LeClair et al.: Seasonal changes in abundance and migration of Sebastes auhculatus and 5. cauhnus 
305 
The reef was constructed in 1983 by the Washington 
Department of Fisheries (now the Washington Depart- 
ment of Fish and Wildlife) for the purpose of increasing 
the number of productive recreational fishing sites in 
the region (Buckley 1982). It covers an area of approxi- 
mately 5400 m^ and is constructed of various-size quar- 
ried boulders and cobble interspersed with long hori- 
zontally placed concrete beams. The near- and offshore 
margins of the reef lie at a depth of about 4 and 36 m, 
respectively. The surrounding seafloor consists primar- 
ily of unconsolidated sand, shell hash, and gravel, as 
well as widely dispersed small glacially deposited boul- 
ders. The reef is situated on a steeply sloping bottom 
that descends to depths of nearly 240 m over a distance 
of about 3 km to the approximate center of the passage 
that separates Vashon Island from the mainland (East 
Passage, Fig. 1). Large year-round patches of eelgrass 
{Zostera spp.) occur in the shallow water shoreward of 
the reef and dense growths of perennial nonfloating 
macroalgae (e.g., laminarians, ulvas, palmarials) form 
over the shallower portions of the reef during the sum- 
mer and fall. Bull kelp {Nereocystis leutkeana), the pre- 
dominant canopy-forming floating kelp in Puget Sound, 
does not grow on or near the reef. Twenty-two years 
had elapsed between the construction of the reef and 
the commencement of our study and we presume that 
sufficient time had passed for ecological succession to 
have occurred. 
In 2005, 3 permanent straight-line 60-m transects 
(T-1, T-2, and T-3), each running due east-west (as per 
standard compass) and separated by a distance of at 
least 10 m, were established on the reef. The tran- 
sects ran perpendicular to shore and were strategi- 
cally placed in order to capture the dominant micro- 
and macrohabitat features of the reef (e.g., boulder, 
cobble, beams, sandy bottom, high and low relief, reef 
margins, crevice and overhang space). The nearshore 
ends were positioned in 4.5, 4.0, and 6.0 m and the 
offshore ends in 21.5, 21.0, and 20.5 m for T-1, T-2, and 
T-3, respectively. The offshore ends of each transect 
were semipermanently marked with a buoyed line of 
about 1 m in length fastened to a hollow-core cinder 
block of approximately 40x20x20 cm affixed to the 
seafloor with 2 steel bars. Coordinates (based on the 
North American Datum of 1983) for the offshore mark- 
ers were as follows: T-1, 47.420040°N, 122.427145°W; 
T-2, 47.420082‘>N, 122.427182'>W; T-3, 47.420579°N, 
122.426947°W. Real-time coordinate-corrected positions 
were obtained by connecting a line between the tran- 
sect marker to a surface buoy and registering the posi- 
tion with a GeoExplorer 6000 Centimeter Edition® GPS 
receiver (Trimble Navigation Ltd., Sunnyvale, CA). 
The transects were divided into twelve, 5-m seg- 
ments each and were surveyed by scuba divers swim- 
ming in tandem along the bottom from deep to shallow 
9 Mention of trade names or commercial companies is for iden- 
tification purposes only and does not imply endorsement by 
the Washington Department of Fish and Wildlife or the Na- 
tional Marine Fisheries Service, NOAA. 
and pausing briefly at each segment marker. During 
surveys, divers counted fish in each segment on their 
respective sides of the transect centerline to a width 
of 2 m (total bottom coverage per transect=240 m^) 
and as high into the water column as visibility per- 
mitted. Hand-held lights were used to search beneath 
overhangs, in crevices, and in other poorly lit areas. In 
order to ensure consistent effort among surveys, the 
slowest practical swimming speed was maintained over 
each transect as governed by the maximum allowable 
safe bottom-time using conventional scuba. 
All species of fish that were conspicuous to the div- 
ers were recorded and enumerated. Highly cryptic spe- 
cies or species that remain very small into adulthood, 
though occasionally noted, were not targeted in the 
search effort. Careful written and hand-signal com- 
munication between divers reduced the risk of count- 
ing fish twice when they were swimming across tran- 
sect from one survey lane to the other. Individual fish 
from the 3 most visually dominant taxonomic families 
(Sebastidae, Embitocidae, and Hexagrammidae) were 
recorded to species and their length (all fish lengths 
herein are reported as total length [TL] in centimeters) 
was estimated into length classes, which varied among 
species. The occurrence of apparent late-stage gravid 
brown and copper rockfish, evidenced by their promi- 
nently distended abdomens, was also noted. Cooper 
(2003) showed that bulging abdomens can be a reliable 
means for identifying late-stage gravid copper rockfish 
when they are viewed underwater. 
In 2005, surveys were conducted on all 3 transects 
during the summer, but only on T-2 in the fall, and no 
surveys were conducted during the spring of 2005 or 
the winter of 2005-2006. Beginning in the spring of 
2006, each transect was surveyed at least once dur- 
ing each season through summer of 2012. In most in- 
stances, multiple transects were not surveyed on the 
same day. The order in which transects were surveyed 
during any given season was randomly determined. 
No attempt was made to synchronize the surveys to 
the cycle of the tides; therefore the surveys occurred 
over a broad range of tidal conditions. Strong tidal cur- 
rents are not generally encountered over the reef and 
current velocities rarely exceed 1.5 knots. The mean 
range of the tide at PHAR is approximately 2.4 m. 
Temperature data loggers (HOBO® Pro v2, Onset Com- 
puter Corporation, Bourne, MA) were deployed at the 
near- and offshore margins of the reef (4.5 m and 28 
m, respectively) and they recorded water temperature 
every 4 hours for a period of one year beginning 8 De- 
cember 2006. 
In order to mitigate the potential effects of observer 
variation, only 5 divers were used throughout the en- 
tire course of the study and all surveys on the south 
side of the transect center-lines were conducted by the 
same diver. Four different divers conducted surveys on 
the north side of the transect center-lines; but nearly 
all (-96%) of those surveys were conducted by just 2 
divers. All scuba divers had extensive experience in 
surveying rockfish on Puget Sound rocky reefs prior to 
