The extracts in the demijohns and drmns were used either as prepared 

 or they were diluted to various stren^^ths on board ship. The frozen material 

 was thawed and extracted with sea water on board ship for at least 1 hour before 

 use. 



In addition to the above, two tests were performed with anchovy extract 

 prepared on board by crushing the live bait in buckets of water, allowing the 

 preparation to settle, and then decanting the supernatant liquid. 



Methods of Testing 



The methods of testing the response of sea fish to the extracts were 

 many and varied. In some cases the extract was poured from buckets from the 

 side or stern of the ship as it described an arc or circle near or around a flock 

 of birds and, presumably, a school of tuna. In the majority of the tests, the 

 'tuna school was attracted to the stern with live bait, chumming was stopped, and 

 the extract was poured over the stern into the group of feeding fish. In others, 

 when chumming ceased, the extract was poured in varied quantities and dilutions 

 from the port and/or starboard sides forward of amidships. In still others. It 

 was pumped in a stream or spray from amidships; the pump was controlled from the 

 flying bridge where the fish could be seen. 



Hesults 



In all, 16 tests were performed with skipjack or yellowfln extract and 

 2 with anchovy extract, with several trials per test in some cases. The tests 

 were performed mostly on schools of skipjack or on mixed schools of skipjack and 

 yellowfln, skipjack and tunny, or skipjack and frigate mackerel. In addition 

 two tests were conducted on a pure school of frigate mackerel and one on a school 

 of dolphin. 



The results were either negative or inconclusive. Unchummed schools 

 could not be raised by an arc or circle of extract. Chummed schools could not be 

 held at the stern by Introducing the extract in small quantities by either bucket 

 or pump. 



In a few tests, on pouring In a large quantity of extract after the 

 school had been chummed to the stern and chumming was stopped, a few fish were 

 seen jumping in or passing through the material. It could not be determined 

 whether they were responding to the extract or were chasing stray baitfish. The 

 latter seems to be the more likely explanation. 



Discuaslon 



In view of the results outlined above, and others to be reported below 

 In which extracts were used in combination with edible lures, it may be concluded 

 with reasonable certainty that the local skipjack will not respond to extracts 

 of skipjack viscera, yellowfln flesh, and anchovy. It seems likely that this 

 conclusion also applies to local tunny and yellowfln, which showed a response in 

 the pond but not at sea. However, the sea tests on tunny and yellowfln were few 

 In number and were conducted on schools in which they were mixed with skipjack. 

 There is the possibility that they might respond to the extracts if schooled 

 alone. 



No sea tests were conducted with extracts of squid and shrimp, both of 

 which might be considered to be a more natural food than skipjack, yellowfln, or 

 ancnovy, and therefore might be expected to elicit a response even though the 

 other materials failed. There wei-e several reasons for not using extracts of 

 squid and shrimp. Including the lesser availability and higher cost of these 

 materials. The chief reason was that the pond fish had responded well to tuna 

 flesh extracts even though they had been fed exclusively on squid for a period 

 of 2 months. This indicated that they had not been conditioned to any particular 

 food item, but rather were responding to an "attractant" which was generally dis- 

 tributed throughout all food Items. It was assumed that this might also be the 

 case with the fish in their natural environment, and that If they responded at 

 all, they would respond (almost) equally well to extracts of tuna, anchovy, 

 shrimp, squid, etc. 



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