East Season Research Articles

FACTORS INFLUENCING THE WELFARE OF RAJUANGAN FISHERMEN IN THE EASTERN COASTAL WATERS OF LAMPUNG PROVINCE

The objective of this study is to identify the factors influencing the welfare of blue swimming crab fishermen in the eastern coastal region of Lampung Province. The study was conducted in three regencies: East Lampung, Central Lampung, and Tulang Bawang, with a sample of 100 blue swimming crab fishermen. Daily fishermen use boats with a capacity of 1-2 GT, while babangan fishermen use boats with a capacity of more than 2 GT. The average catch for daily fishermen ranges from 1.99 to 3.18 kg per trip during the east season and from 9.08 to 10.33 kg per trip during the west season. Babangan fishermen catch an average of 74 kg per trip during the east season and 222 kg per trip during the west season. The factors influencing the welfare of fishermen during the east season are income level (X1), number of family dependents (X4), housing conditions (D1), ease of access to education (D3), and ease of access to transportation (D4). During the west season, the influencing factors are income level (X1), education level (X3), number of family dependents (X4), age of the head of the family (X5), ease of access to healthcare services (D2), and ease of access to education (D3).

Analysis of Waters Physical Condition in Small Pelagic Fishing Location (Case Study at Fisheries Management Area (FMA) 715)

The aim of research is to study the physical conditions at the small pelagic fishing locations relation with the ideal criteria for small pelagic fish habitat. In this research, physical parameters consist of temperature and chlorophyll-a will be analyzed according to conditions at the actual small pelagic fishing location in FMA 715 throughout 2018. The actual small pelagic fishing location is obtained from the fishing logbook data which is validated with the Vessel Monitoring System (VMS) data using Kernel Density Interpolation. Sea surface temperature (SST) and chlorophyll-a information at small pelagic fishing locations are extracted through MODIS Imagery. Small pelagic fish species at the fishing location are caught for Shortfin Scad, Trevally, Yellowstrip Scad, and Shadow Trevally. The results showed that the surface temperature at the small pelagic fishing location in FMA 715 is 21.56 - 31.75 oC and chlorophyll-a concentration is 0.08 - 1.33 mg/m3. It can be concluded that the physical conditions at the small pelagic fishing location are not always in accordance with the ideal habitat conditions. The conditions of sea surface temperature and chlorophyll-a that are close to the ideal conditions for small pelagic fish habitat are in the East Season.

Morphodynamic Cartography Visualization of Wulan River Estuary Systems from Space to Numerical Approach Based on Multi-Season Analysis

This research aims to investigate the morphodynamics of the Wulan River estuary in Demak Regency using the integration of multispectral remote sensing images and numerical modeling. In this study, PlanetScope for a manualvisual analysis of estuary morphodynamics and Sentinel-2 MSI Level 2A to obtain periodic total suspended solids (TSS) information for the east and west monsoon seasons. MIKE by DHI software used to develop hydrodynamic numerical modeling in order to characterize the current circulation and sediment transport model. Based on a marine cartography aspect, the obtained results illustrated that the climatological phenomenon of seasonal forcing plays a role in the development of the current circulation and indirectly influences the sediment transport. During the west season, the morphodynamics in the Wulan River estuary are much more massive and significant as compared to the east season. A projection of the deposition that results from the sediment transport is described in the bed-thickness change; this occurs in the western part of the Wulan River estuary during the east season, while the bed-thickness change occurs predominantly in the northern part during the west season (where there was previously a beach sandbar phenomenon). This was verified through multi-temporal satellite imagery that the deposition that occurs in the northern part of the Wulan River estuary during the west season is increasingly progressive and massive.

Mapping the distribution of stingray fishing grounds in the south west waters of Aceh during the east season

Mapping the distribution of stingray fishing grounds in the south west waters of Aceh during the east season

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.

Dynamics of Coral Fish Biomass in The Coastal Waters of Spelman Strait, Central Buton Regency, Southeast Sulawesi

The coastal waters of the Spelman Strait are rich in reef fish resources. Small-scale fishers also use coral fishing in the coastal waters of the Spelman Strait in meeting household needs and improving their welfare. The purpose of this research is to analyze how coral fish biomass in two fishing seasons, namely the west and east seasons. The coastal waters of the Spelman Strait are rich in reef fish resources. Small-scale fishers also use coral fishing in the coastal waters of the Spelman Strait in meeting household needs and improving their welfare. The purpose of this research is to analyze how coral fish biomass in two fishing seasons, namely the west and east seasons. The results of the study, reef fish biomass in the two seasons is relatively different. The difference between the two is due to different fishing patterns, wherein the wet season, the reef fish that are targeted by fishermen are the Serranidae and Lutjanidae families, and the size of the fish is relatively large by using hooks number 5, 6, 7 and 8. In contrast, in the east season, the target fish fishers are all reef fishes and are relatively small in size using hooks 15, 16 and 17. The problem is that some fishermen still use explosives in catching reef fish. Muis et al. (2019) reported the condition of live coral cover in the coastal waters of the Spelman Strait in moderate condition (37.71) and dead coral (33.71). Community participation in the management of fisheries resources is significant to note because the community is the user of these resources. Community participation in the management of fisheries resources is crucial to do because of fishermen as users of resources. Muis et al. (2019) reported the condition of live coral cover in the coastal waters of the Spelman Strait in moderate condition (37.71) and dead coral (33.71).

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).

Chlorophyl-a Distribution and Sea Surface Temprature Using Modis Aqua Image Data in Bone Bay Waters

ABSTRACTOne of the parameters determining productivity in the sea is chlorophyll-a. The fertility level of chlorophyll-a is closely related to the concentration of chlorophyll-a. The higher the concentration of chlorophyll-a, the higher the water fertility level, conversely, if chlorophyll-a is low, the water fertility level will also be low. One factor influencing growth rate and chlorophyll-a production is temperature. This research aimed to determine the distribution of chlorophyll-a and sea surface temperature based on season in 2022 in the waters of Bone Bay using quantitative descriptive method and geographic information analysis (GIS) procedure in the form of analysis of Aqua MODIS remote sensing image data. The research results showed that the highest distribution of chlorophyll-a occurred in the east season with a concentration of 0.06-2.04 mg/m³, while the lowest distribution of chlorophyll-a occurred in the west season with a concentration of 0.07-1.76 mg/m³. Meanwhile, the highest intensity sea surface temperature distribution occurred in the west season, which was 28.76-37.09 °C and the lowest sea surface temperature distribution fell in the east season, which was 27.13-33.62 °C. Spatial temperature variability and sea surface chlorophyll-a can be used as information about potential areas for fishing grounds.Key words: chlorophyll-a distribution, sea surface temperature, Bone Bay, Aqua MODIS

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.