Opisthoteuthis calif orniana — PEREYRA 
435 
TABLE 3 
Fecundity Observations on Three Mature Female Opisthoteuthis califomiana 
Taken on the Columbia River Trackline 
DATE 
DEPTH 
(fathoms) 
SIZE 
(mm) 
TOTAL 
VOLUME 
EGGS (ml) 
NO. EGGS 
^3 mm 
(length) 
NO. EGGS 
<3 mm 
(length) 
% 
LARGE 
EGGS 
LARGEST 
EGG (mm) 
LENGTH X 
WIDTH 
3-7-62 
425 
210 X 150 
5.0 
98 
150-200 
33-39 
10 X 5 
7-3-61 
425 
255 X 250 
3.3 
125 
150-200 | 
46-56 
9X5 
12-11-61 
375 
340 X 330 
23.0 
324 
125-150 
68-72 
11 X 6 
egg reported by Berry (1952:185) (9 by 5 mm). 
The percentage of large eggs (greater than 
or less than 3 mm in length was arbitrarily 
chosen to designate large and small eggs, re- 
spectively) differed for each individual, with a 
range from 33 to 72%. Likewise, the volume 
of eggs in the ovary ranged from 3.3 ml to 23.0 
ml. In the specimen with 72% large eggs (egg 
volume of 23.0 ml), the majority of the large 
eggs were located in the upper part of the 
ovary with ripe eggs spirally arranged in a 
Compact group just under the oviducal gland 
(Fig. 4). In no case was there any indication 
of stalk development. 
The extent of egg development was used as 
circumstantial evidence indicating the season of 
ovulation. The highest degree of egg develop- 
ment was observed in a female containing ripe 
eggs, captured on the 11th of December. The 
least development was found for the March 
capture, while the female captured in July 
showed an intermediate degree of development. 
With only three samples represented no un- 
equivocal conclusions are permitted, but indica- 
tions are that ovulation occurs during the 
winter. 
Food 
The stomachs of eight specimens were ex- 
amined to ascertain the food organisms (Table 
4). Only one stomach was found completely 
empty and the remaining stomachs contained 
very little, never more than 5 ml. The material 
in greatest abundance* was crustacean remains, 
mostly small mysids (approximately 7 mm in 
length) and large copepods. Only one non- 
crustacean organism was found, a polychaete; 
and this was partially digested and positive 
identification was not possible. A few amphi- 
pods, isopods, and a masticated shrimp, prob- 
ably a hippolytid or crangonid species, were 
also recognized. No quantities of mud were 
mixed in with the stomach contents, but a few 
sand grains were found in the stomach of the 
Unimak Island specimen. In some stomachs a 
brown organic material was found mixed with 
the food, but the exact composition of this 
material is not known. Fecal remains left in 
the aquarium by the live individual appeared 
to contain this same material. 
The above summary of gut-contents par- 
tially substantiates the speculation by Berry 
(1952:187) that this species feeds mainly on 
micro-plankton or detritus swept down the disc 
by the radial series of cirri toward the mouth. 
The detrital element of its diet has not been 
substantiated, but the presence of the small 
crustaceans in the gut verified the planktonic 
feeding habit. The size of the plankton indi- 
cates that the animal is more of a macro- than 
a micro-plankton feeder. 
A few mysids found in the esophagus of one 
individual were entire, as were most of those 
found in the first stomach of the others. Only 
one organism was noticeably bitten, the small 
hippolytid or crangonid shrimp. Thus it ap- 
pears that except for a few of the larger or- 
ganisms the majority were taken entire and 
not first reduced by the strong beak. As Rob- 
son (1925:1348-1349) has suggested, the food 
is probably ground down in the muscular first 
stomach and digested in the second, instead of 
being partially comminuted by the radula with 
preliminary digestion in the crop, as occurs in 
species that possess the latter two structures. 
