Coral reef ecosystem is known as an important place to live various types of fish, where coral conditions will affect the diversity and abundance of the fish. In healthy coral reef ecosystems generally can be found many types of fish with high density. This research aims to investigate the diversity and abundance of coral fishes at Saebus Island, East Java. The observation conducted at 4 stations, according to cardinal point by UVS (underwater visual census) methods with belt transect with the visibility of 2,5 m horizontally, and 5 m vertically. The length of transect was 100 m parallel with coastline, with the area of observation is 500 m2. The censuses were conducted at 2 different depths (3 and 10 m). This study found 70 kinds of coral fish originated form 20 family at all stations. These fishes were from 3 different fish categories i.e. 7 target fishes, 13 indicator fishes, and 50 major fishes. Three different fishes that dominated target fish, indicator fish and major fish were Epinephelus fasciatus, Chaetodon baronessa and Aulostomus chinensis, respectively. There was similar value of fish diversity index at two different depths which were 3.635 and 3,623. While uniformity index at the depth of 3m was 0.153 and at 10m was 0.217, and domination index at the depth of 3m was 0.11 and at 10m was 0.167. These values suggest that diversity of coral fish at Saebus island can be categorized as high diversity.

Abstract. Indonesian government currently has policies to improve the performance of the tourism sector, including marine tourism. One of the attractions of marine tourism is the coral ecosystem especially through scuba diving activities. The purpose of this study was to determine the suitability of the coral ecosystem on Saebus Island, East Java, to find appropriate locations for scuba diving activities. Purposive samplings were done around the island to determine four stations which will be assessed through suitability analysis. Tourism Suitability Index was used to assess all stations for scuba diving activities. The result showed that all four stations were categorized as very suitable with the score: 85%, 85%, 85% and 83%, respectively. Several aspects that need to be improved and anticipated for diving at all stations are coral coverage and water current. These results suggest that there are several spots around Saebus Island that are suitable for diving site, and can be promoted as marine tourism destination.

Selat Makassar merupakan salah satu celah penghubung antara Samudera Pasifik dan Samudera Hindia dengan karakteristik oseanografi lebih dipengaruhi oleh Samudera Pasifik melalui sirkulasi Arlindo. Sirkulasi Arlindo bersama dengan variasi pergerakan angin muson akan berpengaruh terhadap distribusi suhu, salinitas dan densitas di lapisan homogen dan termoklin. Penelitian ini bertujuan mengkaji distribusi suhu, salinitas dan densitas di lapisan homogen dan termoklin perairan Selat Makassar. Penelitian ini dilaksanakan pada bulan Oktober 2015. Data diperoleh dari Pusat Penelitian dan Pengembangan Sumber Daya Laut dan Pesisir (P3SDLP) dengan data primer berupa data suhu, salinitas, densitas dan kedalaman menggunakan instrumen CTD. Stasiun pengambilan data terdiri dari 18 stasiun pengambilan data berdasarkan metode purposive sampling. Data yang diperoleh kemudian dianalisis menggunakan metode analisis statistik deskriptif. Hasil menunjukkan bahwa ketebalan lapisan homogen antara 19,5-68,5 m. Ketebalan lapisan termoklin bervariasi antara 50-220 m. Variabilitas ketebalan lapisan homogen dan lapisan termoklin disebabkan beberapa  faktor seperti tekanan angin, pemanasan matahari, transpor massa air, dan aktivitas gelombang internal.  Sebaran nilai suhu di lapisan homogen bervariasi antara 25,35-29,94 oC. Suhu permukaan laut cenderung lebih tinggi di bagian utara Selat Makassar. Suhu di lapisan termoklin berkisar antara 12,09-29,22 oC. Salinitas di lapisan homogen bervariasi antara 33,91-34,59 ‰. Nilai salinitas permukaan laut cenderung lebih tinggi di selatan Selat Makassar. Hal ini diduga disebabkan pengaruh dari Laut Jawa dan Laut Flores. Salinitas di lapisan termoklin bervariasi antara 34,18-34,88 ‰. Nilai densitas di lapisan homogen bervariasi antara 20,93-22,93 kg/m3. Nilai densitas di lapisan termoklin bervariasi antara 21,47-26,13 kg/m3. Gradien rata – rata temperatur lapisan termoklin antara 0,07-0,14 oC/m. Gradien rata – rata temperatur berbanding terbalik dengan ketebalan lapisan termoklin. Makassar Strait is a pathway that connected the Pacific Ocean and the Indian Ocean with oceanographic characteristics  more influenced by the Pacific Ocean through Arlindo. Arlindo circulation and movement variations of the monsoon will affect the distribution of temperature, salinity and density in homogeneous and thermocline layer. The aims of this study is were to assess the distribution of temperature, salinity and density in homogeneous and thermocline layer of Makassar Strait. This research was conducted in October 2015. Data were obtained from the Pusat Penelitian dan Pengembangan Sumber Daya Laut dan Pesisir (P3SDLP) with the primary data that were temperature, salinity, density and depth by using CTD instruments. Data measurement station consists of 18 stations based on purposive sampling method. Data were analyzed using descriptive statistical analysis method. The results showed that the homogeneous layer thickness were vary with range from 19.5 m to 68.5 m. Thermocline layer thickness between 50-220 m. Variability homogeneous layer thickness and the thermocline were caused by several factors such as air pressure, solar heating, water mass transport, and internal wave activity. The distribution of temperature in a homogeneous layer were vary with range from 25.35 ° C to 29.94 ° C. Sea-surface temperatures tend to be higher in the northern of Makassar Strait. Temperatures in the thermocline layer ranged from 12.09 °C to 29.22 °C. Salinity in a homogeneous layer werer vary with range from 33.91 ‰ to 34.59 ‰. Sea surface salinity were higher in the southern of Makassar Strait. This was assumed due to the influence of the Java Sea and Flores Sea. Salinity in the thermocline layer were vary with range from 34.18 ‰ to 34.88 ‰. The density in a homogeneous layer vary among 20.93-22.93 kg/m3. The density in the thermocline layer were vary with range from 21.47 kg/m3 to 26.13 kg/m3. Average gradient temperature of the thermocline layer were vary with range from 0.07 °C/m  to 0.14 °C/m. Average gradient of temperature was inversely proportional to the thickness of the thermocline layer.

Pulau Panjang terletak di sebelah barat pantai Kota Jepara memiliki luas wilayah teritorial 30 Ha dan dimanfaatan sebagai wisata pulau, wisata ziarah, dan lokasi penangkapan ikan. Kombinasi kondisi gelombang ekstrim dan air pasang mengakibatkan tekanan kuat di pesisir Pulau Panjang sehingga menimbulkan kerusakan pada fasilitas wisata. Berdasarkan hal tersebut, diperlukan adanya analisis mengenai karakteristik penjalaran gelombang laut untuk menunjang segala jenis kegiatan masyarakat. Analisis penjalaran gelombang dilakukan melalui pendekatan pemodelan numerik hidrodinamika dua dimensi (two-dimensional hydrodynamic model). Data primer yang digunakan adalah data pengukuran langsung nilai gelombang menggunakan instrument Acoustic Doppler Current Profiler dan pengukuran langsung data batimetri menggunakan instrument single-beam echosounder. Data sekunder meliputi data angin (1999 – 2019) yang didapatkan dari portal unduh data di www.ogimet.com, data pasang surut BMKG dan data batimetri dari Badan Informasi Geospasial. Tinggi gelombang signifikan (Hs) dan periode signifikan (Ts) didapatkan dari konversi data angin menjadi nilai Hs dan Ts dengan metode DNS. Nilai Hs dan Ts maksimal setiap arah mata angin mmenjadi input perhitungan model hidrdodinamika. Hasil spasial penjalaran gelombang tertinggi terjadi pada arah datang gelombang dari arah timur laut, tenggara dan barat.  Penjalaran gelombang di Pulau Panjang menciptakan daerah terlindung di sisi seberang dari arah datang gelombang dan saat gelombang endekati pantai penjalaran gelombang mengikuti kontur garis pantai diikuti dengan melemahnya kecepatan rambat gelombang. Panjang Island is located on the west coast of Jepara City and has a territorial area of 30 hectares and is used as island tourism, pilgrimage tours, and fishing locations. The combination of extreme wave conditions and high tide resulted in strong force on the coast of Panjang Island causing damage to tourist facilities. Based on this, it is necessary to have an characteristics analysis of the sea waves propagation to support all types of community activities. Analysis of the propagation of the waves was carried out using a two-dimensional hydrodynamic model approach. The primary data used are direct measurement data of wave values using the Acoustic Doppler Current Profiler instrument and direct measurement of bathymetric data using a single-beam echosounder instrument. Secondary data includes wind data (1999 - 2019) obtained from the data download portal at www.ogimet.com, BMKG tidal data and bathymetry data from the Geospatial Information Agency. Significant wave height (Hs) and significant period (Ts) are obtained from the conversion of wind data into Hs and Ts values using the DNS method. The maximum Hs and Ts values for each cardinal direction are the input for calculating the hydrodynamic model. The highest spatial results of wave propagation occur in the coming direction of waves from the northeast, southeast and west. The wave propagation in Panjang Island creates a protected area on the opposite side from the direction of the waves coming and when the waves approach the coast the propagation of the waves follow the contours of the coastline followed by a weakening of the wave propagation speed.

The implementation of KKN is one of the obligations of students to fulfil the tri dharma of higher education in the community, but the condition of Level 4 regional restrictions and internet conditions that have not been established in the service area forced us to carry out Hybrid KKN with the main assumption of stopping the spread of covid in the Central Kalimantan region, building cooperation between government, between universities and at the same time make KKN produce measurable outputs and have an impact on society. Various policies that emerged during the covid pandemic forced students to be creative and innovative in community service in Mawar Mekar village. This article attempts to prove that a hybrid community service process by minimizing risk is possible in rural areas with a minimum internet signal

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