Jurnal Ilmu dan Teknologi Kelautan Tropis

Front Matter

Dietriech G Bengen — 2023-12-31

Front Matter

ANALYSIS OF COASTLINE CHANGES AND ECOLOGICAL RESILIENCE IN TANGERANG COASTAL AREA, BANTEN PROVINCE

Ella Yuni Astuti — 2023-12-31

The coastal area of Tangerang Regency experiences continuous changes caused by natural factors and human activities. These ongoing changes can affect the level of resilience on the coast. This study aimed to assess the level of resilience based on the dynamics of coastline change and ecological conditions, as well as its relation to land use and land cover on the coast of Tangerang Regency. Data analysis consisted of processing Landsat satellite imagery, land use and land cover (LULC) analysis, and coastline change rate using Digital Shoreline Analysis System (DSAS), oceanographic data processing, and resilience assessment. The results showed that the coast of Tangerang Regency has a low level of resilience, with the dynamics of coastline change being more dominant in erosion than accretion. The rate of coastline change was positively correlated with LULC. Erosion occurred in areas where ponds were dominant, and few mangroves were present, while accretion occurred in estuaries and industrial areas.

POPULATION DYNAMICS OF THE THREE-SPOT SWIMMING CRAB (PORTUNUS SANGUINOLENTUS) IN PATI WATERS, CENTRAL JAVA

Kamal Mustabiq — 2023-12-31

Currently, Portunus sanguinolentus is one of the fishery commodities that has experienced a decline in population due to exploitation pressures and habitat or environmental damage. This has an impact on changes in the population structure and reproductive strategy of P. sanguinolentus, with parameters that can change, among others, the size of the first gonad becoming smaller, changes in spawning areas and seasons, and changes in the balance of the sex ratio. This study aims to determine the population dynamics of P. sanguinolentus in Pati Regency, Central Java, and whether it is useful for the processing industry to make a new product. Data and information were obtained through observation, interviews, and enumeration, which were carried out at each fish landing site. Collecting data from catches in fishing areas below 12 miles with a maximum depth of 15 m for 5 months. The FISAT II software was used to analyze the growth parameters, mortality rate, and exploitation rate. Obtained weight data of 7.72 kg with a total sample of 107 ind. Detailed data were obtained for 46 females with an average width of 106.24 mm and 61 males with a width of 103.95 mm, and the average weight of the entire sample was 74.26 g.

SEA SURFACE TEMPERATURE DISTRIBUTION IN LAMPUNG BAY BASED ON LANDSAT-8 IMAGES AND ITS RELATION TO THE INDIAN OCEAN DIPOLE (IOD) ON THE PERIOD YEAR 2013-2021

Dema Okgareta — 2023-12-31

Sea surface temperature is an important oceanographic attribute in ocean waters, that changes of sea water temperature can change aquatic ecosystems. Lampung Bay waters originating from the Indian Ocean and the Java Sea which pass through the Sunda Strait will be influenced by the Indian Ocean Dipole (IOD). This study aims to analyze spatial and temporal inter-annual Sea Surface Temperature (SST) distribution patterns in the last 9 years (2013-2021) and analyze the Indian Ocean Dipole (IOD) phenomenon that caused an anomaly of SST in Lampung Bay. The method used in this study is a regression validation method, descriptive method and correlative statistics. The results showed that the SST value of Landsat-8 image extraction can represent in situ SST conditions because R²=0.6872. The IOD phenomenon influences the Lampung Bay water’s SST distribution pattern. Positive IOD phase years (2015, 2018 and 2019) or negative IOD phases (2013 and 2016) shown SST of Lampung Bay waters has a different distribution pattern and anomalous values. But correlation between IOD and SST in Lampung Bay had two different result which in open water (TL3, TL4, and TL5) is mid-correlate (r>0.7) and weak correlation (r<0.2) at observation points TL1 and TL6 which are close to the mainland.

POPULATION PARAMETERS OF BLUE SWIMMING CRAB PORTUNUS PELAGICUS IN THE TIWORO STRAIT, SOUTHEAST SULAWESI

Muhamad Cardin APRI — 2023-12-31

The blue swimming crab (Portunus pelagicus) has a wide distribution in the fishing ground waters for fishermen's activity in the Tiworo Strait. The coastal area of Tiworo Strait has quite a lot of crab potential. Therefore, it is used as one of the pilot locations for sustainable crab management projects of the Indonesian Blue Swimming Crab Association (APRI). Growth, total mortality, natural death, fishing mortality, and the exploitation rate were the population parameters of crabs that need to be known so that management can be carried out in a sustainable manner of fisheries. A study on the population parameters of crabs has been conducted in the Tiworo Strait, based on carapace width frequencies data collected from Juli to December 2021 and analyzed using FISAT (FAO-Iclarm Stock Assessment Tool) II. The total sample is 7,809 samples, where the number of male blue swimming crabs is 3,295 samples and 4,514 females. The average size of the blue swimming crab carapace width caught was 107.57 mm for males and 110.65 mm for females. The results of the study showed that the growth rate (K) was 1.01/year, the total mortality rate (Z) was 0.67/year, the natural death rate (M) was 1.25/year, and the fishing mortality rate was 0.58/year. The exploitation rate (E) of blue swimming crab was 0.86, which showed symptoms of over–exploitation, so the management of crabs in these waters must be carried out more carefully to sustain the availability of crab resource stocks.

Keywords: blue swimming crab, width, weight, Tiworo Strait

ANALYSIS OF LONGSHORE CURRENT AND LONGSHORE SEDIMENT TRANSPORT AT AENG BEACH, NORTH GALESONG, TAKALAR REGENCY

Hasdinar Umar — 2023-12-31

Located in the coastal region of Takalar Regency, Aeng Beach has possibilities for tourism, industrial, fishing, and seaweed industries. It shares a straight border with Makassar City. But practically all coastal regions have the issue of abrasion along the Takalar Regency's shore as a result of coastal currents. Investigating the direction and speed of longshore currents and their impact on the movement of silt down the shore is the goal of this study. Based on ten years of wind data from BMKG Region IV Makassar City, wave data analysis employs a wave forecasting technique. Empirical equations are used to calculate longshore current speed and longshore sediment transport. Based on the analysis, it can be observed that the breaking wave depth (d_b) varies between 2.1 and 2.5 meters, while the breaking wave height (H_b) ranges from 1.64 to 2.00 meters. The longshore current direction of the coast is east to west, and the speed ranges from 4.13 to 4.55 m/sec. According to the direction of the dominant incoming waves, the longshore sediment transport ranges from 13,159.93 – 19,674.25 m3/day or 4,803,373 – 7,181,101 m3/year from west to east. This indicates that fine sand to coarse sand dominates the sediment in the Aeng Beach area. Aeng Village Beach's abrasion management can be determined using the research findings as reference data. One of the structural treatments that can be implemented is the construction of permeable groin structures, which can regulate the quantity of sediment carried down the shore and preserve the stability of the coastline.

BLUE SWIMMING CRAB ENLARGEMENT TECHNIQUE: INSIGHT FROM SMALL-SCALE FISHERY IN THE SOUTH COAST OF PAMEKASAN, MADURA ISLAND

Lailatul Qomariyah — 2023-12-31

Pagagan Village, Pademawu District, and especially members of the "Berkah Capit Biru" fishermen, had the potential to carry out the sustainability of blue swimming crab because of the abundant crab fisheries. The purpose of this research was to encourage fishermen to not always carry out crab fishing activities in nature so nature remained sustainable and to increase the potential of natural and human resources who were enthusiastic about crab enlargement in Pagagan village. This research was conducted from January to May 2022. The crab breeding location measured 8x10 meters, had a substrate of muddy sand, and was in a coastal area bordering a mangrove ecosystem. Wooden stakes woven with bamboo with a netting around them were set higher than the wave. This enlargement technique did not use aeration in the form of wheels but only utilized tidal conditions so that periodic water changes occurred at the site. The stages in the crab enlargement technique are 1) site selection, 2) construction, 3) spreading seeds, 4) feeding, 5) controlling, and 6) harvesting. This enlargement technique is a solution for crab fishermen to meet market stocks.

Keywords: blue swimming crab, enlargement technique, small-scale fishery

DNA BARCODING, MORPHOLOGICAL IDENTIFICATION AND POPULATION DENSITY OF GENUS TRIDACNA IN NORTH MALUKU WATER

Namira Hadadi — 2023-12-31

Tridacna (kima) is a giant bivalve that is important to ecology. Attractive sizes and colours are the main attraction of overexploitation. Protection must occur, such as density measurement, size variations, and species identification based on morphology and DNA barcodes. This study aimed to identify clams using the DNA barcode method and to evaluate their population size and density in North Maluku waters. The research method uses DNA barcodes, morphological identification of mantle colour and shell size variations, and measurements of the density of clams found in North Maluku waters. The results were helpful based on DNA barcoding. They helped detect the morphology of the same results. Namely, three types of clams, Tridacna crocea, Tridacna squamosa, and Tridacna maxima, were detected. Differences in the shell's size and shape and the mantle's colour strengthen the three types as distinct species. In addition, the clade shape of the phylogenetic tree between the samples and GenBank data from the same clade. The condition of clam density in these waters showed the same results as other locations, namely less than 1/m2. A value density of < 1 m2 may suggest that the species is declining or lead to over-exploitation. Thus, this research data can be used as a reference for assessing chemical conservation activities.

EARLY WARNING SYSTEM (EWS) FOR ALGAL BLOOMS USING SATELLITE IMAGERY IN JAKARTA BAY

Tumpak Sidabutar — 2023-12-31

Jakarta Bay is experiencing eutrophication, primarily due to nutrient inflows from agriculture, industry, and urban sources. This abundance of nutrients has led to significant algae blooms. A study using Terra and Aqua MODIS satellite data from 2004 to 2007 monitored these blooms by measuring chlorophyll-a levels. During this period, large-scale fish kills were observed directly related to the algal blooms, as evidenced by high chlorophyll-a concentrations and blooms covering more than a quarter of the bay. Interestingly, not all intense blooms resulted in massive fish kills. The study suggests that this mortality is primarily due to oxygen depletion after peak bloom periods, compounded by poor water circulation in the bay. Using satellite imagery to monitor algal blooms is a practical tool for implementing an early warning system (EWS) in Jakarta Bay. Satellite imagery has proven effective in monitoring these blooms and could help develop an early warning system in Jakarta Bay despite limitations such as cloud cover.

Back Matter

Dietriech G Bengen — 2023-12-31

Back Matter