Smoked Whitefish and Fennel Salad

From a list of some long lines people endure in New York City (The New York Times, August 4,1996):

Zabar’s [the legendary New York culinary emporium that began as a humble Jewish appetizing store]: As preparations to break the Yom Kippur fast begin, the line at the lox counter has been known to wend its way out the door onto Broadway, around the block, and along West End Avenue.

Smoked and pickled fish are among the most popular bre