Pearcy and Fisher: Ocean distribution of Alosa sapidissima along the Pacific coast of North America. 
447 
fishery (Majewski and Bellman 8 ; Olson 9 ) indicated that 
the percentage of tows with shad was higher in the 
“summer” (April-October) than in the “winter” (No- 
vember-March). Although the average number of shad 
caught in positive tows was higher in California in the 
winter, catches were still taken in Oregon and Wash- 
ington waters in the winter (Table 3). Lower catches 
per positive tows in the winter may be related to the 
deeper distribution of shad below 200 m in the winter, 
as found by Talbot and Sykes (1958). 
Moreover, shad were rarely caught in fisheries tar- 
geting Pacific sardine ( Sardinops sagax) and northern 
anchovy ( Engraulis mordax ) in southern California dur- 
ing any season of the year (Sweetman 10 ), or in pelagic 
trawling off the central California coast (Brodeur et al., 
2003). During eleven years of sampling (1995-2005) 
with variable mesh gill nets in bays and estuaries of 
California, Allen et al. (2006) and L. Allen * 11 found 
shad in the Klamath and Eel rivers, but mainly in 
San Francisco Bay. These are apparently the only bays 
where shad spawn. In the southern California Bight, 
only 78 American shad were caught in thirteen years of 
sampling in shallow, protected embayments from Santa 
Barbara to Oceanside during the summer and fall. In 
summary, from all these observations of the geographic 
distribution of catches of shad, we see little evidence 
for long-distance seasonal migrations of stocks along 
the Pacific coast and a massive exodus from north- 
ern waters in the fall and large increases in southern 
California waters below 35°N. These differences are 
probably driven by the more extreme ranges of sea- 
sonal temperatures along the east coast in contrast to 
the temperature ranges along the west coast of North 
America. 
In our study, most shad were also caught in bottom 
trawls in shallow water (<150 m depth), which is con- 
sistent with ocean catches in the Atlantic (Neves and 
Depres, 1979), and with the few catches of shad beyond 
the continental shelf in bottom and midwater trawls 
off California, Oregon and Washington (Brodeur et al., 
2003, 2005; Ralston and MacFarlane 12 ). We found no 
evidence that shad were more abundant offshore or that 
they avoided cooler nearshore waters along the Pacific 
coast during the upwelling season by migrating offshore 
as postulated by Leggettt and Whitney (1972). 
Shad caught along the Pacific coast were generally 
larger in deep water along the outer continental shelf 
where bottom temperatures are cooler and surface 
temperatures are warmer during spring and summer 
months than inshore (Table 1). The lower catch num- 
ber for shad off California (Fig. 2A) may also reflect 
10 Sweetman, D. 2010. Personal commun. California Dept, 
of Fish and Game, 8604 La Jolla Shores Dr., La Jolla, CA 
92037. 
11 Allen, L. 2010. Personal commun. Southern California 
Marine Institute, 820 S. Seaside Ave, Terminal Island, CA 
91330. 
12 Ralston, S., and B. MacFarlane. 2010. Personal commun. 
NOAA Southwest Fisheries Science Center, 110 Shaffer 
Rd., Santa Cruz, CA 95060. 
their preference for cool bottom temperatures to the 
north. Although shad weight increased with latitude 
in the AFSC survey (Fig. 6A), it did not in the NWSC 
