64 
PACIFIC SCIENCE, Vol. XIV, January I960 
DATE 
SEA AREA 
PLANKTON 
POLLACK 
ANGLED 
NO. OF BIRDS 
OBSERVED 
June 17 
Near Agattu 
Very scarce 
( collected ) 
15 
61 
June 18 
Agattu-Kiska 
Strait 
— 
49 
285 
June 22 
60 m. E. of 
Commander Is. 
Abundant 
( collected ) 
Scores 
190 
June 23 
W. of Attu Is. 
Abundant 
( euphausids ) 
— 
659 
(A big flock) 
June 26 
200 m. S. of 
Commander Is. 
Scarce 
( collected ) 
— 
77 
plankton was not made, although in some col- 
lections made for the Fisheries Bureau, Sagitta 
species were very abundant locally, but the fol- 
lowing may show some relationship with bird 
density. 
Pollack were caught for a short time after sun- 
set by 4-5 crew members, and it is indicated in 
the data above that a correlation exists among 
abundance of plankton, pollack, and sea birds. 
In the tropical Pacific, Thompson ( 1951 ) found 
a parallel increase of jellyfish and the black- 
footed albatross toward cooler waters, and from 
his observation he derived a "Jellyfish Index.” 
In the above case, the "Pollack Index,” the num- 
ber angled per unit of time by the same persons, 
might serve as an index of productivity in 
northern seas. 
TEMPERATURE PREFERENCE IN 
SOME SEA BIRDS 
As mentioned above, the sea birds are either 
cold or warm adapted, therefore temperature 
dependent in distribution. This is best shown by 
the Tubinares, as briefly described below (see 
Fig. 4). 
THE albatrosses: Of the two species, Dio- 
medea immutabilis is less warm adapted. It was 
commonest in the convergent sea surface, and 
D. nigripes distinctly preferred the warm cur- 
rent zone. But even the latter species is not a 
tropical bird. Thompson (1951) reports an in- 
crease in number as the water temperature de- 
creased from 27.7° C. to 14.4° C. in the eastern 
Pacific. During its winter breeding season, the 
air and water temperatures around the sub- 
tropical islands, Torishima or Bonin Is., are both 
below 20° C. The temperatures markedly in- 
crease during the summer when D. nigripes 
moves north to cooler waters. This cool adapta- 
tion cpuld explain their winter reproductive 
cycle, which is unusual for the northern hemis- 
phere (Kuroda, MS). From my observation, 
the temperature preference of the two species 
is suggested below. 
D. immutabilis 
D. nigripes 
Air Temperature (°C.) 
Range 
6.2-22.5 
7.0-22.5 
Preferred 
13-15 
17-22.5 
Water Temperature (°C.) 
Range 
5-15.5 
5-16 
Preferred 
7-8 
10-16 
THE storm PETRELS: Both Oceanodroma fur- 
cata and 0 . leucorhoa are cold adapted species, 
although the latter shows wider temperature 
adaptation as it migrates in winter to tropical 
waters. Zoogeographically their main distribu- 
tion ranges were segregated north and south, 
although they overlapped. A distinct concentra- 
tion of O . furcata was found in the north in 
waters east of south Kamchatka (air tempera- 
ture, 7-8° G; water temperature, 5.6-73° G), 
while concentrations of O. leucorhoa occurred 
in the Offshore Kuriles Convergence (air 13- 
15° C., water 6.6-8° C), where furcata de- 
creased. But just north of this concentration, 
O. leucorhoa also showed a clustered distribu- 
tion, both on June 11 and July 6, within the 
cold Kuriles current (air 3.5-4 and 9.2-11° C., 
water 2.3-3 and 5° C.). In this case, too, the 
