Opistb oteuthis calif orniana — PEREYRA 
431 
Fig. 1. Temporal and bathymetric distribution of male and female Opisthoteuthis calif orniana based on 
capture of 28 individuals on a trackline off the mouth of the Columbia River, July 1961-May 1963. 
suggest that Berry (1949:26 and 1952:183) 
was correct in surmising that these animals are 
probably not unduly rare where suitable bot- 
tom conditions exist. The average catch rate 
over the depth range where they were taken 
on the Columbia River trackline was approxi- 
mately 0.4 individuals per hour of trawling 
(Table 2). Within the range of depth where 
the species were found, they were most fre- 
quently encountered from 375 to 450 fathoms 
(686-823 m). Due to the low effort from 475 
to 575 fathoms (868-1051 m), where only 
two drags have been made, its relative abun- 
dance in deeper water is not well known. 
The bimodal nature of the catch-per-unit-of- 
effort curve may result from several factors. As 
shown earlier, the sexes are distributed un- 
evenly, with the males found in shallower water 
than the females. This could create the appar- 
ent non-normal distribution. Another factor 
which may be responsible is the direct or in- 
direct effect of bottom type on distribution. 
Green mud was found to predominate over 
the range where the species was encountered; 
but inside of 325 fathoms (594 m) and at 400 
fathoms (731 m), where the catch per effort 
was low, the sand/mud ratio was higher 
( > .08 ) than was found at adjacent stations 
