ANALYSIS OF COASTLINE CHANGES ON THE POTENTIAL OF MANGROVE FORESTS ON BENGKALIS ISLAND, RIAU PROVINCE

This study was conducted from January to February 2021 in coastal areas of Bengkalis Regency that is in Riau Province. This study aims to know the coastline changes to the potency of mangrove forests in that area. Field data was collected by survey methods such as direct observation and questioners, and it used different times of satellite imageries to find out the coastline changes over time. The results showed that the coastline of this regency had changed as much as 1036 Ha in average from the year of 1988 to 2020. It was due to coastal abrasion, wave actions, and reduction of mangrove forests; the coastline change reached 12.02 meters per year as the highest. The mangrove forest in the region of this regency plays important roles to the local life, the local economy, and the coastal waters; it was for fishermen, charcoal production, coastal tourism, and transportation as well.

ABILITY OF AMILOLYTIC BACTERIA (Bacillus paramycoides and Enterobacter cloacae) IN DEGRADING ORGANIC MATERIALS OF MANGROVE LITTLE

This study aims to find out that Bacillus paramycoides and Enterobacter cloacae bacteria can produce amylase enzymes and have the ability to degrade organic matter, especially mangrove litter. From this study it was found that the optimal growth of B.paramycoides and E. cloacae bacteria occurred at 12th hour. The results of measurements and calculations of absorbance values ​​at 630 10.238 x 108 cells/mL (B. paramycoides) and 12.030 x 108 cells/mL (E. cloacae) using the spectrophotometric method. Meanwhile, with the TPC method at 12 hours, the number of bacterial cells was 2.08 x 108 CFU's/ml (B. paramycoides) and 2.44 x 108 CFU's/ml (E. cloacae). The ability to produce the largest amylolytic bacterial amylase enzyme also occurred at 12 hours as much as 0.306 mg/mL (B.paramycoides) with an increase of 0.046 mg/mL and 0.243 mg/mL (E. cloacae) with an increase of 0.028 mg/mL. The bacteria that have the highest amylase enzyme ability is E.cloacae as evidenced by the diameter of the clear zone of 10.10 mm. Testing the ability of amylolytic bacteria in degrading mangrove litter was carried out by adding amylase enzyme as much as 0%, 50% and 100%. Amylolytic bacteria can degrade organic matter by hydrolyzing starch contained in mangrove litter. The most degraded starch content was in the 100% enzyme treatment, which was 1.021 mg/mL (B. paramycoides) and 1.189 mg/mL (E.cloacae).

STUDY OF GILL, KIDNEY AND LIVER STRUCTURE OF Pangasius hypophthalmus IN THE TANJUNG KUDU LAKE AND SAIL RIVERS, RIAU PROVINCE

Environmental condition and water quality in general may affects the health status of fish and it represents in the structure of fish organs such as the gill, kidney, and liver. To understand the structure of the gill, kidney, and liver of Pangasius pangasius that live in the Tanjung Kudu Lake (good water quality) and in the Sail River that has been polluted, a study has been conducted from November to December 2020. Twelve fishes (6 fishes/river) were analyzed. The tissue was formalin-fixed and processed through alcohol series, paraffin-embedded, 5m sliced and Hematoxylin-Eosin stained. The histological samples were then studied using a binocular microscope Olympus CX 21. The abnormality level of the tissue was categorized using the Histopathological Alteration Indeks (HAI). Results showed that the fish tissues from both study sites indicate light abnormality signs such as hyperplasia, hypertrophy, and lifted epithelia. The HAI was 2 for fish from the Tanjung Kudu Lake and 3 for the fish from the Sail River. This index indicates that the abnormality may be cured as the water quality improved.

GROWTH CIRCLE PATTERNS IN THE OTOLITH OF THE GRAY FISH (Osteochilus melanopleurus) FROM THE SIAK AND KAMPAR RIVERS

Osteochilus melanopleurus can be found in the Siak and Kampar Rivers. The Kampar Rivers waters are better than that of the Siak River and it affects the growth of the fish. The growth pattern is reflected in the pattern of otolith growth rings. The research aims to understand the pattern of otolith growth rings of the O. melanopleurus from both rivers has been conducted from January to February 2021. There were 55 fishes captured (28 males and 27 females). The otolith was taken using tweezers and shaved manually using a soft grindstone. The dark growth ring pattern was investigated using a binocular microscope. Results showed the size of fish captured was 220 to 360 mm from Siak River and 310 to 370 mm from Kampar River. In the fish with the same standard length, the size of the otolith from the Siak River is heavier and longer than that of the Kampar River, which means that fish growth from the Kampar River is better than that of the Siak River. The length of an otolith from Siak River ranged from 1.875 – 3.275 mm, the width was ranged from 1.575–2.75 mm and the weight of otolith was 0.0039 – 0.0098 g, while the length of an otolith from Kampar River ranged from 2.375–3.275 mm, the width was ranged from 1.85–2.575 mm and the weight of otolith was 0.0042 –0.0076 g. The maximum number of the dark ring in the otolith from the Siak River was 4 and Kampar River was 2. The distance between the nucleus and the first dark ring of fish from both rivers was varied from 0.1–0.525 mm, and there was no special pattern. This fact indicates that the first dark ring was formed individually and they were not formed by a periodical incidents during the fish life

MACROZOOBENTHOS COMMUNITY STRUCTURE IN INTERTIDAL ZONE OF SAMBUNGO VILLAGE PESISIR SELATAN REGENCY OF WEST SUMATERA PROVINCE

This research was conducted in the village of Sambungo, Silaut District, Pesisir Selatan Regency, West Sumatra Province in August 2020. The purpose of this study was to determine the structure of the macrozoobenthos community which includes: type, density, diversity, uniformity, dominance and distribution patterns. Sampling was done randomly at 3 stations, each station consists of 3 transects and each transect consists of 3 plots, namely in the upper middle and lower in the intertidal zone. The results of the study found 5 classes of macrozoobenthos with 9 species. The abundance values ​​obtained ranged from 3.33 - 5.11 ind/m2. The diversity index value ranges from 1.18-1.54 which is classified as moderate, while the dominance index value ranges from 0.39-0.52, namely there was no species that dominate, the uniformity index value ranges from 0.03-0.06 which is not balanced and the value of the distribution pattern ranges from 2.81 to 3.76 with the pattern of distribution in groups

ANALYSIS OF LAND COVER CHANGES IN MANGROVE VEGETATION USING LANDSAT IMAGE DATA IN COASTAL, SUNGAI APIT DISTRICT, SIAK REGENCY, RIAU PROVINCE

This research was conducted in March-April 2021 in the Coastal District of Sungai Apit, Siak Regency, Riau Province. The purpose of this study was to analyze changes in the land cover area of ​​mangrove vegetation and mangrove vegetation index in Sungai Apit District, Siak Regency, Riau Province. The method used in this study is a survey method with the interpretation of Landsat image data recorded in 2000, 2005, 2010, 2015, 2020. The results of the study obtained that mangrove forests with the highest area were in 2000 with an area of ​​mangrove vegetation reaching 7990,586 ha and there was a decline with the lowest number in 2015 with a vegetation area of ​​486,43 ha and in 2020 the mangrove vegetation area of ​​497,511 ha. Overall as much as 79% of the mangrove forest area has been damaged and changed its function within a period of 20 years. The NDVI value in Sungai Apit District is moderate with a value of 0,3-0,5, the category of meeting with a value of 0,5-0,6, and the very dense category of 0,6-0,8

TOXICITY OF SEA GRASS EXTRACT (Eucheuma cottonii AND Gracillaria sp) TO LARVA Artemia salina

Seaweed is a source of foreign exchange, namely as a main export product and a source of income for coastal communities. Previous research on species Eucheuma cottonii and Gracillaria sp contain bioactive compounds that can be used in medicine, for example as anti-cancer. The purpose of this study was to determine the LC50 value and safe concentration of Artemia salina larvae. The research was conducted at the Chemical Oceanography Laboratory of the Department of Marine Sciences, Faculty of Fisheries and Marine, Riau University in July 2020. The method used in this research is the experimental method. The results of the research on the toxicity of the n-hexane extract of seaweed E. cottonii and Gracillaria sp had bioactivity compounds against A. salina shrimp larvae, indicated by a small LC50 value (<1000 ppm), namely 62.62 ppm for E. cottonii and 83.55. ppm for Gracillaria sp, so it is included in the toxic category. According to research by experts, if the extract or compound tested is less than 1000 ppm, it is considered that there is biological activity. For a safe concentration for the survival of A. salina, 6.262 ppm for E. cottonii and 8.355 ppm for Gracillaria sp.

POPULATION CONDITIONS OF ECHINOIDEA AND CORAL REEF COVERS IN PONCAN GODANG ISLAND, SIBOLGA, NORTH SUMATERA

Poncan Godang Island is included in the appropriate category based on the suitability of land for the Sibolga tourist area, with the presence of tourism activities that can also affect the amount of biodiversity in it. Considering the importance of coral reefs for biodiversity and sea urchins which also have a role in coral reef ecosystems, it is necessary to conduct research on the condition of sea urchins population and the percentage of coral reefs on Poncan Godang Island. Sea urchin and coral reef data were collected using the Line Intercept Transect (LIT) method by monitoring directly on the transect line along 50 meters. The results obtained indicate that the population of sea urchins in the waters of Poncan Godang Island, North Sumatra can be described, that sea urchins do not affect the coral reef ecosystem because at stations 1 and 5 there is no sea urchin and the percentage of coral cover is classified as bad, but at station 3 there are 32 individuals with coral reef cover conditions, while at stations with The percentage of good coral cover is that at station 4 there are only 25 individuals, as well as at station 2 where the percentage of coral cover is higher than station 3 and there are no sea urchins

CORAL REEF COVER RELATIONSHIP TO POMACENTRIDAE AND PHYTOPLANKTON CORAL FISH IN KASIAK ISLAND OF WEST SUMATRA PROVINCE

Kasiak Island is one of the islands located in the waters of Pariaman, West Sumatra, and located right in front of Pariaman City. Around the sea, the island is surrounded by coral reefs and is a protected area. In the aquatic area of Kasiak Island has never been conducted research on the relationship of coral reef cover to the coral Pomacentridae and phytoplankton. Therefore, it is necessary to conduct research on this matter in the waters of Kasiak Island, West Sumatra Province. Data collection of coral reef cover is done by the LIT (Line Intercept transect) method with a transect length of 50 meters at a depth of 5 meters using scuba equipment. Coral fish observation is done by UVC (Underwater Visual Census) method with a transect length of 50 meters and an observation area of 2.5 meters left and right at a depth of 5 meters. Phytoplankton sampling is conducted during the day at 11.00 to 15.00 WIB at five points of the station with a depth of 5 meters using Vandorn water sampler volume 2 L with a total take of 100 L, then filtered using Plankton net no 25 and inserted into a sample bottle of 125 ml, then preserved using Lugol 4% as much as 4-6 drops, after which analyzed in the laboratory. Based on the results there is a very strong relationship between coral cover to the abundance of coral fish, where coral cover contributes to the abundance of coral fish by 93.87%, which means that the higher the percentage of coral cover the more species and abundance of coral fish are found. Then the a strong relationship between coral reef cover and phytoplankton abundance, where coral reef cover contributes to the abundance of phytoplankton by 56.37%, which means an increase in the percentage of coral reef cover along with the increasing abundance of phytoplankton.

ANALYSIS OF ORGANIC MATERIAL CONTENT AND ABUNDANCE OF MACROZOOBENTHOS IN THE SOUTH BENGKALIS ISLAND, RIAU PROVINCE

This study was conducted in July-August 2020 by using sediment samples and macrozoobenthos in the southern part of Bengkalis Island, Riau Province. The aim of this study is to find out how much the organic matter content, the abundance of macrozoobenthos, and the correlation between the organic matter content of the sediments to the abundance of macrozoobenthos. This study used a survey method consisting of 3 stations with 3 transects in each station. The organic matter content of sediments revolved from 4.85 to 8.52% in the waters of the southern part of Bengkalis Island. The highest organic matter content was at station III, namely 8.52%, while the lowest organic matter content was at station II namely 4.85%. The abundance of organisms found at the three research stations was 4.04 to 5.96 ind/m2. The abundance average at all macrozoobenthic research stations was 4.93 ind/m2. The results of simple linear regression analysis of organic matter content and abundance of macrozoobenthos showed a very weak correlation