244 
Fishery Bulletin 115(2) 
Location of all initial captures of sablefish {Anoplopoma fimbria) off Newport, Oregon, (blue crosses, inset 
map) and recapture locations of dispersers (fish that moved at least 200 km from their initial capture loca¬ 
tion) for the period 1996-2016. Recaptures are clustered into 0.5° grids to mask exact capture locations. 
Recapture locations of fish categorized as residents, fish that moved <200 km from their tagging location, 
are not shown. Fish from both tagging sets are combined. 
ture rates in depths >900 m for fish initially captured 
in zones 1 and 2 also increased in conjunction with 
the increased fishing effort starting in 2009, providing 
evidence of some movement to deep slope habitats. Ap¬ 
proximately 13% of all fish initially captured in depth 
zones 1 and 2 and recaptured after 2008 were caught 
at depths >900 m. 
Over a time frame of 1-2 decades, our results sug¬ 
gest settlement of sablefish to shelf habitats, then sub¬ 
sequent movement to a broad range of different depths 
along the slope. For females caught in trawl surveys 
of the southern stock, mean age increased with depth, 
but the spread of ages also increased, with fish at the 
deepest depths sampled ranging from 6 to 59 years old 
(Head et ah, 2014, fig. 2), suggesting a pattern of early 
movement to a broad range of depths. The absence of 
older females at shallower depths noted by Head et al. 
(2014) could arise from several processes. Fish could be 
moving progressively deeper with time but at very slow 
rates, as suggested for Dover sole (Microstomus pacifi- 
cus) by Hunter et al. (1990). Fish could also be acceler¬ 
ating their depth-related movement as they age, result¬ 
ing in an accumulation of older fish in deeper habitats. 
Alternatively, higher mortality rates in shallow than in 
deep habitats, either natural or fishing induced, could 
reduce the life span of fish residing in upper slope ar¬ 
eas. A depth-related decline in natural mortality rates 
would be consistent with the hypothesized longevity 
benefits of residence in or near the OMZ, whereas a 
depth-related decline in fishing mortality would be con¬ 
sistent with observed differences in effort by depth, po¬ 
tentially resulting in fishing-induced age truncation in 
the more heavily exploited shallower habitats. 
Seasonal differences in recapture depths for fish 
from zones 1 and 2 indicated occurrence of sablefish 
in deeper waters during the potential spawning sea¬ 
son (November-April) than during the nonspawning 
months of May-October. These depth differences were 
relatively minor; for all recaptures from zones 1 and 2 
combined, mean depths were 122 m deeper in spawning 
than in nonspawning months. However, they do sug¬ 
gest movement to deeper waters as spawning begins. 
