BATHYPELAGIC SQUID BATHYTEUTHIS 169 



restricted zone between 2250 and 2500 m the average was 2.79 speci- 

 mens per 2-lionr tow. Therefore tliis zone may account for 1.29 speci- 

 mens per tow. 



These different approaches to the determination of the deeper levels 

 of distribution lead to the conclusion that B. ahi/ss/'cola does not occur 

 in appreciable numbers below 2500 m and that the lower range of 

 occurrence for this species is in the region of 2250-2500 m. A closer 

 estimation than this is not warranted because of the nature of the sam- 

 pling gear and the variability involved in determining depth of cap- 

 ture primarily from wnre angle. 



A further test of the method is to examine the individual tows taken 

 below 2500 m where an apparently large number was captured. For 

 each tow the number of specimens is calculated that would be expected 

 during the time it took to pass through the productive layer. 



Four tows that fished below 2500 m caught an apparently large 

 number of specimens : 



Eltauin 

 station 

 number 



Actual Nu))i'bcr Average No. Number 



number hours in specimens expected in 



specimens productix^c expected productive 



captured zone per 2 hrs. zone 



1323 4 2. 3 2. 63 3. 1 



1288 4 3. 3 2. 63 4. 3 



867 7 3. 5 2. 63 4. 6 



782 6 .5. 2. 63 7. 2 



The two tows that caught more specimens than would be expected 

 should be comi)ared with other IKMT tows taken in the same area at 

 the same time. In the immediate vicinity of station 1323 four IKMT 

 tows to the productive zone produced 6, 9, 11, and 15 specimens, all 

 well above the average. This is an area of high concentration of B. 

 ah7/ssico?a. and it indicates that the estimated catch here is too low 

 and that most (or all) of the four specimens from 1323 were taken 

 above 2500 m. 



With station 867 the picture is not quite so clear because other tows 

 taken within the immediate area were all made at less than 1300 m 

 where relatively few specimens w-ould be expected. Station 858, taken 

 at the same longitude and 2° farther south, was the closest tow that 

 fished at a depth where B. ahysf^icola is abundant, and it caught twelve 

 specimens, considerably more than the average. Therefore, it is prob- 

 able in this case, too, that apparently high numbers taken beloAV 2500 m 

 were actually taken in the shallower zone of abundance. 



Figure G2 gives the total number of specimens captured by standard 

 2-hour tows with depth. The bulk of the population occurs between 

 1000-2500 m. (A slight decline in numbers occurs between 1500- 



