454 
PACIFIC SCIENCE, Vol. XXI, October 1967 
TABLE 9 
Seasonal Variation in the Percentages of Mature Individuals Carrying Ova (O) and 
Young (Y), Mean Size (MS) and Size Range (SR), and Average Number per Trawl 
Hour (n/th) for Vibilia viatrix 
SEASON 
O 
Y 
MS(mm) 
SR (mm) 
n/th 
Summer 
12% 
25% 
9 
4-15.5 
38 
Fall 
20% 
40% 
9 
7-12 
8 
Winter 
9% 
60% 
10.5 
7-14 
5 
Spring 
3% 
21% 
11.5 
8.5-15 
3 
spring and summer months, as is shown by a 
drop in mean size and an extension of the 
lower limit of the size range along with an 
increase in the average number per trawl hour. 
All of these indications became obvious during 
the summer. 
Family phronimidae 
Phronima sedentaria (Forskal) 
A total of 575 individuals was sorted from 
pint aliquots. Previously reported reproductive 
data on P. sedentaria were reviewed by K. H. 
Barnard (1932), who indicated that, in the 
more northern regions of its distribution, this 
species has its highest period of reproductive 
activity during the summer and fall months. 
Table 10 gives the breeding information 
gathered in this present study. 
The peak of egg production occurred in the 
summer. Since the developing young of this 
species are carried for some time on the inner 
walls of the salp "barrels” in which P. seden- 
taria is known to live, and only a few of these 
"barrels” were collected, probably the per- 
centages of females with young are inaccurate. 
Because of the confusion regarding the release 
of young from the parents (or from the bar- 
rels), it is difficult to analyze the size variations 
as related to breeding season. In addition to 
this problem, one can see from Table 10 that 
the extensions of the lower limits of the size 
range for males and females do not coincide. 
In spite of these difficulties, however, males 
were most prevalent during the times of high 
egg production and the other data do indicate 
greatest reproductive activity during the sum- 
mer and fall months, concurring with Barnard’s 
1932 report. 
Family paraphronimidae 
Paraphronima gracilus Claus 
A total of 472 specimens was collected from 
pint aliquots. Hurley (1956) reported a single 
female with young in the brood pouches during 
August. His work was conducted in the local 
southern California area near the collection sites 
of this present study. 
As indicated in Table 11, the highest per- 
centages of ovigerous females were noted in the 
fall and females carrying young were most 
TABLE 10 
Seasonal Variation in the Percentages of Mature Females Carrying Ova (O) and Young 
(Y), the Mean Size of Females (MSf) and Males (MSm), Size Range of Females (SRf) and 
Males (SRm), the Female/Male Ratio (f/m), and the Average Number per Trawl 
Hour (n/th) for Phronima sedentaria 
SEASON 
O 
Y 
MSf 
(mm) 
MSm 
(mm) 
SRf 
(mm) 
SRm 
(mm) 
f/m 
n/th 
Summer 
53% 
20% 
25 
16 
11-35 
11-17 
2.4/1 
20 
Fall 
20% 
3% 
22 
14 
14-33 
9-18.5 
2.2/1 
15 
Winter 
7% 
22% 
27 
13 
13-35 
11-15 
10/1 
8 
Spring 
25% 
19% 
28 
none 
18-37 
none 
no males 
3 
