by 0600 and in 83 percent by 0700. On those 

 trips where scouting started after 0700, the 

 vessels usually spent part of the morning 

 catching bait. Scouting continued until sunset, 

 but rough weather, mechanical trouble, the need 

 to unload the catch before spoilage, or the need 

 to replenish the baitwells curtailed some trips. 

 Scouting ended between 1700 and 1900 in 60 

 percent of the trips; most (36 percent) ended at 

 1801-1900. 



Fishermen have long been aware of the asso- 

 ciation of sea birds with schools of fish. In 

 Hawaii, the fishermen locate fish schools by 

 relying almost exclusively on birds, large num- 

 bers of which flock and feed on prey driven to 

 the surface by the skipjack tuna. Among the 

 birds most frequently associated with fish 

 schools are sooty tern. Sterna fuscata ; noddy 

 tern, Anous stolidus ; wedge-tailed shearwater, 

 Puffinus pacificus ; and petrel, family Procel- 

 lariidae, subfamily Hydrobatinae. In addition, 

 other species which usually do not flock, but 

 frequently associate with fish schools are the 

 great frigate bird, F regata minor; boobies, 

 Sula spp.; and bo'sun (tropic birds), Phaethon 

 spp. 



In this report, we make the assumption that a 

 fish school was associated with each bird flock 

 sighted. This assumption appears justified. 

 On two scouting cruises of the research vessel, 

 Charles E_. Gilbert , during the spring of 1953, 

 Royce and Otsu (1955) found that "every one of 

 253 fish schools sighted was accompanied by 

 birds and was found by means of birds." Al- 

 though no mention is made of the number of 

 flocks not associated with fish schools, we be- 

 lieve that most of the flocks sighted are asso- 

 ciated with fish schools, because the fishermen 

 can usually distinguish by observing the birds' 

 behavior whether a school is nearby. Numbers 

 of birds flying together in the same direction 

 and not quartering back and forth or diving are 

 usually regarded as scattered birds. 



Bird flock sightings on 231 trips totaled 1,249 

 flocks or an average of 5.4 schools per trip. 

 Vessel B, sighting 158 schools on 36 trips, 

 averaged the least, with 4.4 schools per trip, 

 whereas vessel E, sighting 320 schools on 51 

 trips, averaged the most, with 6.3 schools per 

 trip (table 3). Trips with no sightings reached 

 2 percent. From the data in table 4 and figure 

 5, we found that 5 schools were sighted on one 



Table 2. — Number and percentage of trips tabulated by time the vessels departed, 

 started and ended scouting, and returned to port, Hawaii, June-August 1967 



Time 



Departure 



Scouting 

 started 



Scouting 

 ended 



Returned 

 to port 





Number 



Percent 



Number 



Percent 



Number 



Percent 



Number 



Percent 



0001-0100 



9 



3. 



7 











9 



3.8 



0101-0200 



10 



4. 



1 











7 



3.0 



0201-0300 



31 



12. 



8 











2 



0.8 



0301-0400 



27 



11. 



1 











4 



1.7 



0401-0500 



37 



15. 



2 



6 



2.5 







1 



0.4 



0501-0600 



99 



40. 



7 



117 



48.3 







1 



0.4 



0601-0700 



7 



2. 



9 



79 



32.6 



1 



0.4 







0701-0800 



9 



3. 



7 



25 



10.3 



1 



0.4 







0801-0900 



5 



2. 



1 



6 



2.5 



1 



0.4 



1 



0.4 



0901-1000 



3 



1. 



2 



6 



2.5 



1 



0.4 







1001-1100 









2 



0.8 



5 



2.1 



1 



0.4 



1101-1200 



1 



0. 



4 



1 



0.4 



6 



2.5 







1201-1300 













6 



2.5 



2 



0.8 



1301-1400 













3 



1.2 



4 



1.7 



1401-1500 













11 



4.5 



7 



3.0 



1501-1600 













15 



6.2 



10 



4.2 



1601-1700 













20 



8.2 



10 



4.2 



1701-1800 













56 



23.1 



9 



3.8 



1801-1900 













78 



36.4 



28 



11.9 



1901-2000 













28 



11.6 



38 



16.1 



2001-2100 



3 



1. 



2 











40 



17.0 



2101-2200 

















29 



12.3 



2201-2300 



2 



0. 



8 











23 



9.8 



2301-2400 

















10 



4.2 



Totals 



243 







242 





242 





236 





7 



