This study was conducted from November 2017 in Rupat Strait, Riau Province. The analysis of model was done in Laboratorium of Physical Oceanography, Departement of Marine Science, Faculty of Fisheries and Marine, University of Riau. The research aims to understand the wave and tidal current on high tide (spring tide condition) in Rupat Strait. The significant wave height is about 0.12-0.90 m/s. The current speed is about 0.18-0.78 m/s. The result of the study indicate that at spring tide condition, the tidal current from Malaka Strait flows up to Rupat Strait by northern and eastern part of Rupat Strait. This condition influences distribution of sediments in Rupat Strait the cause of the changes coastline

The dynamics of climate conditions occur as a result of national development to have an impact on the condition of the atmosphere and ocean environment. This condition causes a change of coral reef fish live, as much as 50% of reef fishes die when extreme temperatures occur in Australia. Research related to changes in temperature and carbon dioxide conditions becomes very important to see changes in coral reef fish conditions. Several previous studies about impact of climate change to coral reef fish used many species of coral reef fishes in different location have shown a significant change in morphology, genetic, and behavior of reef fishes when there are changes in environmental conditions. Morphological results showed a decrease in length and weight of coral reef fish; genetic result showed an upregulated and downregulated function of genetic in coral reef fish.

Dunaliella salina is a group of green algae that produces pigment (chlorophyll and carotenoids) and used as live feed in hatchery especially for marine commodities. Nitrogen and phosphorus are needed by D. salina can be obtained from P. radiatus fertilizer. The purpose of this research is to know the effect and optimal dose of P. radiatus fertilizer to density and carotenoid content of D. salina. The research was conducted on March-May in the Natural Feed Laboratory, BBPBAP Jepara Central Java. The research method was used completely randomized design. The treatments used is P0 (control) (Walne 0,5 mL/L), and P. radiates fertilizer is treatments P1 (60 mL/L), P2 (120 mL/L), P3 (180 mL/L), with 3 replicates. The density of D. salina cells is observed for ten days. Carotenoid measurement in the exponential phase using a spectrophotometer.The results showed that the P. radiatus fertilizer as a media culture gives an effect on the density and carotenoid content of D. salina. Phaseolus radiatus fertilizer showed the best density and carotenoid content at dose 60 mL/L. The amount of density in the exponential phase was 476.67 x 104 cells/mL with a carotenoid content of 0.967 µg/mL.

Microalgae has an important role in the world of fisheries, because the availability of microalgae is needed as a natural feed in the hatchery business of fish and shrimp. One type of microalgae that is potential to be developed as a natural feed is Dunaliella salina. Factors that influence affect the density and carotenoids of D. salina is the intensity of light because it has an important role in the process of photosynthesis. This study aims to get the best light intensity in increasing the density and content of D. salina carotenoids. This research was conducted on 12-21 May 2019. Located in the Natural Feed Laboratory, Center for Brackish Aquaculture Fisheries (BBPBAP) Jepara. The research method used was a Completely Randomized Design with 4 treatments giving different light intensities namely P1 (2,500 lux), P2 (3,500 lux), P3 (4,500 lux) and P4 (5,500 lux) with 3 replications. Growth was observed for 10 days by calculating daily density and carotenoid content on the 6th day. The results showed that different light intensities affected the density and content of D. salina carotenoids. The highest density and carotenoid content was found in the light intensity of 5,500 lux with a density of 637.87 x 10 4 cells /ml and the carotenoid content of 1.45 µg /ml.

Dunaliella salina is a microalga containing carotenoids. Carorenoids have a role in the absorption of light for photosynthesis, carotenoids also function in coloring for aquaculture animals. Carotenoids is influenced by a variety of environmental factors, such as salinity. This study aims to get the best salinity in increasing the density and carotenoid content of D. salina. The research method used is an experimental method using a Completely Randomized Design (CRD) consisting of One factor with four improvements, to reduce the level of error then repeated three times. This research was conducted in March to May 2019 in the Laboratory Natural Feed Brackish Water Aquaculture Development Center (BBPBAP) located in Jepara Bulu Village, Jepara District, Jepara Regency, Central Java Province. Carotenoid analysis done in the Lab. Primary Chem-Mix located in Kretek, Jambidan, Banguntapan, Bantul, Yogyakarta. The treatment in this study included P1 (salinity 20 ppt), P2 (salinity 30 ppt), P3 (salinity 40 ppt) and P4 (salinity 50 ppt). The results showed that the cell ratio was highest filled in P2 with a concentration reaching 664.86 x 104 cells/mL and contents the highest carotenoid in P4 is 1.4769 µg/mL

This research was conducted in June 2019 to determined the abudance crown of thorn starfish (A. planci) and the condition of coral reef in Tikus island. 3 Stations with 2 different depth were taken in Tikus island. The result showed that coral reef from 4 meter depth were in middle-good condition. Percent cover of Station 1 was 44.4%, percent cover of Station 2 was 59.33% and percent cover of Station 3 with 59.04%. Meanwhile, 9 meters depth showed coral reef condition in a bad category 13.93-20.20% using Underwater Photograph Transect method. The abudance crown of thorn starfish (A. planci) in all stations were in normal condition with the highest abudance was 0.004 ind/m2 using Line Intercept Transect method. It means that A. planci hasn’t given a threat for coral reef ecosystem. The abudance of A. planci in each station and 2 different depth also didn’t show any different, based on depth and station.

This research was conducted in October 2018 at the West Rangsang Beach Waters, Meranti Islands Regency, Riau Province. This study aims to determine changes in shoreline that occurred in West Rangsang Sub-District in the last 10 years and the implementation of marine law regarding the regulation of shoreline change problems. Results of processing Landsat 5 and Landsat 8 images with large Changes in the coastline in the Melai Village were 55.56 m (accretion), in the Village of Kedabu Rapat as much as 50.94 m (abrasion) and in the village Bungur at 42.10 m (abrasion). The implementation of the law of the sea according to article 15 of UNCLOS 1982 in the determination of territorial sea areas adjacent to other countries decided the law No. 2 of 1971 concerning the determination of the borders of the two countries in the Malacca Strait. Determination of these coordinates are based on the baseline of each country. With the enactment of the 1982 International Law on the Law of the Sea, the Republic of Indonesia Government Regulation No. 38 of 2002 stipulated a list of geographical coordinates of the baseline points of the Indonesian archipelago. With the determination of geographical coordinates the problems in the changes in the coastline of the countries of Indonesia and Malaysia as a result of abrasion and accretion can be solved by observing the geographical coordinate points on the island of Rangsang

Mangrove leaves (R.apiculata) contain flavonoid compounds, terpenoids, steroids, saponins, and tannins which function as antibacterial and can improve fish health. This research was carried out in August to October 2019. This research purpose was to know the proper dose of mangrove leaf (R. apiculata) added to the feed to improve fish health as seen from total leukocytes, leukocyte differentiation, and phagocytic activity of P. hypophthalmus. The method in this research was the experimental method using the Completely Randomized Design (CRD) with one factor, four treatment levels and three times replication, so that it takes 12 units of experiments. The treatments were P0 (feed without additional extract R. apiculata), P1, P2, and P3 feed which were given extract R. apiculata at a dose of 1,5 mg/kg, 1,7 mg/kg and 1,9 mg/kg of feed. The fish used is P. hypophthalmus size 8-10 cm with a stocking density of 50 fish/m3. Feeding three times a day at 08.00, 12.00, and 17.00. Blood testing was performed three times, namely the beginning of the 1st, 30th, and 60th day of maintenance. The results showed that the addition of extract (R. apiculata) into the feed had a significant effect on total leukocytes, leukocyte differentiation, phagocytic activity, survival rate and growth of absolute weight of P. hypophthalmus. The best dose is 1,7 mg/kg of feed with total leukocytes 11,17x104 cells/mm3, lymphocytes 84,33%, neutrophils 6,67%, monocytes 9,00%, phagocytosis activity 35,00%, survival rate 97,33%, and absolute weight growth of 38,93g.

Rhizophora apiculata leaf extract has benefits as an herbal supplement that can be added to feed, because it have componds like flavonoid, tannins, saponins, terpenoids, and steroids that can improve the health of jambal fish (Pangasius hypophthalmus). This research was carried out in August to October 2019. The aim of the research was to obtain the best dose of R. apiculata leaf extract added to feed to improve the health of jambal fish as seen from total erythrocytes, hemoglobin levels, hematocrit levels, and erythrocyte morphology. The method was used an experimental method with a Completely Randomized Design (CRD) one factor of four treatment levels consisting of P0: without the addition of extracts; P1: (1.5 mg/kg); P2: (1.7 mg/kg); and P3: (1.9 mg/kg) and repeated three times so that it takes 12 units of the experiment. Maintenance is carried out for 60 days in cages net with a size of 1x1.5x1 m3. The Blood tests were carried out three times, at the beginning of maintenance, 30th day, and 60th day. The best dose was in the P2 treatment (1.7 mg/kg) seen in total erythrocytes 2.57x106 cells/mm3, hemoglobin level 13.13 g/dL, hematocrit value 38.43%, absolute weight growth 38.93 g, survival rate 97,33%, and showed normal erythrocyte morphology, it was supported by water quality during the reasearch such as DO 6.4-6,9 mg/L, pH 6.1-6.8, temperature 28.2-29.50C, and ammonia 0.04-0.08 mg/L.