Density and ecological index of nudibranch in Humbolt Bay Water Jayapura City Papua Province, Indonesia

Nudibranchs are marine invertebrates from the mollusc phylum of the gastropod class subclass Opisthobranchiata. Nudribanch has many benefits because of its compound content, has the beauty of attractive colors as an underwater tourism photo object, and can be used as biota indicators of ecosystem health. The purpose of this research is to assess density, diversity index, Evenness index, and dominance index as well as water parameters that support the growth and development of nudibranchs in Humbolt Bay, Jayapura City. The research method used is the Underwater Visual Census (UVC) method at a depth of 5 m and 10 m with an observation width of 2.5 to the right and to the left along 100 m. The results showed that there were 14 types of nudibranchia with 122 individuals, with the dominant species being Phyllidiella pustulosa and Phyllidia varicosa. The density of the nudibranch is quite low, which is around 0.022-0.036 individuals / m2, the Diversity Index is low, which is around 1.228-1.463, the Uniformity Index is classified as a small population, 0.120-0.260 (close to 0), and the Dominance Index is quite stable, namely 0.270-0.402. Based on water parameter data It was found that the waters and habitats in Jayapura City's Humbolt Bay are under pressure as indicated by the decline in the quality of the ecosystem, but are still in normal conditions that support the growth and development of marine life, especially nudibranchs.

Macrozoobenthos Community Structure and its Relationship with Waters Quality of Kampung Baru, Sebong Lagoi Village, Bintan Regency

Kampung Baru is an area on Bintan Island which is located in Sebong Lagoi Village, Teluk Sebong District, Bintan Regency, Riau Islands Province. This study aimed at determine the structure of the macrozoobenthos community, the condition of the physico-chemical parameters of the waters and the relationship between macrozoobenthos and water quality. This research was conducted using a survey method. Sampling site points of this study using random sampling method with 30 sampling site points at high and low tide. The parameters measured are physical, chemical and biological parameters of the water. The results showed that there were 18 species of macrozoobenthos consisting of 4 classes of macrozoobenthos and 3 phylum at 30 sampling site points, namely mollusca, annelida, and arthhopoda phylum. Based on the ecological index value, it is known that the macrozoobenthos species in Kampung Baru waters are still classified as low with disproportionate conditions. The values ​​of diversity index (low), uniformity index (high) and dominance index (low). Water quality of Kampung Baru waters at high tide still meet quality standards of Kepmen-LH No. 51 of 2004, but at low tide the values ​​of temperature, DO, and salinity parameters did not meet quality standards. The relationship between macrozoobenthos parameters and water quality using PCA analysis where density parameters have a relationship with two parameters, namely temperature and pH.

Length-Weight Relationship and Condition Factor of Layang Fish (Decapterus russelli) Landed at Tenda Fish Landing Base, Gorontalo

The study aims to figure out growth pattern and condition factor of the flying fish (Decapterus russelli) landed at the Fish Landing Base Tenda, Hulonthalangi District, Gorontalo City. Sampling of 360 layang fish was carried out randomly based on a simple random sampling method for three months. Determination of fish sex was conducted visually by dissecting samples and observing the gonads. The study showed that the layang fish (D. russelli) landed in PPI Tenda had a positive allometric growth pattern with condition factor values ranging from 1.005 to 1.014 and 1.002 to 1.620 for male and female, respectively

Coral Cover and Diversity Life form in Different Geomorpholgy Zone at Kampung Baru Waters, Bintan Island

The purpose of this study was to compare the percentage of cover conditions, diversity index, uniformited index and dominance index of life form coralin the zones reef flate and reef slope in Kampung Baru Lagoi, Bintan Regency. This research was conducted using the method Line Intersept Transect (LIT) with the line transect length used was 30 meters, three replications with a gap of 5 meters. The results showed, at point station 1 in the zone flate Reef the percentage of live coral cover was 36,92% are categorized as moderate. Forms the coral growth Life form were found as many 9 types of Life form hard corals namely ACB, ACT, ACE, ACS, ACD, CB, CM, CE, CS with a diversity index of 2,53 are categorized as moderate, a uniformited index of 0,80 are categorized as high, and a dominance index of 0,22 are categorized as low. At the point station 2 in the zone slope Reef the percentage of live coral cover was 50,44% are categorized as good. Forms of coral growth (Life form) were found as many as 8 types of Life form hard corals namely ACT, ACE, CB, CM, CE, CS, CF and CMR, with a diversity index of 2,13 are categorized as moderate, a uniformited index of 0,71 are categorized as high, and a dominance index of 0,30 are categorized as low.

Pendugaan Status Sumberdaya Perikanan Skala Kecil di Kota Semarang

Perikanan di Kota Semarang didominasi oleh perikanan skala kecil. Hal ini ditandai dengan penggunaan armada perikanan paling besar 10 gros ton yang beroperasi di dekat pantai. Data statistik perikanan selama 10 tahun (2010-2019) terlihat hasil tangkapan yang mulai menurun, sementara perkembangan jumlah unit penangkapan yang semakin meningkat. Hal ini mengindikasikan stok ikan mulai berkurang dan tingkat pemanfaatan sumberdaya perikanan mengarah overfishing. Hal tersebut diperkuat dengan hasil pengamatan langsung di lapangan yang menunjukkan jumlah hasil tangkapan cenderung sedikit dan ukuran ikan yang tertangkap cenderung kecil. Tujuan penelitian ini adalah menganalisis status sumberdaya perikanan skala kecil di Kota Semarang. Metode yang dipakai dalam penelitian ini adalah analisis data runtun waktu (time series) produksi surplus yaitu data dari hasil tangkapan (ton/tahun) dan jumlah alat tangkap (unit), dalam kurun waktu 10 tahun (2010-2019), untuk menghitung nilai catch per-unit effort (CPUE), potensi maksimum lestari (MSY), jumlah effort optimum (fopt), tingkat pemanfaatan (TP) dan tingkat kapasitas (TK). Penelitian ini diperoleh hasil adanya tren penurunan CPUE; hasil tangkapan/produksi perikanan eksisting tahun 2019 telah melewati nilai MSY-nya yaitu sebesar 479 ton/tahun (Schaefer) dan 439,11 ton/tahun (Fox); tingkat pemanfaatan lebih dari 100% yaitu sebesar 108-127% (Schaefer) dan 118-138% (Fox), sehingga perikanan skala kecil di Kota Semarang berada pada tingkat over-exploited. Berdasarkan analisis fopt menunjukkan jumlah alat tangkap yang digunakan (fexisting) telah melebihi jumlah optimumnya dengan tingkat kapasitas penangkapan melebihi 100%, sehingga perikanan skala kecil di Kota Semarang telah mengalami kelebihan kapasitas penangkapan (overcapacity).

Identifikasi Dan Prevalensi Ektoparasit Ikan Kerapu Lumpur (Epinephelus tauvina) Pada Keramba Jaring Apung Di Kuala Langsa

Greasy grouper (Epinephelus tauvina) is one type of marine fish that has economic value and can be developed into a promising cultivation commodity. The purpose of this research is to find Types of parasites and prevalence rates of ectoparasite in Greasy grouper (Epinephelus tauvina) on floating net cages in Kuala Langsa. The research method was conducted using a survey method. Sample taken by purposive sampling, amounting to 20 Greasy grouper (Epinephelus tauvina) with a size of 20-25cm and were observed at Laboratory Faculty of Agriculture, Samudra University. Fish body organs were observed including all parts of the fins, mucus, gills, then identification using microscopic and macroscopic methods. The results obtained were ectoparasites infecting Greasy grouper (Epinephelus tauvina) only one species from the genus Dactylogyrus which was found mostly in floating net cages cultivation in Kuala Langsa. These ectoparasite were found in the gill lamella Greasy grouper (Epinephelus tauvina), with the overall sample prevalence rate at 50% and the attack rate classified as “very frequent”.

Tingkat Kerusakan Mangrove pada Desa Jatimalang, Jatikontal dan Ngentak di Pesisir Kabupaten Purworejo, Jawa Tengah

Hutan mangrove merupakan organisme atau tumbuhan yang mampu hidup pada salinitas yang relatif tinggi dan umumnya terdapat di seluruh pantai serta tumbuh berkembang pada daerah yang mempunyai pasang surut air laut. Penelitian bertujuan mengetahui kondisi ekosistem mangrove di Pesisir Selatan Purworejo. Dilaksanakan dari bulan Maret sampai dengan bulan April berlokasi di tiga desa yang berada di Kecamatan Purwodadi, Kabupaten Purworejo, Jawa Tengah. Metode yang digunakan untuk pengambilan data adalah Metode Transek Garis dan Petak Contoh (Transect line plot). Hasil pengamatan ditemukan 3 jenis mangrove, yang ditemukan pada lokasi, yaitu: Rhizophora mucronata, Sonneratia alba dan Avicennia alba, terdapat juga mangrove Acanthus ilicifolius, dan Nhypa fruticans, diketahui juga kerapatan mangrove tertinggi pada stasiun III 9900 Ind/Ha, tutupan jenis Sonneratia alba 50.48, frekuensi tertinggi pada jenis mangrove Sonneratia alba dan Rhizophora mucronata. Indeks nilai penting tingkat pohon, pancang, dan semai yaitu tingkat pohon dari Sonneratia alba sebesar 215, tingkat pancang dari jenis Sonneratia alba sebesar 142, dan semai untuk Rhizophora mucronata dan Sonneratia alba sebesar 100.

Status Perikanan Tangkap di Sungai Sebangau dan Sungai Katingan, Taman Nasional Sebangau Kalimantan Tengah

Sebangau dan Katingan sebagian alirannya menjadi batas terluar dari kawasan konservasi Taman Nasional Sebangau (TNS) Kalimantan Tengah. Kedua sungai mendapat pengaruh langsung dari hutan rawa gambut dan menghasilkan karakteristik perairan hitam. Sungai memiliki sumberdaya ikan yang dimanfaatkan melalui kegiatan perikanan tangkap oleh masyarakat sungai, yakni nelayan. Kegiatan penangkapan berlangsung di wilayah induk dan anak sungai sebagai wilayah komunal dan terkontrol. Wilayah penangkapan mempengaruhi kondisi perikanan tangkap, hal ini menjadi permasalahan dalam penelitian ini. Tujuan penelitian ini adalah menguraikan pelaku usaha perikanan, identitas penangkapan, hasil tangkapan, dan wilayah penangkapan. Lokasi penelitian bertempat di induk dan anak Sungai Sebangau dan Katingan, berlangsung dari bulan Oktober hingga Desember 2019. Metode penelitian menggunakan metode deskriptif melalui pendekatan kualitatif. Pengumpulan data primer yaitu observasi, wawancara, dan dokumentasi, data sekunder melalui studi dokumen dari berbagi sumber. Tahapan analisis data terdiri atas tiga tahap yaitu reduksi data, penyajian data, dan penarikan kesimpulan. Hasil penelitian yang dapat adalah usaha perikanan tangkap dilakukan oleh nelayan dengan alat tangkap tradisional. Nelayan memiliki hasil tangkapan berupa ikan konsumsi air tawar yang terdiri dari delapan jenis famili ikan per sungai. Nelayan melakukan penangkapan di bagian induk dan anak sungai. Wilayah penangkapan terdiri atas dua wilayah, yakni wilayah komunal menempati induk Sungai Sebangau dan seluruh wilayah Sungai Katingan dan wilayah terkontrol berlokasi di anak Sungai Sebangau. Wilayah komunal bersifat terbuka sedangkan wilayah terkontrol bersifat tertutup, hal ini mempengaruhi kondisi perikanan yang berlangsung di setiap wilayah.

Kerentanan Bycatch Tuna Dari Perikanan Handline di Selatan Samdera Hindia: Pencatatan Pelabuhan Sendang Biru-Malang

Bycatch tuna merupakan komoditas ikan komersial penting dalam perikanan tuna Samudera Hindia. Aktivitas penangkapan bycatch tuna juga berdampak pada penurunan stok sehingga menjadi rentan dan potensial tidak berkelanjutan. Penelitian ini dilakukan di Sendangbiru Malang pada Bulan Juli 2013. Analisis kerentanan dengan pendekatan jarak Euclidean dengan data produkitivitas dan susceptabilitas menggunakan software PSA NOAA. Hasil tangkap bycacth tuna adalah ikan cakalang (Katsuwonus pelamis), Ikan lemadang (Coryphaena hippurus), baby tuna (Thunnus albacores). Hasil kerentana menunjukan tingkat kerentanan yang diperoleh sebesar 1,66 untuk baby tuna, 1,27 untuk lemadang dan 1,42 untuk cakalang. Secara keseluruhan nilai indek kerentanan masih rendah dari 1,8 dimana stok tergolong rentan rendah dan potensi ikan bycatch tuna masih berpotensi berkelanjutan di Sendang Biru.

Diversitas Komunitas Fitoplankton Di Danau Hias Gold Coast, Pantai Indah Kapuk-Jakarta

The Gold Coast ornamental lake at Pantai Indah Kapuk, Jakarta is artificial, shallow and not too wide. It receives runoff from residential drainage channels, that affects the trophic states of the waters and the phytoplankton that live in it. This study aims to analyze the diversity of phytoplankton communities temporally related to trophic states in these waters. Sampling was carried out monthly for one year on the physical and chemical parameters of the waters and phytoplankton. Furthermore, the analysis of community structure and diversity of, a, b, and g, as well as determining the level of trophic states using the Chlorophyceae index and Cyanophyceae index. During the observation, four classes of phytoplankton were obtained, Chlorophyceae, Bacillariophyceae, Cyanophyceae, and Euglenophyceae which in total consisted of 41 species (g), a1-12 totaling 20-28 species, and b which were relatively small. The value of diversity index (H ') is low, the evenness (E) is moderate, and the dominance (C) is low. The values ​​of the two trophic states indices indicated that the waters were in a eutrophic condition during the observation. In general, it can be concluded that the conditions of the waters were always eutrophic for one year, the diversity of phytoplankton is relatively low and did not show significant changes in species between observations.