256 
Fishery Bulletin 95(2), I 997 
® 
- 5 larvae 
© 
- 175 larvae 
Figure 6 
NOAAship Oregon II cruise 166, leg 1, 25 April-16 May 1987. Symbols as 
in Figure 2. Number of larvae under 10 m 2 ranged from 7 to 50 individuals 
per station. 
tween larval C. pauciradiatus and the close proxim- 
ity of a temperature front across all cruises yielded 
a value of 34.128 with a P-value of <0.01, indicating 
a very strong correlation between the 
presence of C. pauciradiatus and fron- 
tal zones. Of stations with C. pauci- 
radiatus, 84.7% occurred at <5 km, and 
15.3% were >5 km from a front. For all 
stations, the values were 51.8% and 
48.2%, respectively. 
Such tight spatial correlations with 
frontal zones are best seen by compar- 
ing the abundance of C. pauciradiatus 
in the transects with that in the surveys. 
In both legs of the 1987 survey a com- 
bined mean of 207 (under 10 m 2 ) larval 
C. pauciradiatus were caught at 14 grid 
stations. Mean abundance averaged 2— 
3 fold higher in frontal zones, for 70% 
of these larvae ( 160) were taken at nine 
stations that were on or near a front. 
Only five stations with 47 larvae (30%) 
were not associated with an identifiable 
frontal structure. 
In the same 1987 survey, 6 dedicated 
transects across the Loop Current 
caught a combined mean of 693 larvae 
(number under 10 m 2 ). Larval C. pauci- 
radiatus were caught at 22 bongo sta- 
tions and another 91 were taken in 
neuston tows. If these numbers are com- 
bined, 94.5% were caught along frontal 
zones. 
Results were similar in 1988. During 
the grid survey, 13 stations contained 
343 C. pa uciradiatus, only one of which 
was not associated with the front. This 
station accounted for only 1.7% of the 
larvae. In the one transect, 330 C. 
pauciradiatus larvae (under 10 m 2 ) were 
found at 9 of 16 stations. 
Further examination of these tran- 
sects across the Loop Current and the 
grid stations shows that C. pauci- 
radiatus occur primarily on the cold side 
of the temperature gradient. When the 
temperature gradient is well defined 
and C. pauciradiatus are present across 
the front, abundance is highly corre- 
lated with bulk plankton standing 
stocks (displacement volume maxima). 
The pattern can be clearly seen in 
transect III and in the transect com- 
pleted in 1988 (Figs. 15 and 16). In 
transect III, C. pauciradiatus were not 
present until sea surface temperature (SST) started 
to increase, and their abundance peaked just before 
an SST maximum. Bulk plankton displacement vol- 
