Dolphin, on the other hand, were successfully established in 

 pond Noo Ij without the use of night illumination. When introduced, 

 these fish swam slowly and leisurely at or close to the surface, 

 creating a "bow-wave" as they travelledn They tended to avoid the 

 sides and to keep to the center of the pondo They were encouraged in 

 this tendency by placing a floating board,, held by a line and anchors, 

 near the middle--at sea, they are frequently observed to slowly circle 

 a floating logs, board, or coconut frondo The fish started to feed on 

 strips of tuna flesh within a few days after they were placed in the 

 pond. After starting to feed, they became quite "tame'* and would mill 

 around close to shore at the approach of an observer^ expecting to be 

 fed. They fed voraciously on tuna fleshy dead nehu ( Stolephorus 

 purpureus ) , and dead iao ( Pranesus insularum ), entering into rather 

 unsuccessful competition with several jacks which were also present in 

 the pondo They would also feed on schools of live nehu and iao which 

 entered occasionally through the screened gateso 



Despite the successful establishment of dolphin, mortality 

 was higho A few died from injuries sustained during capture and 

 transportation before they started to feedo Others came in contact 

 with the rough coral walls during feedings and died from injuries 

 mostly to the head and jawso Over the period April 10 to June 27s, 26 

 fish had been placed in the pond and there were 14 survivorso No 

 more were introduced until August 8 when there were 6 of the 14 still 

 aliveo Throughout August, September, and October the number was 

 maintained at about five or six by adding one or two fish per montho 

 No particular effort was made to build up a large population, as the 

 fish were not being used for experimental purposeso At the time of 

 writing (October 20j, 1951), five fish were present, three of which had 

 been living in the pond for at least 4 months,, 



The two jacks caught by trolling were placed in the pond on 

 May 24 and October 18 respectively^. Both have become establishedo 



Concrete Tank 



In the next attempt to establish tunap a large rectangular 

 concrete tank was used (figo 5)o The tank, partially sunk in the 

 groundj was made of smooth, 6-inch concrete walls and bottom, and on 

 the inside measured 34c, 7 feet long, 10„8 feet wide,, and 3o8 feet deep 

 at the north end and 4o0 feet deep at the south end. Its volume was 

 10,663 gallons o Running salt water was supplied by a pump at the rate 

 of about 25 gallons per minuteo The inlet, near the northwest corner, 

 was directed horizontally (towards the south) at a depth of about 2^ 

 feet to promote circulation,, The outlet was a notch cut in the top 

 of the south wall at its centero Baffles,, consisting of 3 x 4-foot 

 galvanized iron sheets,, painted white, were placed across the four 

 comers. It is believed that these played an important part in the 

 eventual establishment of the tuna, giving them reference points to 

 mark the limits of the tank during the period of adjustment,. The 

 baffle in the northeast corner was later replaced by a larger one 

 (3 X 10 feet), behind which was installed equipment for testing the 



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