areas along and north of the Equator, it appears that different age groups occur south of 6 S. 

 latitude and in the vicinity of the Equator. Furthermore, as was noted earlier, south of 6 S. 

 latitude there are wider fluctuations in the catch rates and a more unstable fishing situation than 

 along the Equator or to the north of it. 



Although there are these differences in the character of the fishing grounds in 

 different parts of the area, it is recognized that the waters off western Sumatra are excellent 

 fishing grounds during the season when the northeasterly winds are at their strongest. The signi- 

 fic3ince of the area as a fishing ground during the season of southwesterly winds is not clear. 



3. Waters off Java (6° to 13° S., 105° to 1 15° E. ) 



The sea area between the Sunda Strait and the Lombok Strziit is that referred to here 

 as the waters off Java. During the season of southerly winds the sea currents in this ajrea. are 

 quite simple, with the current which runs along the south coast of the Lesser Sunda archipelago, 

 which lies immediately to the east of Java, simply continuing to flow westward along the south 

 coast of Java. The velocity of this current is rather high, speeds of 1 knot per hour or more 

 having been recorded. A pronounced current boundary appears running southwestward from the 

 vicinity of the Sunda Strait and the coastal waters of Sumatra to the north of this boundary form 

 a completely distinct water system. 



From Jsmuatry through March, when the northerly winds blow continuously, the 

 pattern of the sea currents changes completely and becomes remarkably complex. To describe 

 them in a rough outline, there is a conspicuous current boundary trending generally east and 

 west in the vicinity of 8 to 10 S. latitude, and this boundary turns to the southwestward in the 

 vicinity of Lombok Strait at the eastern extremity of this sea area. On the south side of this 

 boundary the currents flow generally westward. The current coming south off the coast of 

 Sumatra turns and flows to the eastward. The current on the north side of the boundary is pressed 

 in very close to the shores of Java by currents on its south side aind its velocity is high although 

 the current itself is extremely narrow. The currents on the south side of the boundary come out 

 of the central part of the southern Indian Ocean flowing to the northeastward, and impinging upon 

 the island of Java they turn to the west. To the east of the current boundary in the vicinity of 

 Lombok Strait, the current flowing north along the west coast of Australia turns to the northeaist 

 and thereafter turns eastwcird to flow along the Lesser Sunda archipelago. 



As indicated by the above brief description, during the season when northerly winds 

 predominate, the coastal waters of Java are almost completely cut off from and are under the 

 influence of different currents from the adjacent sea areas to the east and the northwest. 



Sea conditions in the season of southerly winds are unknown because there are no 

 data. During the season of prevailing northerlies surface water temperatures in this sea area 

 are not greatly different fronn those of the west coast waters of Sunnatra, but the temperatures at 

 the 50-meter and 200-meter levels seem to be rather markedly lower. 



The season of southerly winds is the rainy season in this sea area and the weather.is 

 bad and the sea rough. Furthermore, typhoons occur from time to tinne amd it is thought that 

 interference with operations by the weather will be frequent. During the season of northerly 

 winds there is continuous good weather, the sea is extremely calm, and operating should be easy. 



Data on past investigations in this sea area are available only from the Hakuyo Maru 

 and the Haruna Maru. Investigations of the Haruna Maru were carried on during December 1933, 

 ajid the area investigated was limited to the eastern and western extremes of this sea area, that 

 is, the vicinities of the Lombok and Sunda straits. The explorations of the Hakuyo Meiru were 

 carried out in June 1926 and were scattered throughout this whole area. These data have been 

 brought together to show the fishing conditions in the waters of Java in the following table. 



48 



