Volume, heat and freshwater transports from the South China Sea (SCS) to the Java Sea through the Karimata Strait are estimated based on direct measurements of current, temperature, salinity, and satellite observations. Subject to strong seasonal variability, the volume, heat, freshwater transports

Global ocean circulation is a primary mechanism for transporting energy and nutrients around the planet. At its most basic level, this circulation transports water from the Pacific Ocean through the Indonesian archipelago into the Indian Ocean; these waters join the Agulhas Current, which loops around Africa and in turn joins the Gulf Stream in the Atlantic Ocean. Upon reaching the North Atlantic, waters sink, creep south along the ocean floor as deep water, trace around Antarctica as bottom water, and move to the Pacific Ocean where they upwell, only to seep back into the Indian Ocean through the straits and channels surrounding Indonesia. The seepage of warm equatorial waters from the western Pacific Ocean into the Indian Ocean is called the Indonesian Throughflow (ITF). Long recognized as a key component of global ocean circulation, the ITF's magnitude and variability play an important role in determining heat and nutrient exchange to other ocean basins. Scientists' ability to estimate ITF behavior is therefore essential for understanding the global climate system.

Spatial distribution of tuna (Thunnus.sp) in Indian Ocean south of Java has been investigated. Tuna was scientifically known as thermo-conformer species, thus their distribution were strongly influenced by sub-surface temperature. Tuna species in this study comprise of bigeye tuna (Thunnus obesus), albacore tuna (Thunnus alalunga), yellowfin tuna (Thunnus albacares) and southern bluefin tuna (Thunnus maccoyii). The study was conducted in the area between 100 o E -127 o E and 7 o S -20 o S during 2013 covering of southeast monsoon (April -September) and northwest monsoon (October -March) data. About 1200 coordinate of ARGO Float data and actual catch of tuna from fishing fleet in the same day were processed to obtain the polynomial equation and correlation coefficient. ARGO Float data were processed using kriging method. Correlation coefficient method that used in the study was Empirical Cumulative Distribution Function (ECDF), while spatial distribution equation was developed by polynomial regression equation. Sub-surface temperature in Indian Ocean south of Java fluctuates seasonally. Temporal distribution of dataset indicates that sub-surface temperature was warmer in northwest monsoon than in southeast monsoon. Seasonal fluctuation of sub-surface temperature may vary due to occurrence of upwelling. T. alalunga, T. Albacares and T. Obesus were found to be more favour in the depth around 150m with optimum temperature between 16 o C -21 o C, while T. maccoyii were found in the dept around 250m with optimum temperature between 13 o C -16 o C. Potential fishing zone for Thunnus.sp in southeast monsoon was wider than in northwest monsoon. This condition was according to seasonal variability of sub-surface temperature.