462 
Fishery Bulletin 106(4) 
0 Greenland 
halibut 
O Fishing effort 
200 
300 
400 
500 
600 
700 
O O 
O O 
o O 
o o 
o 
O o 
o O 
MAR 04 
° O 
O O 
- 
1 o • 
.0 
o 
• O o 
’o 
Cl 
O o 
O 
0 
o 
o 
NOV 03 
4/ 
500 
600 
700 
500 
600 
0 
100 
200 
300 
400 
500 
600 
700 
O 
O 
O 
O 
• 
o 
o 
o 
o 
o 
o 
o 
O 
o 
o 
o 
o 
O 
o 
o 
o 
O 
o 
O 
\o • 
o* 
AUG 04 
• 
P 
sO 
100 
200 
300 
400 
500 
600 
700 
700 
o 
O 
o 
o 
o 
o 
o 
O 
O 
o 
o* 
o- 
o 
o 
° 
o 
o 
o 
o 
o 
a 
o 
\0 
6 
© 
NOV 04 
0 
100 
200 
300 
400 
500 
600 
700 
O 1 o 
O 
o 
o 
° O 
o 
O 
o 
° O 
o 
O 
o 
° o 
o 
O 
o 
• *o 
o 
JD 
o 
O 
*> 
MAR 05 
q 
0 
100 
200 
300 
o O' o o'O 
o o O O o 
o o O o O 
lP-O OO 0 
400 ^ 
Q.; 
400 500 600 700 
Bottom depth (m) 
500 
600 
700 
800 
900 
1000 
1100 
1200 
o'O o'O 
o o o o 
o o o o 
O-Q o Q 
o23 ° 
■' Q*. 
AUG 05 
500 600 700 800 900 1000 
Bottom depth (m) 
1100 
O 
O 
o 
o 
o 
o 
o 
Q 
O 
o 
o 
o 
1200 
1300 
Figure 4 
Pelagic catches (noted as individuals) of Greenland halibut (ReinharcLtius hippoglossoides) 
on vertical longlines. Individual catches are shown by bottom depth (m) and catch depth (m). 
Fishing effort is shown for each 100-m catch depth interval and 50-m bottom depth interval. 
The area of the fishing effort symbol is proportional to fishing effort (hooks x hours/100). 
The straight diagonal line represents the bottom. 
P<0.01). In November all Greenland halibut caught 
were classified as late maturing or ripe, whereas in 
catches from March and August all but three individu- 
als were immature or early maturing. 
Individual depth trajectories 
Of the 25 recaptured fish with intact archival tags, the 
time recorded varied from a few weeks up to two years, 
yielding a total of 296,000 depth recordings. All tags 
were both released and recaptured at or close to the 
continental slope (Fig. 1). For all recordings combined, 
the 25th, 50th, and 75th percentiles of depth were 454, 
522, and 617 m, respectively. Six percent of all record- 
ings were from depths above 300 m, from 11 recaptures. 
For individual tags this percentage ranged from zero to 
20%, with a mean of 2.8%. One individual was regularly 
recorded above 100 m depth, and seven individuals were 
recorded below 1000 m. Only one of the 16 individuals, 
for which sex was determined, was male. 
Most of the recaptured tags revealed alternating pe- 
riods of distinctly different vertical activity by Green- 
land halibut. Such periods were apparent on both 
small (hours-days) and large (days-months) scales. 
Diurnal variation was most apparent at depths above 
300 m (Fig. 7). Here the occurrence of large stan- 
dardized vertical distance (VD) between successive 
records was three times higher at night (21h-03h) 
than during the midday (09h-15h), and records of 
vertical inactivity (VD< 0.5 m per hour) were twice as 
numerous during daytime (Fig. 7). Above 300 m, the 
total number of observations was 19% higher at night 
