Hubungan IOD-ENSO Terhadap SPL, Klorofil-a dan Hasil Tangkapan Ikan Pelagis di Perairan Selatan Jawa /The Relationship Between IOD-ENSO to SST, Chlorophyll-a and Pelagic Fish Catches in the Waters of Southern Java

Abstract

Kondisi oseanografi di Perairan Selatan Jawa sangat dipengaruhi oleh sistem angin monsun dan fenomena iklim global seperti Indian Ocean Dipole (IOD) dan El Niño-Southern Oscillation (ENSO). Penelitian ini bertujuan untuk menganalisis distribusi spasial dan temporal suhu permukaan laut (SPL) dan konsentrasi klorofil-a, pengaruh fenomena iklim global terhadap SPL, konsentrasi klorofil-a dan hasil tangkapan ikan cakalang dan ikan kembung di Perairan Selatan Jawa selama periode 2014 – 2022. Data yang digunakan meliputi data citra SPL dengan resolusi 4 km diperoleh dari website Ocean Color. Data citra klorofil-a dengan resolusi 4 km diperoleh dari website Marine Copernicus. Data indeks iklim bulanan Dipole Mode Index (DMI) dan NINO3.4 diperoleh dari website National Oceanic and Atmospheric Administration (NOAA). Data hasil tangkapan ikan cakalang dan ikan kembung diperoleh dari Pelabuhan Perikanan Nusantara (PPN) Palabuhanratu, Pelabuhan Perikanan Samudera (PPS) Cilacap, dan Pelabuhan Perikanan Nusantara (PPN) Prigi. Metode Emphirical Orthogonal Function (EOF) digunakan untuk menganalisis variabilitas spasial, analisis korelasi silang digunakan untuk menganalisis hubungan antara variabilitas SPL, konsentrasi klorofil-a terhadap hasil tangkapan ikan serta analisis korelasi Pearson digunakan untuk menguji hubungan dengan DMI dan NINO3.4. Hasil penelitian menunjukkan distribusi spasial SPL terendah dan klorofil-a tertinggi terjadi di sepanjang wilayah pesisir pada puncak monsun tenggara akibat adanya upwelling. Hasil analisis EOF mode 1 menunjukkan adanya variabilitas musiman yang mendominasi dinamika perairan dengan kontribusi varians mencapai 96.53. Hasil korelasi silang menunjukkan pola temporal perairan dipengaruhi secara kuat oleh fenomena interannual IOD, dibandingkan El Niño. Pengaruh IOD positif cukup kuat pada tahun 2015, ditandai oleh penurunan SPL dan peningkatan konsentrasi klorofil-a sehingga memicu peningkatan pada hasil tangkapan ikan cakalang dan ikan kembung.

The oceanographic conditions of Southern Java are strongly influenced by the monsoon wind system and global climate phenomena, such as the Indian Ocean Dipole (IOD) and El Niño-Southern Oscillation (ENSO). This study analyzes the spatial and temporal distribution of sea surface temperature (SST) and chlorophyll-a concentration, and the effect of global climate phenomena on SST, chlorophyll-a concentration, and the catch rates of skipjack tuna and mackerel in Southern Java from 2014 to 2022. SST imagery at 4 km resolution was obtained from the Ocean Color Website, while chlorophyll-a imagery at the same resolution was obtained from the Marine Copernicus website. Monthly Dipole Mode Indes (DMI) and NINO3.4 climate index data were collected from the NOAA website. Catch data for skipjack tuna and mackerel were obtained from Palabuhanratu, Cilacap, and Prigi Fisheries Port Authorities. The Emphirical Orthogonal Function (EOF) method was used to analyze spatial variability, cross-correlation analysis was applied to examine the relationship between SST and chlorophyll-a variability and fish catches, and Pearson correlation analysis was used to assess their relationships with the DMI and NINO3.4 indices. The findings indicate that the lowest SST and highest chlorophyll-a concentrations occur along the coast at the peak of the southeast monsoon, a pattern attributed to upwelling. EOF Mode 1 analysis revealed that seasonal variability dominates the dynamics of these waters, accounting for 96.53% of the variance. Cross-correlation results indicate that the temporal variability of the waters was more strongly associated with interannual IOD variability than with El Niño. The influence of positive IOD was particularly evident in 2015, characterized by decreased SST and increased chlorophyll-a concentration, which subsequently contributed to increased catches of skipjack tuna and mackerel.