East Season Research Articles

Analisis Hadis dalam Khanduri Laot pada Masyarakat pesisir Aceh Tamiang

The Khaduri Laot tradition is a traditional ceremony that must be carried out by the coastal communities of Aceh Tamiang, especially at the end of the west season or before the east season. This tradition has been carried out routinely by every village under the Panglima Laot area. For the local fishing community, Khaduri Laot reflects the relationship between humans, their creator, and the surrounding environment. This ceremony is believed to have a major influence on the safety of fishermen and the blessings of marine products. Khaduri Laot is considered a cultural tradition that must be maintained and preserved. Local people's beliefs state that not carrying out this ceremony can bring disaster or danger. On the contrary, the Khaduri Laot celebration is believed to bring blessings and abundant sustenance to fishermen and coastal communities. In addition, this ritual is also believed to provide protection and security for fishermen who sail at sea. This tradition not only has a spiritual dimension, but also a cultural one in maintaining harmony between humans and nature.

Catch composition and fishing season of blue swimming crab using a collapsible trap in Pemalang coastal water, Central Java

Abstract The blue swimming crab (Portunus pelagicus) is an economically important fishery resources that has penetrated the export market that requires proper management. Pemalang Regency is still entirely dependent on natural catches, so information on seasonal patterns of blue swimming crab fishing is essential for fishermen to support the efficiency and effectiveness of the fishing activity. This research was conducted in Danasari village, Pemalang sub-district, in January–December 2022 with the aim of determining the composition of collapsible trap catches based on the crab fishing season in the waters of Pemalang Regency. Danasari fishermen classify the blue swimming crab fishing season into two, the west season starts in November–May (high rainfall), and the east season starts in June–October (low rainfall). The survey method was performed by collecting data of blue swimming crab catch as the main target and bycatch. Carapace width of the blue swimming crab was also measured. The data obtained was analyzed descriptively using Microsoft Excel 2010 software. The results showed that the catch composition of collapsible traps in Pemalang consisted of crustaceans, fish, and mollusks. The best season to catch blue swimming crabs was during the west season because the catch is more stable than during the east season.

Seasonal effects on blue swimming crab catch per unit effort (CPUE) in Tiworo Strait, Southeast Sulawesi, Indonesia

Abstract Blue swimming crab (BSC) resources are fisheries commodities that have important economic value, so their utilization needs to be carried out sustainably. Understanding crab fishing season patterns is very important in efforts to improve the efficiency and effectiveness of crab fishing industry. This study aimed to analyze the abundance and catch per unit effort (CPUE) of blue swimming crab based on season in the the Tiworo Strait, Southeast Sulawesi, Indonesia. BSC sampling was conducted monthly from October 2022 to March 2023 (west season) and April to September 2023 (east season). The results showed that the maximum catch occurred during the east to west transition season, amounting to 1,668.50 kg, while the lowest catch was 376.70 kg with a total of 1,032 trips. The maximum catch in the west season was 1,402.10 kg, while the lowest was 666.50 kg with a total of 1,265 trips. The highest CPUE value was observed in July at 7.92 kg/trip, while the lowest CPUE occurred in April at 2.18 kg/trip. Differences in crab catches and number of trips in each season may be influenced by environmental conditions that occur in that season as well the location of the fishing ground.

Export demand patterns for blue swimming crab from Indonesia to United States : impact of fishing seasons in FMA 712 (2018 to 2022)

Abstract Blue swimming crab (Portunus pelagicus) is a significant fishery export commodity from Indonesia, especially the fisheries management area (FMA) 712. The aim of this study was to analyze the relationship between export demand and fishing season in FMA 712 during the last five years (2018–2022) based on export volume, prices, and fishing season information. Fishing season in Indonesia was classified as the west season with high rainfall (November to May) and the east season with low rainfall (June to October). The data were analyzed by correlation and trend analysis. The results showed that the export demand for blue swimming crab fluctuated with the fishing season. Demand for blue swimming crab tends to increase in the west season due to abundant supply from a favorable fishing season, leading to decreased prices due to international market competition. Conversely, demand for blue swimming crabs declines in the east season due to reduced supply from an unfavorable fishing season, resulting in increased prices due to limited availability. To address fluctuations, market diversification, product quality improvement, and sustainable fishery resource management are essential to balance profitable exports and marine preservation. Other variables that may influence export demand, such as global economic and political factors, were not included in this analysis.

The Seasonal Variations of the Thermocline in the Banda Sea and its Water Mass Characteristics

This research was conducted to examine the seasonal variations in the Banda Sea's thermocline layer and its water mass characteristics. The research was conducted by analyzing Argo Float data. The data consists of six observation stations in West Season and Transitional Season II, and four stations in Transition Season I and East Season The thermocline layer thickness was identified based on the depth where the temperature decreased ≥ 0.05oC/m. The thermocline layer's distribution of depth and thickness and the distribution of temperature and salinity seasonally in the thermocline layer were analyzed with Microsoft Excel 2010. The analysis results showed that East Season and Transition Season II have a shallower upper boundary depth of the thermocline layer, a deeper lower boundary of the thermocline layer, and the thermocline layer is thicker when compared to the West Season and Transition Season I. The average temperature distribution is higher and the average salinity is lower in the West Season and Transition Season I. The mean rate of change in salinity and temperature in the thermocline layer seasonally ranged from 0.002-0.004 PSU/m and 0.06-0.08oC/m. The thermocline layer's stratification is stronger in the West Season and Transition Season I.

Seagrass blue carbon stocks and air-sea CO2 fluxes in seagrass meadows Jepara, Indonesia

Abstract This research was conducted on August 2022 (east season) and February 2023 (west season) in Jepara waters. There are four types of seagrasses found: Ea (Enhalus acoroides), Cr (Cymodocea rotundata), Os (Oceana serrulata), and Th (Thalassia hemprichii). The analysis results suggest that the Os species has the largest organic carbon stock within seagrass (OCS-Sg), whereas Ea has the lowest. Aside from morphological measures, in this study seagrass shoot density also determined OCS-Sg for each type of seagrass. This study found that OCS-Sg is higher during the east season (26.2±2.81 gCorg m−2) than the west season (11.2±1.78 gCorg m−2). Whereas, organic carbon stock within sediment (OCS-S) is lower during the east season (41.5±0.9 gCorg m−2) and higher during the west season (56.3±0.9 gCorg m−2). During the east and west seasons, Jepara waters act as a CO2 source. However, during the east and west seasons vegetated OCS-S had higher carbon storage (41.9 and 57.2 gCorg m−2) than unvegetated (39.2 and 53.7 gCorg m−2). This is also indicated by the CO2 flux in vegetated which is lower (13.1±4.8 mmol CO2 m−2 d−1) than unvegetated (16.5±4.7 mmol CO2 m−2 d−1) during the east season. On the other hand, vegetated waters have higher CO2 flux (22.7±2.7 mmol CO2 m−2 d−1) in the west season than unvegetated (18.0±2.5 mmol CO2 m−2 d−1), this is related to seagrass shoot density during the west season which is decreasing. These findings lead to the conclusion that seagrass plays an important role for storing and absorbing carbon and storing carbon and store it in seagrass biomass and sediment even though the role of waters returns CO2 back to the atmosphere.

Primary Productivity Variation in Banten Bay and Java Sea and Its Relationship with Fish Catches

Abstract Ecosystems carry out internal activities, one of which is by carrying out production which is the process of inputting and storing energy from sunlight as a primary energy source called primary productivity. The development of wider coastal areas is a major factor in the importance of assessing the quality of water fertility as a measure of ecosystem change. The aim of this research is to predict the value of primary productivity in Banten Bay and the Java Sea seasonally from 2005-2020 based on MODIS Fluorescence satellite image data and processed using the Vertically Generalized Production Model (VGPM). Net Primary Productivity results obtained in Banten Bay in the West Season 148.23 mgC.m−3.d−1; Transitional Season I 148.06 mgC.m−3.d−1. East Season with 154.05 mgC.m−3.d−1; Transitional Season II 170.10 mgC.m−3.d−1 while in the Java Sea in the West Season 100.05 mgC.m−3.d−1; Transitional Season I 82.20 mgC.m−3.d−1; East Season 110.84 mgC.m−3.d−1; Transitional Season II 95.97 mgC.m−3.d−1 which decreased in value from 2005 to 2020 in both regions. Water fertility in Banten Bay and the Java Sea is higher in the nearshore area than the open sea which is influenced by chlorophyll-a, PAR availability, day length, temperature, maximum carbon fixation, euphotic zone depth, and area. Trophic status in each season in Banten Bay is included in the Oligotrophic class while in the Java Sea it is included in the Oligotrophic and Mesotrophic classes. NPP has a positive correlation with the overall capture of small pelagic fish species of 0.654 (average).

TWO-DIMENSIONAL FLOW PATTERN MODEL IN THE WATERS OF BAKAU BAY BINTAN DISTRICT

Ocean currents are the movement of sea water masses in a certain direction caused by several factors, namely wind, tides and bathymetry. Hydrodynamic modeling aims to determine the speed and direction of ocean currents in the waters of Bakau Bay through a two-dimensional model. The current pattern of the north season to the east season is influenced by sea water masses with an average current speed ranging from 0.22-0.24 m/s, while the south season to West season currents with an average speed of 0.04-0.26 m/s, this shows the meeting of different water masses so that the speed and direction of the current results in random or rotating currents. From the calculations of the normality test and anova test, it is known that the field current and model simulation values are normally distributed and there is no significant difference in values in the two data, so based on the RMSE value, it shows that the difference in values between the model simulation results and direct data measurements is relatively small. This also shows that the ocean surface current model created is sufficient to describe actual conditions.

THE RELATIONSHIP OF THE DISTRIBUTION OF SEA SURFACE TEMPERATURE WITH RAINFALL AND WIND IN THE WATERS OF WEST SUMATRA

This research was carried out in February-March 2023 in the West Sumatra waters. It aimed to determine the variability of sea surface temperature, rainfall intensity, wind direction, and speed in the West Sumatra waters. Sea surface temperatures were taken from three stations, namely: in the coastal waters of Pariaman City, Padang-Pariaman Regency, and Bungus, Padang. The survey method was used, which was directly observed in the field. The results showed that the Sea Surface Temperature of the study areas ranged from 29.25oC-30.28oC, while the rainfall went from 211.97-499.89 mm, and the dominant speed was between 0.50-2.10 m/s. The correlation analysis between rainfall and sea surface temperatures in Station 1 yielded an "r" value of 0.871, a powerful correlation category, and the determination coefficient (R2) was 0.579 or 57.9% during the western season. In the east season, the "r" value was 0.321, in the moderate correlation category, and the determination coefficient was 0.103 or 10.3%. At Station 2, the correlation coefficient (r) was 0.788, a powerful correlation category, and the determination coefficient (R2) was 0.622 or 62.2% during the western season. In the east season, the "r" value was 0.699, a strong correlation category, and the determination coefficient was 0.488 or 48.8%. At Station 3, the "r" value was 0.688, a strong correlation category, and the determination coefficient was 0.477 or 47.7% during the western season. In the east season, the "r" value was 0.743, a strong correlation category, and the determination coefficient was 0.579 or 57.9%

Variabilitas musiman terhadap hasil tangkapan Tuna Madidihang (Thunnus albacares)

Fishermen in North Buru often depend on seasonal changes in tuna madidihang abundance to plan their fishing operations. However, a more comprehensive understanding of how this seasonal variability affects catches and its implications for fisheries management is still an important research subject. The research was conducted in Wailihang Village, Waplau District, North Buru Regency, between October and December 2022. The observational method was used for this study, where available and precise time series data owned by the Indonesian Community and Fisheries Foundation (MDPI) was collected. The collected data is the number of catch productions (kg) and the total length of fish (cm) from each haul. Yellowfin tuna production tends to fluctuate, with the highest catch (CPUE) occurring in September (63.8%) and the lowest in June (34.2%). The west season and east seasons have a total catch of 556 fish (45.42%), with 382 fish (31.21%) caught during the east season and 174 fish (14.22%) caught during the west season. The distribution of fish length varies in the east season compared to the west season. The west season catches more fish, but they are generally small-sized, while during the east season, large fish dominate, with the highest presentation (38.67%).

The effect of intake channel length on water temperature at the intake point of the power plant at Muara Karang power plant

Muara Karang Power Plant (MKPP) is one of the main power plants on Java Island in Indonesia. Presently, the Jakarta provincial government has issued a reclamation project on Island G in the marine waters around MKPP. This reclamation effort is predicted to lead to a rise in the seawater temperature around the intake, which MKPP will address with the addition of intake channel of 250 - 957 m. Therefore, this study aimed to determine the effect of intake channel extension on the water temperature at the intake point using numerical modeling comprising hydrodynamics and dispersion advection modules. A total of 10 scenarios were modeled by varying intake channel length and season. The result showed that adding intake channel was less effective because the average water temperature was less than 0.24oC with an effectiveness below 0.78%. Based on the validation of the modeling results on the measurement data, the NRMSD values in west and east seasons were 9.13% and 12.63%, respectively. Under existing conditions, the average and maximum seawater temperatures were 31.40oC and 32.08oC. Meanwhile, by extending intake channel, the average and maximum water temperatures were 31.16oC and 31.60oC. These results showed that by extending intake channel, the temperature at the intake point was generally lower than the existing conditions. Intake channel length was more effective in reducing the temperature at the intake point during west monsoon than east monsoon. Vertically, the temperature at the bottom was relatively colder than near the surface. In west monsoon, the average temperature difference between the bottom and the surface ranged from 0.16-0.21oC, while in east, it was between 0.23 and 0.50oC. In conclusion, the addition of subsequent structures to increase effectiveness was necessary, specifically to hold hot water in east monsoon.

Understanding sea wave height conditions in sumatra waters

Ocean waves play a crucial role in influencing a wide range of marine and fisheries activities. In this research study, we aim to analyze the climatological conditions of sea wave heights in Sumatran waters over a span of 83 years (1940-2022). We utilize three-dimensional Copernicus numerical model simulations to examine seasonal patterns of sea wave heights and assess the likelihood of extreme wave events. Our findings reveal that high waves, reaching heights of 4-5 meters, are predominantly observed in the western and southern zones off the coast of Sumatra, particularly in the vicinity of smaller islands. Conversely, in enclosed or semi-enclosed waters, such as the lee side of Sumatra and the Malacca Strait, sea wave heights tend to be relatively lower. Seasonally, our study indicates that extreme wave heights are more likely to occur during the west season as opposed to the east season. This research provides valuable insights into the dynamic ocean wave conditions in Sumatran waters, which can have significant implications for various sectors reliant on the ocean environment.

Ocean current circulation modeling in the Bengkalis Strait in the east spring

The waters of the Bengkalis Strait are geographically very strategic, directly connected to the waters of the Malacca Strait and a strategic water transportation route. One of the complex phenomena that appears in the waters of the Bengkalis Strait is the phenomenon of current movement. This survey was conducted from June to August 2022. The survey location was in the Bengkalis Strait, Bengkalis Regency, Riau Province. The research aims to determine current patterns and sea level height during the highest tides and lowest low tides each month during the east season in the waters of the Bengkalis Strait. The method used is a Survey and a quantitative descriptive method. All data is processed using MIKE 21 software. First, Google Earth was used to create bathymetry data, and then the boundaries of the survey area were determined using MIKE 21. After obtaining the bathymetry, we continued with the flow model using MIKE 21 and then displayed the results. Obtained results: the highest tide occurred on 13/06/2022 at 13:00 WIB with an average current discharge of 0.14-0.16 m/s, and the lowest wave occurred on 13/06/2022 at 20.00 WIB with an average flow rate of 0.60-0.75 m/s

Shadow zone mapping using parabolic equation method in the Bali Strait Waters

Shadow Zone is an area where sound waves cannot penetrate a water column due to deflection. This study aims to map the shadow zone based on oceanographic parameters in the Bali Strait. The data used are temperature, salinity, and depth for 31 days in the East Season (July) in the Bali Strait at two stations from the results of numerical modeling downloaded from the website https://marine.copernicus.eu/. Shadow zone simulation uses the parabolic equation method with certain parameter limits. The vertical temperature profile shows that the deeper the water is, the lower the temperature, whereas salinity is the opposite. The sound velocity is affected by the parameters of temperature and salinity. At the location of the 25 m transducers, the undetected medium beam is narrower than the location of the 110 m transducers so that the shadow zone with a 110 m transducer position has a broader area. The Shadow zone area in the northern Bali Strait is effectively detected using a frequency of 100 Hz. In comparison, in the southern part of the Bali Strait, it is effectively seen at a frequency of 38 Hz, with the respective transducer positions used at a depth of 25 and 110 m.

STUDY OF DIKE EFFECTS TO CONTROL SEDIMENTATION PROCESS ON PATIMBAN'S PORT PLAN USING COMPUTATION MODELING

The development of the international port of Patimban in Subang is very urgent. The port is expected to support the Tanjung Priok port in Jakarta which is unable to meet the loading and unloading needs of business operators, especially in West Java. In port development planning one of the main problems of physical chemical aspects is sedimentation and erosion process. The purpose of this modeling is to know the sedimentation and erosion pattern around the location plan of port development. The result of modeling is expected to be the initial consideration in designing the Patimban Port. Modeling of sediment transport is done by using MIKE21 Sand Transport module software by entering geophysical data of field survey result such as bathymetry, sea level, river flow and characteristic of existing sediment. Modeling is done both in west season and east season for 1 year (October 2016-September 2017). Based on the result of point extraction on the modeling result, it is known that the influence of dike significantly reduces the bed level change in the harbor channel about 46.45 - 82.28% (for dike 2 m) and about 55.01 - 88.94% (for dike 4 m). While, based on the result of the area extraction, it is known that the influence of the dike on the bed level change in the harbor channel is significant, that is to decrease the average of bed level change by 77.58% (for dike 2m) and 81.02% (for dike 4m).

Kajian Karakteristik Gelombang Laut di Wilayah Pantai Pulau Merah, Kabupaten Banyuwangi


 
 
 
 Sea wave parameter information is used in maritime-related activities such as sea transportation, offshore exploration, fisheries, port construction, shipping safety, coastal area development, and coastal mitigation. This study described the characteristics of the sea waves in Pulau Merah Beach, Banyuwangi Regency. Wind reanalysis data of 10 meters was processed using the Sverdrup Munk Bretschneider (SMB) method using the Easywave algorithm. The analyzed and processed the sea wave model's assimilation data from Marine Copernicus pointwise by WRPLOT. The results of wind and ocean wave data processing showed that the direction, height, and period of sea waves on Pulau Merah Beach are strongly influenced by the Monsoon Wind. The sea wave height in the Pulau Merah Beach region reaches its peak value during the East season, which is 1.5 meters. In contrast, the value of the period of sea waves in the Pulau Merah Beach area reached its peak value during the Transitional Season I period, which was 8.3 seconds.
 
 
 

Seasonal hydrodynamic pattern and effect of marine sediment distribution in Banten Bay

This study aimed to see the pattern of current velocity and direction at the time of high tide, high tide, low tide, and lowest low tide during the west and east monsoons as well as to see an increase in sedimentation. Oceanographic and environmental baseline data used in this study consisted of bathymetry, tides, winds, waves, ocean currents, and sediment. The model used was DHI MIKE 21 Flow Model FM. Based on the calculation of determining the type of tide using the Formzahl formulation 1.54, the tides in the study area were classified as single dominant mixed tides. In the west season, the maximum current velocity was 0.112 m/s with the dominant current direction coming from the northeast to the southwest and approaching the coast. In the east season, the maximum current velocity was 0.112 m/s with the dominant current direction coming from the northeast to the southwest and approaching the coast. The highest concentration of suspended sediment in December was when the seawater conditions were nearing low tide. The highest concentration of suspended sediment was in the eastern part of Pier 3 at 1120 g/m3. The most significant change in bed level in December was at Pier 3 on the east side where the elevation increase was +0.30 m and the elevation decrease was -0.40 m. From the information regarding the location of the abrasion and sedimentation of the jetty development, it is possible to know in advance the anticipation of the dredging plan and the mitigation of coastal abrasion.

Temperature, Salinity and Dissolved Oxygen West and East seasons in the waters of Amurang Bay, North Sulawesi

Observations of temperature, salinity, and dissolved oxygen have been carried out in Amurang Bay waters, North Sulawesi. This study aims to determine the temperature, salinity, and dissolved oxygen during the west and east seasonal monsoons. The statistical analysis results using the t-test showed that the temperature, salinity, and dissolved oxygen in the West monsoon with the east monsoon were significantly different. Temperature, salinity, and dissolved oxygen in the west monsoon are lower than in the east. Variations in temperature, salinity, and dissolved oxygen are influenced by atmospheric conditions, weather, rainfall, and current patterns. Implicitly, temperature and salinity can affect the solubility of oxygen in the East monsoon. The value of AOU (Apparent Oxygen Utilization) in the west monsoon is less than 0.00 mg/l (negative), which indicates that oxygen is very much needed for the process of respiration and decomposition of organic substances during the west monsoon.
 Keywords: oceanographic conditions, temperature, salinity, dissolved oxygen, Amurang Bay.

Opak and Bogowonto Coastal Inlet Sand Spit Morphodynamics using Landsat and Sentinel Satellite Images

Sand spits are elongated sand deposits on the beach that often form at the inlet or the headland’s tip. The hydrodynamics of the river flow, waves, storm surge, and tide affect the sand spit formation, which was created by the longshore transport along the coast. Bogowonto and Opak inlets are located in southern coastal Java facing directly to the Indian ocean where micro-tidal, waves, and river flow affecting both inlets, are chosen for this case study. Morphodynamics analysis of sand spit using Landsat 7 and 8, Sentinel 2 image from 2000 to 2020, coastline identification using Modified Normalized Different Water Index (mNDWI). In November 2007 and October 2013, Opak Inlet migratory routes were detected, and closures related to the east season occurred at both of them. Inlet tend to close occur on east season during July until November.

Spesies Composition and Bycatch from Gombang in East and South Seasons in Bengkalis, Riau, Indonesia

Gombang is one of the stationary fishing gear used in the coastal waters of Bengkalis. The gear is grouped as trap fishing gear and operated based on the fishing seasons, namely east, west and south seasons. This study at to determine the composition of the main catch, bycatch, and discards of this filtering net gear. The survey was conducted directly in the field, to identify of composition catches during April – September 2019. The catches were classified as main catch, bycatch, and discard. The results of this study showed that the total catch consisted of 35 species. The highest percentage of catch was scored as bycatch during east season (77.7%) with 27 species and during the south season (73.3%) with 26 species. The main catch percentage was 17.1% with six species’ during the east and south seasons. The rest was the discard (5.7%) consisting of 2 species during the east season, and 3 species (8.6%) during the south season. The present study revealed that quantities of bycatch during the west season were relatively higher than the main catch and discard.