Pelagic Cephalopods — PEARCY 
265 
Fig. 3. Size-frequency distribution of Gonatus fabricii and Gonatus larvae found in midwater trawl samples 
during the summer (July-September) and other seasons of the year (October-June). 
squid in either case, size-frequency distribu- 
tions were examined. 
During the summer the catch of Abraliopsis 
sp. consisted mainly of small individuals (less 
than 30 mm DML), whereas during other sea- 
sons larger squid predominated (Fig. 2). On 
the other hand, the size distribution of Gonatus 
larvae and G. fabricii (assuming they are in 
fact one species) are similar for both summer 
and non-summer periods (Fig. 3). This sug- 
gests that breeding of Abraliopsis is largely 
seasonal, while that of Gonatus is not. 
Seasonal differences between the size struc- 
tures of each species may result from growth, 
mortality, and movements of the populations. 
Growth, and attendant mortality, may explain 
differences between the size modes and rela- 
tive abundance of Abraliopsis during the two 
periods. But other factors appear to be in- 
volved with Gonatus. Gonatus specimens over 
30 mm in length constituted a larger propor- 
tion of the total catch during the summer than 
in other seasons (21% versus 7%). In addi- 
tion, the catch of large Gonatus per tow during 
the summer was greater than that of small 
Gonatus (30 mm) during the other seasons. 
These differences suggest an influx or migra- 
tion of these squid into slope waters during 
the summer. Perhaps this is caused by oriented 
swimming of squids or by a concentrating ef- 
fect of ocean circulation. 
