448 
Fishery Bulletin 109(4) 
Table 1 
Results of forward selection multiple regression models relating the average weight (kg) of American shad (Alosa sapidissima ) in 
Alaska Fisheries Science Center (AFSC) and Northwest Fisheries Science Center (NWFSC) sampling surveys in different years 
to sea-surface temperature (SST), bottom depth, and day of year. Shown for each model are the significant (P<0.05) coefficients 
and r 2 (coefficient of determination). SST was not available from the NWFSC sampling. 
Year 
No of hauls 
SST 
(kg/°C) 
Regression coefficients for weight 
Depth 
(kg/m) 
on: 
Day of year 
(kg/d) 
r 2 
AFSC 
1977-2004 
1168 
ns 
0.0029 
0.0027 
0.23 
1977 
29 
0.12 
ns 
ns 
0.15 
1980 
26 
ns 
0.0120 
ns 
0.46 
1983 
133 
ns 
0.0024 
0.0039 
0.20 
1986 
152 
ns 
0.0044 
ns 
0.18 
1989 
94 
0.04 
0.0040 
ns 
0.38 
1992 
191 
ns 
0.0021 
0.0057 
0.36 
1995 
154 
ns 
0.0018 
0.0056 
0.35 
1998 
163 
a 
0.0026 
0.0050 
0.43 
2001 
95 
ns 
0.0029 
0.0025 
0.25 
2004 
108 
ns 
0.0031 
0.0025 
0.23 
NWFSC 
2003-08 
387 
— 
0.0026 
ns 
0.15 
2003 
57 
— 
0.0038 
ns 
0.28 
2004 
76 
— 
0.0041 
0.0020 
0.36 
2005 
106 
— 
0.0025 
ns 
0.16 
2006 
60 
— 
0.0017 
ns 
0.08 
2007 
52 
— 
0.0030 
ns 
0.14 
2008 
36 
— 
ns 
ns 
0.00 
a SST was removed from model because it was highly correlated ( R>0.5 ) with the other, stronger variables. 
Table 2 
Total landings of American shad ( Alosa sapidissima) in known management areas for British Columbia (1997-2010 provided 
by Department of Fisheries and Oceans), and Oregon, Washington and California (1981-2010 provided by the Pacific Fisheries 
Information Network database). Data for the United States are summarized for ocean, inland, and unknown areas and for the 
two seasons: April-October (summer) and November-March (winter). 
Area 
Ocean/ 
Inland 
Season 
Weight 
landed (t) 
Area 
Ocean/ 
Inland 
Season 
Weight 
landed (t) 
BC 
Ocean 
Summer 
17 
CA 
Ocean 
Summer 
13 
Ocean 
Winter 
3 
Inland 
Summer 
23 
OR and WA 
Ocean 
Summer 
420 
Ocean 
Winter 
27 
Inland 
Summer 
2307 
Inland 
Winter 
51 
Unknown 
Summer 
577 
Unknown 
Winter 
3 
sampling survey. However, shad landed off Vancouver 
Island were usually larger (2. 0-3.0 kg; Davidson and 
Fargo 5 ) than farther to the south (Figs. 6 and 7), in- 
dicating that larger shad may migrate farther to the 
north and remain in these cooler water longer, as do 
other pelagic species, such as Pacific whiting (Bailey 
et ah, 1982; Dorn, 1995) and sardine (Emmett et ah, 
2005). Increased tolerances of cool water by large shad 
may explain both their extensive inshore-offshore and 
latitudinal distributions. 
We found that shad occurred over a wide range of 
sea-surface temperatures; largest catches occurred 
