478 
Fishery Bulletin 96(3), 1998 
Table 9 
Von Bertalanffy growth parameters and lengths at maturity for Alaska (AK) and west coast sablefish. Growth parameters are 
based on age data (Kimura et al., 1993). Lengths at maturity for Alaska are from Sasaki (1985), and for the west coast are from 
Parks and Shaw (1983). 
Region 
Location 
Sex 
L_ (cm) 
K 
t 0 (yr) 
Length at 
maturity (cm) 
Alaska 
male 
70.2 
0.120 
-8.06 
female 
86.7 
0.106 
-6.15 
Bering Sea 
male 
65 
female 
67 
Aleutian Islands 
male 
61 
female 
65 
Gulf of AK 
male 
57 
female 
65 
West coast 
male 
54.7 
0.472 
-1.82 
female 
61.0 
0.499 
-0.81 
Bodega Canyon 
male 
52.7 
female 
55.3 
Patton Escarpment 
male 
54.8 
female 
56.3 
Depth-related tagging data for sablefish are very 
difficult to interpret for several reasons. First of all, 
surveys, and therefore tag releases, did not cover the 
full bathymetric distribution of sablefish. Second, 
commercial fishing, and therefore recovery effort, did 
not cover the full bathymetric distribution of sable- 
fish. And finally, the bathymetric distribution of a 
species abundant across such a broad latitudinal 
range as sablefish, might be expected to vary by lati- 
tude. 7 Most of our evidence supports the hypothesis 
that sablefish seem to have a deeper, lower limit to 
their distribution off the west coast, compared with 
their distribution off Alaska. 
The principal depth-related result for Alaska sable- 
fish is that the depth distribution of recoveries is simi- 
lar regardless of the depth of tagging (Table 7). Al- 
though the depth distribution of recoveries naturally 
follows recovery effort, it also suggests a certain 
amount of random movement in relation to depth 
over time. The depth-related data for west coast 
sablefish are even more difficult to decipher. These 
data show an extremely low recovery rate from fairly 
heavy tagging of fish from the 400-1000 m depth 
zone. The reason for this low recovery rate is un- 
known. Perhaps, the strongest conclusion to emerge 
7 One reviewer noted the term “latitudinal emergence,” where 
deeper dwelling species are thought to have shallower upper 
limits on their bathymetric distributions in the more northern 
limits of their range. However, we did not find this term to be 
widely used in the literature. 
from our study is that we still have more to learn 
about sablefish depth distributions. 
Effects of ENSO on migration and growth 
It seems natural that the growth of pelagic species 
off the west coast, such as Pacific whiting ( Merluc - 
cius productus) and Pacific salmon ( Onchorynchus 
spp. ), would be adversely affected by ENSO events 
(Beamish and Bouillon, 1993; MacLellan and 
Saunders, 1995). It is perhaps more interesting that 
along the west coast, the growth and somatic condi- 
tion of adult rockflsh have been negatively affected 
by ENSO (Lenarz et al., 1995). That the observed 
growth of a deepwater species, such as sablefish, can 
be negatively affected suggests that the feeding of 
many demersal species along the west coast may 
suffer some ill effects from ENSO. In the Gulf of 
Alaska, ENSO growth effects are thought to be op- 
posite of those experienced off the west coast. Growth 
of salmon and groundfish species are thought to be 
significantly enhanced by ENSO events (Beamish 
and Bouillon, 1993; Bakun, 1996). Thus our findings 
that ENSO events retard growth of sablefish off the 
west coast but enhance growth of sablefish off Alaska 
are consistent with this literature. However, this may 
be the first documentation of this effect for a demer- 
sal species. 
The question arises as to why there is a positive 
correlation between Bakun’s upwelling index and 
west coast tag recoveries of Alaska fish (Fig. 8). Are 
