Skipjack Tuna Thrive in Cooler Pangandaran Waters During Southeast Monsoon
Researchers from Universitas Padjadjaran have identified seasonal sea surface temperature patterns that help determine the most suitable fishing periods for skipjack tuna in Pangandaran waters, offering new guidance for Indonesia’s small-scale fisheries sector. The study, published in 2026 in the International Journal of Contemporary Sciences, found that cooler ocean temperatures linked to seasonal upwelling create more favorable habitats for skipjack tuna, particularly during the southeast monsoon.
The research was conducted by Gilar Budi Pratama and Aisyah from the Department of Fisheries, Faculty of Fisheries and Marine Sciences at Universitas Padjadjaran. Their findings are considered important because skipjack tuna remains one of Indonesia’s most economically valuable pelagic fish species and a major source of income for coastal communities.
According to the researchers, understanding sea surface temperature trends can help fishers identify more productive fishing grounds while reducing fuel costs and operational uncertainty. The findings may also strengthen sustainable fisheries management in southern Java waters.
Why Sea Surface Temperature Matters
Indonesia’s small-scale fisheries contribute significantly to domestic food security and coastal livelihoods. In Pangandaran, many fishers depend on skipjack tuna, scientifically known as Katsuwonus pelamis, for daily income.
However, locating productive fishing grounds remains challenging because fish distribution changes constantly in response to oceanographic conditions. One of the most important environmental indicators is sea surface temperature, often abbreviated as SST.
The study explains that SST affects fish metabolism, feeding behavior, migration, and prey availability. Cooler waters associated with nutrient-rich upwelling zones tend to stimulate plankton growth, creating favorable feeding conditions for pelagic fish species such as skipjack tuna.
Previous studies cited by the researchers suggest skipjack tuna generally prefer waters between 27°C and 29°C, with around 28°C considered highly suitable for biological activity and feeding.
Mapping Ocean Temperatures Across 2024
To analyze fishing suitability, the research team examined monthly sea surface temperature data in Pangandaran waters from January to December 2024.
The data came from the Copernicus Marine Service Global Ocean Physics Reanalysis system, which combines satellite observations and direct ocean measurements. The researchers used monthly raster-based oceanographic data with a spatial resolution of 0.083 degrees to track temperature changes throughout the year.
Instead of focusing directly on fish catch volumes, the study compared observed sea temperatures with previously established optimal temperature ranges for skipjack tuna habitat.
The researchers then created spatial maps showing which parts of Pangandaran waters were considered suitable or unsuitable during different months of 2024.
Key Findings From the Study
The study revealed strong seasonal temperature variability in Pangandaran waters.
Key findings include:
- Sea surface temperatures ranged from 26.21°C to 30.02°C throughout 2024.
- The warmest conditions occurred in February, reaching an average of 30.02°C.
- The coolest conditions appeared in August, when temperatures dropped to 26.21°C.
- Suitable temperature conditions for skipjack tuna were mainly found in January, May, July, and August.
- The southeast monsoon created the most productive conditions due to upwelling processes that cooled surface waters and increased marine productivity.
The research also showed that ocean temperatures during July and August were especially favorable for skipjack tuna distribution. During this period, suitable thermal conditions expanded from coastal waters toward offshore areas.
In contrast, conditions during late 2024 were generally less suitable because warmer waters dominated much of the study area.
The researchers linked these patterns to monsoon-driven oceanographic dynamics in southern Java waters. During the southeast monsoon, colder nutrient-rich waters rise to the surface, increasing biological productivity and supporting the marine food chain.
Seasonal Fishing Insights for Small-Scale Fishers
The study highlights how seasonal ocean changes directly influence fishing opportunities for coastal communities.
During the northwest monsoon at the beginning and end of the year, warmer waters create more stable but less productive conditions. Meanwhile, the southeast monsoon supports richer marine ecosystems that attract pelagic fish.
The authors noted that excessively warm surface temperatures may force fish into deeper waters, making them harder to catch with traditional small-scale fishing gear.
“Suitable temperature ranges for skipjack were generally observed during specific periods, particularly in January, May, July, and August,” the researchers from Universitas Padjadjaran explained in the study.
The research also confirms earlier findings that peak skipjack fishing seasons in the Indian Ocean often coincide with southeast monsoon conditions.
Implications for Fisheries Management
The findings could help improve operational planning for Indonesia’s small-scale fisheries sector.
By using sea surface temperature maps, fishers may be able to:
- Reduce time spent searching for fishing grounds
- Lower fuel consumption and operational costs
- Improve fishing efficiency
- Minimize environmental pressure caused by excessive searching activity
The research also supports broader efforts toward sustainable fisheries management by promoting data-driven decision-making.
However, the authors emphasized that sea surface temperature alone cannot fully predict fish distribution. Other factors such as chlorophyll-a concentration, ocean currents, food availability, and marine productivity must also be considered.
Future studies are expected to combine satellite oceanography, real-time fisheries data, and machine learning models to develop more accurate fishing ground prediction systems.
The researchers also recommended studying climate phenomena such as the El Niño–Southern Oscillation and the Indian Ocean Dipole because these large-scale climate systems may strongly influence fish migration and ocean productivity in Indonesian waters.
Author Profile
Gilar Budi Pratama is a fisheries and marine science researcher from the Department of Fisheries, Faculty of Fisheries and Marine Sciences at Universitas Padjadjaran. His expertise focuses on fisheries oceanography, pelagic fish distribution, and oceanographic modeling for sustainable fisheries management.
Aisyah is affiliated with the same department and conducts research related to fisheries management and marine environmental analysis.
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