This is a Japanese food item called sushi.  California roll is seen here, it is a kind of sushi called "maki," or rolled sushi.  The remaining pieces are called "nigiri" sushi.  Octopus, red clam, salmon roe, shrimp and what appears to be a big slice of yellowtail are evident.  Also on the tray are a small green ball of horseradish and neatly folded slices of pickled ginger.