Vollen and Albert: Pelagic behavior of adult Remhardtius hippoglossoides 
465 
Figure 8 
Examples of individual depth trajectories determined from archival tags on 
recaptured Greenland halibut ( Reinhardtius hippoglossoides). Examples A1-A3 
from release in November 2002, example B1 from release in August 2003, and 
example Cl from release in August 2005. For A3 the recordings stopped before 
recapture, probably because the fish descended beyond the depth limit that the 
tag was designed to withstand. 
Of all Greenland halibut caught on vertical long- 
lines in August 2005, only 27 individuals, or 14%, had 
recently been feeding, as evidenced by the presence 
of prey in the stomachs. This percentage ranged from 
14% to 40% for fish caught in bottom trawls (Table 
2). Stomachs from specimens caught on vertical long- 
lines contained food from all major prey groups that 
were also found in stomachs of trawl-caught fish. Of 
these specimens, 33% contained fresh prey, i.e. prey 
without signs of digestion. For trawl-caught fish dur- 
ing the same period this percentage was significantly 
lower; only 7% contained fresh prey (% 2 , df=l, P<0.01). 
In terms of percentage by number, 17% of the prey 
items from vertical longlines and 5% from bottom trawl 
catches were classified as fresh (x 2 , df=l, P <0.01). 
The fresh prey of Greenland halibut caught by vertical 
longlines were G. fabricii and the hyperiid amphipod 
Parathemisto abyssorum. The Greenland halibut were 
all captured in waters above an 800-900 m bottom 
depth, and 70% of them were caught more than 300 
m above the bottom. The fresh contents from trawl 
catches consisted of hyperiid amphipods, G. fabricii, 
and Pasiphaea sp., as well as one case of offal. These 
individuals were caught at 600—1200 m depth. 
Pelagic distribution of potential prey 
The acoustic profiles from the extended study area in 
August 2003—05 were all quite similar, with an acous- 
tic layer in the upper 50 m and another around 300 m 
depth (Fig. 11). Data from 2005 showed that this pattern 
continued out to the deeper part of the slope. That year 
the echo sounder was regrettably set to record only down 
to 500 m depths, but data from 2003 and 2004 strongly 
indicated that very little backscatter should be expected 
below 500-600 m. 
