan biota laut endemik di laut Halmahera. Spesies ini memiliki pola migrasi lokal dan bersifat teritorial. Penyebaran spesies ini di wilayah intertidal hingga kedalaman 10-15 meter. Penelitian terdahulu menunjukan bahwa spesies ini tersebar di beberapa pulau di Kepulauan Maluku Utara. Pulau Maitara merupakan pulau kecil yang terletak diantara gugusan kepulauan Maluku Utara. Pulau ini juga ditemukan speises Hiu Berjalan Halmahera. Informasi belum terekam lengkap terkait spesies Hiu Berjalan Halmahera. Tujuan penelitian terkait informasi biologi dan emegence point (titik kemunculan) di Laut Pulau Maitara. Pengambilan data dilakukan di terumbu karang, lamun dan mangrove. Sampel ditangkap dan diambil ukuran morfometrik, berat dan pengamatan kelamin. Area laut ditemukannya spesies diambil koordinat untuk di jadikan sebagai titik kemunculan. Analisis data hubungan panjang-berat dilakukan untuk melihat pola pertumbuhan. Hasil penelitian ditemukan ukuran morfometrik bervariasi pada setiap individu, meskipun terdapat kemiripan secara umum. Kelamin ditemukan sepasang (Jantan dan Betina), dengan demikian menunjukan proporsi dan perkawinan masih normal di alam. Habitat tertangkap spesies ini di area mangrove, terumbu karang dan lamun, sehingga mendeskripsikan terdapat asosiasi di alam. Titik kemunculan menunjukan bahwa, Hiu Berjalan Halmahera ditemukan di sepanjang pesisir laut Pulau Maitara meskipun frekuensi jumlah berbeda. Hubungan panjang berat menemukan pola pertumbuhan allometrik negatif. Informasi aspek biologi dan emergence point penting, untuk dapat dijadikan rujukan wilayah migrasi dan habitat untuk kepentingan konservasi spesies, perairan dan ekosistem.
Analisis Kesesuaian Lahan Rehabilitasi Mangrove di Desa Pasar Banggi, Desa Tireman, dan Desa Kabongan Lor, Kecamatan Rembang
Environmental degradation, coastal abrasion, and pollution are strategic issues in Rembang District. Rembang subdistrict, which includes extensive mangrove areas along its coastline particularly in the villages of Pasar Banggi, Tireman, and Kabongan Lor has become increasingly vulnerable to these environmental challenges. This study aims to evaluate land sustainability in these three villages to support future mangrove rehabilitation planning. Fieldwork was conducted in September 2024 across 14 sampling stations. Data collection included assessments of mangrove vegetation by counting individual trees, identifying species, and measuring relevant environmental parameters. Land suitability analysis was carried out by constructing a mangrove land suitability matrix, assigning weights, and calculating scores based on the degree of suitability. Based on land suitability analysis, Pasar Banggi Village was identified as highly suitable for mangrove survival, Tireman Village as suitable, and Kabongan Lor Village as conditionally suitable. Permasalahan degradasi lingkungan, abrasi dan pencemaran menjadi isu strategis yang ada di Kabupaten Rembang. Kecamatan Rembang yang memiliki kawasan mangrove di sepanjang pesisirnya terutama Desa Pasar Banggi, Tireman, dan Kabongan Lor menjadi kawasan yang rentan. Penelitian ini bertujuan untuk mengetahui kesesuaian lahan yang ada di 3 Desa tersebut sehingga dapat digunakan untuk rencana rehabilitasi selanjutnya. Penelitian dilakukan pada Bulan September 2024 dengan total 14 stasiun. Pengambilan data lapangan dilakukan untuk mengetahui kondisi vegetasi mangrove dengan menghitung jumlah individu, jenis, dan pengukuran parameter lingkungan. Analisis kesesuaian lahan dilakukan dengan pembuatan matriks kesesuaian lahan mangrove, penentuan bobot dan perhitungan skor berdasarkan tingkat kesesuaiannya. Berdasarkan kesesuaian lahan mangrove Desa Pasar Banggi menjadi lokasi yang sangat sesuai untuk kelangsungan hidup mangrove, dengan Desa Tireman masuk dalam kategori sesuai dan Desa Kabongan Lor masuk dalam kategori sesuai bersyarat.
Growth Mechanism and Carbon Sequestration of Gracilaria verrucosa
Gracilaria verrucosa, a commercially valuable red macroalga, plays a pivotal role in coastal aquaculture and carbon sequestration. This study investigates the effects of varying initial seedling weights (50 gram, 75 gram, 100 gram, and 125 gram/tie) on biomass yield, specific growth rate (SGR), and carbon sequestration over a 49-day cultivation period. Conducted in a floating raft system under controlled coastal conditions in South Sulawesi, Indonesia, the experiment followed a completely randomized design (CRD) with three replications per treatment. Biomass was harvested at seven-day intervals and assessed for dry weight, growth rate, and carbon composition using standardized methods and elemental analysis protocols. The results indicate that the 125 grams/tie treatment yielded the highest biomass, suggesting that larger initial weights enhance growth through enhanced nutrient uptake. However, the highest SGR and carbon sequestration were recorded in the 50 grams/tie treatment, highlighting the impact of planting density on physiological performance and carbon sequestration. The 100 grams/tie treatment presented the most balanced profile, maintaining high biomass while avoiding significant declines in SGR or carbon sequestration. These findings reveal a critical trade-off between economic and ecological outcomes, with implications for seaweed-based climate mitigation strategies and sustainable aquaculture design. Optimizing planting density can improve both yield and ecosystem services, aligning cultivation strategies with environmental sustainability objectives.
Kelimpahan Gastropoda di Padang Lamun Pulau Menjangan Besar dan Pulau Kemujan, Karimunjawa
Gastropods are a group of fauna commonly found in association with seagrass beds. However, increasing anthropogenic activities have led to significant declines in seagrass ecosystems across Indonesia. The degradation of seagrass has become evident in recent years in the Karimunjawa Islands, particularly at Menjangan Besar Island (due to tourism activities) and Kemujan Island (due to residential and boating activities). This situation is concerning, as it may affect the presence of gastropods inhabiting these areas. This study aims to determine the abundance of gastropods and its relationship with seagrass density at Menjangan Besar and Kemujan Islands. Data collection was carried out in October 2024 using the transect-quadrat method to assess gastropod abundance and seagrass density. Furthermore, correlation and simple linear regression analyses were employed to examine the relationship between gastropod abundance and seagrass density at the study sites. The results indicated that total gastropod abundance at Menjangan Besar Island (10.42 ind/m²) was higher than at Kemujan Island (5.33 ind/m²). Similarly, total seagrass density at Menjangan Besar Island (79.15 ind/m²) was higher compared to Kemujan Island (37.33 ind/m²). The correlation between gastropod abundance and seagrass density at both locations was strong and positive, indicating that seagrass significantly influences gastropods in these ecosystems. Gastropoda merupakan kelompok fauna yang umum ditemukan berasosiasi dengan padang lamun, namun seiring bertambahnya aktivitas antropogenik, padang lamun di Indonesia mengalami banyak penurunan. Penurunan kondisi lamun ini terlihat di beberapa tahun terakhir di Kepulauan Karimunjawa khususnya di Pulau Menjangan Besar (aktivitas pariwisata) dan Pulau Kemujan (aktivitas pemukiman dan kapal warga). Sehingga dikhawatirkan kondisi ini dapat mempengaruhi keberadaan gastropoda yang hidup di dalamnya. Penelitian ini bertujuan untuk mengetahui kelimpahan gastropoda serta hubungannya dengan kerapatan lamun di Pulau Menjangan Besar dan Pulau Kemujan. Pengambilan data dilakukan pada bulan Oktober 2024 di Pulau Menjangan Besar dan Pulau Kemujan menggunakan metode transek kuadran untuk mendapatkan data kelimpahan gastropoda serta kerapatan lamun. Selain itu analisis korelasi sederhana juga digunakan untuk mengetahui hubungan kelimpahan gastropoda dan kerapatan lamun di lokasi penelitian. Hasil kelimpahan total gastropoda di Pulau Menjangan Besar (10,42 Ind/m2) lebih besar dibandingkan nilai kelimpahan Gastropoda di Pulau Kemujan (5,33 Ind/m2). Sedangkan total kerapatan lamun di Pulau Menjangan Besar (79,15 Ind/m2) juga lebih besar dibandingkan dengan total kerapatan lamun di Pulau Kemujan (37,33 Ind/m2). Hubungan antara kelimpahan gastropoda dengan kerapatan lamun di kedua lokasi menunjukkan korelasi kuat dengan nilai positif, sehingga keberadaan lamun sangat mempengaruhi gastropoda yang hidup di dalamnya.
Karakteristik Sedimen Permukaan Dasar Laut Berdasarkan Data Seismik Di Perairan Bengkalis Utara
The northern waters of Bengkalis Island, Riau Archipelago, represent a coastal region vulnerable to abrasion and anthropogenic pressures such as sand mining and marine traffic. This study employs an integrative approach combining seismic reflection methods and grain-size analysis from grab-sampler data to quantitatively assess the characteristics of surface seafloor sediments. Seismic sections from three profiles reveal a relatively flat seabed topography, with depths ranging from 9.5 to 14.9 meters and total sediment layer thickness reaching up to 76.5 meters. Data processing through AGC, FFT, bandpass filtering, and sparse spike deconvolution produced sharp and informative seismic sections, with estimated reflection coefficient values ranging from 0,245 to 0,257. The interpretation results indicate consistency between the reflection coefficients extracted from seismic data and the theoretical values derived from sediment grain sizes of 0,021–0,025 mm, classified as coarse silt. These findings reinforce the effectiveness of hydroacoustic methods in sediment characterization within coastal environments. This approach is considered efficient, broadly spatially covered, and holds strategic potential for shallow marine sedimentology studies. Perairan Bengkalis Utara, Kepulauan Riau, merupakan wilayah pesisir yang rentan terhadap abrasi dan tekanan antropogenik seperti penambangan pasir dan pelayaran. Penelitian ini menggunakan pendekatan integratif antara metode seismik refleksi dan analisis ukuran butir sedimen dari penginti comot (grab sampler) untuk mengkaji karakteristik sedimen permukaan dasar laut secara kuantitatif. Penampang seismik dari tiga lintasan menunjukkan topografi dasar laut yang relatif datar, dengan kedalaman seabed antara 9,5 hingga 14,9 meter dan ketebalan total lapisan sedimen mencapai 76,5 meter. Pengolahan data melalui tahapan AGC, FFT, bandpass filter, dan dekonvolusi menghasilkan visualisasi penampang yang tajam dan informatif, serta estimasi koefisien refleksi dalam kisaran 0,245–0,257. Hasil interpretasi menunjukkan kesesuaian nilai koefisien refleksi dari data seismik dengan nilai teoritis berdasarkan ukuran butir sedimen sebesar 0,021–0,025 mm, yang diklasifikasikan sebagai lanau kasar. Temuan ini memperkuat efektivitas metode hidroakustik dalam karakterisasi sedimen di wilayah pesisir. Pendekatan ini dinilai efisien, luas cakupannya, dan potensial menjadi metode strategis dalam studi sedimentologi laut dangkal.
Struktur Komunitas Ikan Karang di Perairan Kota Sorong, Papua Barat Daya, Indonesia
Reef fish are one of the biota that are sensitive to environmental changes. Their abundance and diversity are supported by good coral reef conditions. This makes them a bioindicator of coral reef conditions. This study aims to examine the diversity of reef fish, ecological indices, and conditions of coral reef benthic substrates in Sorong City waters from September to November 2024 at ten research stations using the Underwater Visual Census (UVC) and Underwater Photo Transect (UPT) methods. The study found 174 species of reef fish from 26 families (107 major, 55 target, and 12 indicator). The diversity (H') and evenness (E) indices were moderate to high at 1.59-3.41 and 0.41-0.89, respectively, and dominance (C) was low at 0.04-0.48. PCA analysis showed that hard coral cover (HC) as the main determinant of reef fish community structure correlated with the families Pomacentridae, Chaetodontidae, Scaridae, Pempheridae, and Blennidae. This finding is important for marine resource management and conservation in the waters of Sorong City. Ikan karang merupakan salah satu biota yang peka dengan perubahan lingkungan. Kelimpahan dan keanekaragamannya didukung oleh kondisi terumbu karang yang baik. Hal ini menjadikannya sebagai bioindikator kondisi terumbu karang. Penelitian ini bertujuan mengkaji keanekaragaman ikan karang, indeks ekologi, dan kondisi substrat bentik terumbu karang di perairan Kota Sorong pada September-November 2024 di sepuluh stasiun penelitian menggunakan metode Underwater Visual Census (UVC) dan Underwater Photo Transect (UPT). Hasil penelitian ditemukan ikan karang 174 spesies dari 26 famili (107 mayor, 55 target, dan 12 indikator). Indeks keanekaragaman (H’) dan keseragaman (E) sedang hingga tinggi 1,59-3,41 dan 0,41-0,89, serta dominasi (C) rendah 0,04-0,48. Analisis PCA menunjukkan tutupan karang keras (HC) sebagai penentu utama struktur komunitas ikan karang berkorelasi dengan Pomacentridae, Chaetodontidae, Scaridae, Pempheridae dan Blennidae. Temuan ini penting untuk pengelolaan sumber daya laut dan konservasi di perairan Kota Sorong.
Mapping of Submarine Geomorphological Structures Using Satellite-Derived Bathymetry and Depth Data in the Waters of Lambasina Island, Kolaka Regency
This research examines the geomorphological characteristics of the seabed around Lambasina Besar and Lambasina Kecil Islands, Kolaka Regency, by integrating Satellite-Derived Bathymetry (SDB) and the Benthic Terrain Modeler (BTM). Depth estimates were derived from Sentinel-2 imagery using the Support Vector Machine (SVM) algorithm and compared with in-situ depth measurements. The validation results indicated a high level of agreement, with R² values ranging from 0.81 to 0.82. The bathymetric data were then processed using Bathymetric Position Index (BPI), slope, and rugosity parameters, which allowed the classification of the seafloor into 13 geomorphological structure classes. The analysis identified various seabed forms, including flat plains, steep slopes, broad slopes, ridges, narrow depressions, and localized basins. These morphological patterns correspond well with coral reef zonation observed in the field. The findings highlight the important role of geomorphological variability in shaping benthic habitats and influencing biodiversity distribution. This approach demonstrates strong potential for supporting marine spatial analysis, conservation planning, and the identification of areas suitable for marine protection. Moreover, the study provides a basis for further research on the relationships between habitat complexity, biomass, coral diversity, and reef-associated fish abundance, which are essential for advancing ecosystem-based coastal management strategies.
Effect of Sea Surface Temperature and Chlorophyll-a On the Catch of Yellowfin Tuna (Thunnus albacares) in The Waters of North Maluku, Indonesia
The waters of North Maluku, abundant in nutrients and ocean currents, provide an ideal habitat for yellowfin tuna (Thunnus albacares), indicating a healthy marine ecosystem. Tuna, an oceanic pelagic species that migrates with ocean currents, is affected by sea surface temperature (SST) and chlorophyll-a plays an important role in determining yellowfin tuna fishing grounds. This study aims to analyze the spatial and temporal distribution of SST and chlorophyll-a concentration in North Maluku waters and analyze the relationship between SST, chlorophyll-a, and tuna catches. The present study employed both descriptive and quantitative analysis methods to examine the relationship between sea surface temperature, chlorophyll-a, and yellowfin tuna catch. The result shows that the temporal fluctuations in the highest recorded SST were seen in the 2021 transitional season, and the lowest in the 2019 East season. Chlorophyll-a concentrations also showed fluctuations, with the highest value recorded in the 2019 East season and the lowest in the 2020 second transitional season. There is an inverse correlation between SST and chlorophyll-a, with low SST tending to be accompanied by high chlorophyll-a concentrations. The decline in chlorophyll-a concentration can be attributed to various factors, including nutrient availability, sunlight intensity, and water temperature. About 17.48% of the catch of yellowfin tuna (Thunnus albacares) in North Maluku waters is influenced by SST and chlorophyll-a while the rest is influenced by other factors. This indicates that other factors play an important role in determining the catch of yellowfin tuna in North Maluku waters.
Bioprospeksi Senyawa Antibakteri dari Bakteri yang Berasosiasi pada Bulu Babi asal Kabupaten Kaur, Bengkulu
The digestive system of sea urchins functions to process organic material from food into bioactive compounds. . However, the direct exploitation of bioactive compounds from sea urchins may trigger ecological imbalances. These bioactive compounds can also be produced through interactions between sea urchins and their diverse associated bacteria within the body. Therefore, alternative methods are needed to obtain bioactive compounds without disrupting the aquatic ecosystem. This study aims to explore bioactive compounds from the associated bacteria of sea urchins (Stomopneustes variolaris Lamarck and Tripneustes ventricosus Lamarck) originating from Kaur Regency, Bengkulu. A total of 30 bacterial isolates were successfully obtained using Zobell Marine Agar (ZMA) medium. Potential isolates were identified through morphological observation, Gram staining, and biochemical tests. Antibacterial activity assays showed that 12 isolates had potential as antibacterial producers based on tests against Bacillus subtilis, Escherichia coli, and Staphylococcus aureus. Two isolates, TVL 6 and TVL 11, were able to inhibit all test bacteria. Additionally, assays using pellets and supernatants showed that all 12 isolates exhibited antibacterial activity, with 5 isolates showing activity in the supernatant. Isolates TVL 6 and TVL 11 were proven effective in inhibiting all test bacteria in both pellet and supernatant forms, with the highest inhibition observed against Staphylococcus aureus. These results indicate that the associated bacteria in the digestive tract of sea urchins have potential as candidates for antibacterial compound producers. Sistem pencernaan bulu babi berfungsi untuk mengolah bahan organik dari makanan menjadi senyawa bioaktif. Namun, eksploitasi senyawa bioaktif dari bulu babi secara langsung dapat memicu ketidakseimbangan ekosistem. Senyawa bioaktif ini juga dapat dihasilkan melalui interaksi antara bulu babi dengan bakteri asosiasi yang beragam di dalam tubuhnya. Oleh karena itu, diperlukan metode alternatif untuk memperoleh senyawa bioaktif tanpa merusak keseimbangan ekosistem perairan. Penelitian ini bertujuan untuk mengeksplorasi senyawa bioaktif dari bakteri asosiasi bulu babi (Stomopneustes variolaris Lamarck dan Tripneustes ventricosus Lamarck) asal Kabupaten Kaur, Bengkulu. Sebanyak 30 isolat bakteri berhasil diisolasi menggunakan media Zobell Marine Agar (ZMA). Identifikasi isolat potensial dilakukan melalui pengamatan morfologi, pewarnaan Gram, dan uji biokimia. Uji aktivitas antibakteri menunjukkan bahwa 12 isolat memiliki potensi sebagai penghasil antibakteri berdasarkan pengujian terhadap kultur uji Bacillus subtilis, Escherichia coli, dan Staphylococcus aureus. Dua isolat, TVL 6 dan TVL 11, mampu menghambat semua bakteri uji tersebut. Selain itu, pengujian menggunakan pelet dan supernatan menunjukkan bahwa 12 isolat mampu menghasilkan aktivitas antibakteri, dengan 5 isolat menunjukkan aktivitas pada supernatan. Isolat TVL 6 dan TVL 11 terbukti efektif menghambat semua bakteri uji baik pada pelet maupun supernatan, dengan penghambatan tertinggi terhadap Stapylococcus aureus. Hasil ini mengindikasikan bahwa bakteri asosiasi dalam saluran cerna bulu babi memiliki potensi sebagai kandidat penghasil antibakteri.
Kesesuaian Habitat Bayi Hiu Karang Sirip Hitam di Taman Nasional Taka Bonerate
Blacktip Reef Sharks (Carcharinus melanopterus) is one of many sharks that are found in Indo-pasific waters and currently listed as vulnerable in IUCN Redlist due to a decrease in population. Habitat suitability and environmental parameters are one of the factors that influence the presence of populations. This research focuses on habitat suitability of Blacktip Reef Sharks pups nursery grounds on the coast of Jinato and Tinabo Besar island, Taka Bonerate National Park with differences in environmental conditions and zone types. Therefore, this research was conducted to analyze the state of environmental parameters at both study site and analyze the influence of parameters and compare the habitat suitability of Blacktip Reef Shark babies at both study site. Data collection was conducted primarily and secondarily in both islands In July and August 2024 and processed using Spearman correlagtion and venn diagram. The number of Blacktip Reef Shark pups on Jinato Island was found to be 3 while on Tinabo Besar Island it was found to be 207, so it is assumed that there is an influence of environmental conditions on the presence of shark pups. There are significant differences and influences on chlorophyll-a, current speed, and salinity parameters, with current being the most influential parameter in the habitat suitability of blacktip reef shark pups on both islands. Tinabo Besar Island has slower current speed conditions, indicating a higher level of habitat suitability. Hiu Karang Sirip Hitam (Carcharinus melanopterus) merupakan salah satu hiu pada area Indo-pasifik yang termasuk kedalam Redlist IUCN dengan kategori vulnerable karena adanya penurunan populasi. Kesesuaian habitat dan parameter lingkungan merupakan salah satu faktor yang memengaruhi keberadaan populasi hiu. Penelitian ini berfokus terhadap kesesuaian habitat bayi Hiu Karang Sirip Hitam di pesisir Pulau Jinato dan Tinabo Besar, Taman Nasional Taka Bonerate dengan perbedaan kondisi lingkungan dan tipe zona yang berbeda. Oleh karena itu, penelitian ini dilakukan untuk menganalisis perbedaan parameter pada kedua pulau, menganalisis pengaruh parameter serta membandingkan kesesuaian habitat bayi Hiu Karang Sirip Hitam pada lokasi kajian. Pengambilan data dilakukan baik secara primer dan sekunder pada kedua pulau di bulan Juli dan Agustus 2024 dan diolah menggunakan uji korelasi Speaman dan diagram venn. Jumlah bayi Hiu Karang Sirip Hitam pada pulau Jinato ditemukan 3 ekor sedangkan pada Pulau Tinabo Besar ditemukan 207 ekor sehingga diasumsikan adanya pengaruh kondisi lingkungan terhadap keberadaan bayi hiu. Terdapat perbedaan dan pengaruh signifikan pada parameter klorofil-a, arus, dan salinitas dengan paremter arus sebagai paremter yang paling berpegaruh dalam kesesuaian habitat bayi Hiu Karang Sirip Hitam di kedua pulau. Pulau Tinabo Besar memiliki kondisi arus yang lebih rendah sehingga menujukkan tingkat kesesuaian habitat yang lebih tinggi.
Kontaminasi Kadmium (Cd) serta Analisis Risiko Kesehatan Manusia melalui Konsumsi Kerang Tahu (Meretrix spp.) di Pesisir Bangkalan
Venus clams are a fishery commodity on the coast of Bangkalan and a source of animal protein for the local people. However, the accumulation of cadmium in these clams could pose a health risk to humans through consumption. Therefore, this study aims to assess the level of cadmium contamination in the environment and analyze the health risks of consuming venus clams on the coast of Bangkalan. Seawater, sediment, and venus clamps samples were taken at two stations (Bancaran and Sambilangan) in the coastal area of Bangkalan, then analyzed for cadmium (Cd) content using Atomic Absorption Spectrophotometry (AAS). The analysis results showed that cadmium in seawater at Bancaran Station (0.003 mg/L) and Sambilangan Station (0.008 mg/L) had exceeded the quality standard threshold. Conversely, the cadmium content in sediment and venus clams at both stations was still below the threshold. Based on Target Hazard Quotients (THQ) and Estimated Weekly Intakes (EWI), consumption of tofu clams from both stations did not pose a health risk. Kerang tahu banyak dimanfaatkan sebagai komoditas perikanan di pesisir Bangkalan dan menjadi salah satu sumber protein hewani bagi masyarakat setempat. Namun, akumulasi kadmium dalam kerang tersebut dapat menimbulkan risiko kesehatan bagi manusia melalui konsumsi. Oleh karena itu penelitian ini bertujuan untuk menilai tingkat cemaran kadmium pada lingkungan serta menganalisis risiko kesehatan dari konsumsi kerang tahu di Pesisir Bangkalan. Pengambilan sampel air laut, sedimen dan kerang laut dilakukan di dua stasiun (Bancaran dan Sambilangan) di lingkup pesisir Bangkalan, kemudian dilakukan analisis kandungan cadmium (Cd) dengan menggunakan alat Atomic Absorption Spectrophotometry (AAS). Hasil analisis menunjukkan kadmium pada air laut di Stasiun Bancaran (0,003 mg/L) dan Sambilangan (0,008 mg/L) telah melebihi ambang batas baku mutu. Sebaliknya kandungan kadmium di sedimen dan kerang tahu pada kedua stasiun masih dibawah ambang batas. Berdasarkan Target Hazard Quotients (THQ)dan Estiamted Weekly Intakes (EWI), konsumsi kerang tahu di kedua stasiun tidak berisiko terhadap kesehatan.
Skrining Fitokimia dan Evaluasi Antioksidan serta Antibakteri Ekstrak Mangrove Asal Pantai Lampu Satu
The mangrove ecosystem is characterized by high biodiversity and the production of various secondary metabolites with potential bioactive properties, making it a promising source of natural cosmetic ingredients. Phytochemical screening was carried out to detect the present of tannins, saponins, steroids, alkaloids, and flavonoids. Antibacterial activity was evaluated using disc diffusion method, while antioxidant activity was assessed through the DPPH assay. Seven species were identified in this study, namely Exoecaria agallocha, Laguncularia racemosa, Nypa fructicans, Bruguiera cylindrical, Amyema anisomeres, Ipomoea pes-caprae, and Acrostichum aureum. Phytochemical analysis revealed that saponins and tannins were present in most species, whereas alkaloids and flavonoids were specific to certain taxa. None of the tested extracts exhibited antibacterial activity against Eschericia coli. Antioxidant evaluation showed that Acrostichum aureum exhibited very strong activity (IC50 = 38,3 ppm), while Ipomoea pes-caprae and Laguncularia racemosa demonstrated strong antioxidant potential, and the remaining species ranged from weak to very weak activity. These findings indicate considerable variation in secondary metabolite composition and antioxidant capacity among mangrove species from Merauke, and suggest that Acrostichum aureum could serve as a promising natural source of antioxidants for the development of plant-based cosmetic formulations. Ekosistem mangrove memiliki keanekaragaman hayati tinggi dan menghasilkan berbagai metabolit sekunder dengan potensi bioaktif, menjadikannya sumber yang menjanjikan untuk bahan kosmetik alami. Uji fitokimia yang dilakukan adalah uji tanin, saponin, steroid, alkaloid dan flavonoid. Uji antibakteri dilakukan dengan metode difusi cakram serta uji antioksidan dengan metode DPPH. Hasil penelitian menunjukkan bahwa 7 spesies yang teridentifikasi meliputi Excoecaria agallocha, Laguncularia racemosa, Nypa fruticans, Bruguiera cylindrica, Amyema anisomeres, Ipomoea pes-caprae, dan Acrostichum aureum. Analisis fitokimia memperlihatkan bahwa saponin dan tanin banyak ditemukan pada sebagian besar spesies, sedangkan alkaloid dan flavonoid bersifat spesifik pada jenis tertentu. Seluruh spesies yang diuji tidak menunjukkan aktivitas antibakteri terhadap E. coli. Evaluasi antioksidan menunjukkan bahwa Acrostichum aureum memiliki aktivitas sangat kuat (IC₅₀ = 38,3 ppm), sementara Ipomoea pes-caprae dan Laguncularia racemosa menunjukkan aktivitas antioksidan kuat, dan spesies lainnya berkisar dari lemah hingga sangat lemah. Hasil ini menunjukkan adanya variasi kandungan metabolit sekunder dan kapasitas antioksidan antarspesies mangrove asal Merauke, serta mengindikasikan bahwa Acrostichum aureum berpotensi menjadi sumber antioksidan alami untuk pengembangan kosmetik berbasis bahan alam.
Penyemaian Generatif Enhalus acoroides melalui Variasi Wadah dan Substrat: Kajian Laju Pertumbuhan, Kelulushidupan, dan Parameter Perairan
Seagrass is a higher plant that lives in shallow marine waters and plays an important role in tropical coastal ecosystems. Seagrass has the ability to reproduce in two ways, namely vegetatively and generatively. Enhalus acoroides is one of the species widely distributed in Indonesian tropical waters and can bear fruit throughout the year, but the survival rate of seedlings in nature tends to be low due to high environmental variability. Based on this, controlled generative sowing is an effective alternative in helping seedlings through the early stages of growth. This study aims to determine the effect of container and substrate variations, as well as their interaction, on the growth rate and survival rate of E. acoroides generative seedlings. The study results showed that substrate type had a significant effect on seedling growth rate (p = 0.004), whereas container type did not have a significant effect (p = 0.558). The interaction between container and substrate was also significant (p = 0.042). Seedlings grown in muddy sand exhibited a higher growth rate compared to those in sand. The survival rate across all treatment combinations was 100%, indicating that the different growing media were capable of optimally supporting the initial growth phase. These findings emphasize the importance of selecting an appropriate substrate to enhance the growth rate of seagrass seedlings. Lamun merupakan tumbuhan tingkat tinggi yang hidup di perairan laut dangkal dan berperan penting dalam ekosistem pesisir tropis. Lamun memiliki kemampuan untuk bereproduksi melalui dua cara, yaitu vegetatif dan generatif. Lamun Enhalus acoroides merupakan salah satu spesies yang tersebar luas di perairan tropis Indonesia dan dapat berbuah sepanjang tahun, namun tingkat kelulushidupan bibit di alam cenderung rendah akibat tingginya variabilitas faktor lingkungan. Berdasarkan hal tersebut, penyemaian generatif secara terkontrol menjadi alternatif yang efektif dalam membantu bibit melewati fase awal pertumbuhan. Penelitian ini bertujuan untuk mengetahui pengaruh variasi wadah dan substrat, serta interaksi keduanya terhadap laju pertumbuhan dan kelulushidupan semaian generatif E. acoroides. Hasil penelitian menunjukkan bahwa jenis substrat berpengaruh signifikan terhadap laju pertumbuhan bibit (p = 0,004), namun jenis wadah tidak memberikan efek yang signifikan (p = 0,558). Interaksi wadah dengan substrat memberikan pengaruh yang berarti (p = 0,042). Substrat pasir berlumpur menghasilkan laju pertumbuhan yang lebih tinggi dibandingkan substrat pasir. Tingkat kelulushidupan seluruh kombinasi mendapat nilai sebesar 100%, mengindikasikan bahwa variasi media tanam tetap mampu mendukung fase awal pertumbuhan secara optimal. Temuan ini menegaskan bahwa pemilihan substrat yang tepat diperlukan untuk meningkatkan laju pertumbuhan bibit lamun.
Estimasi Cadangan Karbon Mangrove Menggunakan Citra Sentinel-2A di Desa Banjarsari Pulau Enggano
Global climate change remains one of the major challenges of the 21st century, and mangrove ecosystems play a crucial role as blue carbon sinks, helping mitigate greenhouse gas emissions. However, data on mangrove carbon stocks in Indonesia’s outermost islands, such as Enggano Island, are still limited. This study aims to estimate the aboveground carbon stock of mangrove forests in Banjarsari Village, Enggano District, by integrating field measurements and Sentinel-2A imagery. Biomass was calculated using an allometric approach, while spatial carbon estimation was derived from the Normalized Difference Vegetation Index (NDVI). The results show that the mangrove area covers approximately 193,25 ha, dominated by dense vegetation (98%) with NDVI values ranging from −0.5 to 0.94. The dominant species were Rhizophora apiculata. The total above-ground carbon stock was estimated at 44,276.78 tons C. The regression between NDVI and carbon stock produced the equation y = 2.1402x − 185.36, with a coefficient of determination (R²) of 0.48 and an RMSE of 161,14 tons/ha. These findings demonstrate the significant carbon storage capacity of Enggano’s mangrove ecosystem and highlight its crucial role in supporting climate change mitigation and low-carbon development in Indonesia’s remote coastal regions. Perubahan iklim global menjadi tantangan utama abad ini, dan ekosistem mangrove berperan penting sebagai penyerap karbon biru (blue carbon) yang efektif dalam menekan emisi gas rumah kaca. Namun, informasi mengenai stok karbon mangrove di wilayah kepulauan terluar Indonesia, seperti Pulau Enggano, masih sangat terbatas. Penelitian ini bertujuan mengestimasi cadangan karbon mangrove bagian atas di Desa Banjarsari, Kecamatan Enggano, melalui integrasi data lapangan dan citra Sentinel-2A. Biomassa dihitung menggunakan pendekatan alometrik, sedangkan estimasi spasial karbon diperoleh melalui analisis indeks vegetasi NDVI. Hasil penelitian menunjukkan bahwa luas ekosistem mangrove mencapai 193,25 ha dengan dominasi kerapatan rapat (98%) dan nilai NDVI berkisar antara −0,5 hingga 0,94. Spesies dominan yang ditemukan adalah Rhizophora apiculata. Total cadangan karbon diperkirakan mencapai 44.276,78 ton C. Hubungan antara NDVI dan stok karbon menunjukkan persamaan regresi y = 2,1402x − 185,36 dengan koefisien determinasi (R²) sebesar 0,48 dan RMSE 161,14 ton/ha. Hasil ini menegaskan bahwa ekosistem mangrove Enggano memiliki potensi besar sebagai penyerap karbon, sekaligus berkontribusi terhadap upaya mitigasi perubahan iklim dan kebijakan pembangunan rendah karbon di wilayah pesisir terpencil Indonesia.