Related Clues:

• Deli sandwich choice
• Lunch fish
• Fish that's high on the food chain
• Melt ingredient, often
• Piscine symbol of overcrowdedness
• With 35 Across, sandwich stuff
• Sushi serving
• Tightly packed pilchard
• Salade niçoise ingredient
• Source of omega-3
• Subway rider during rush hour, metaphorically
• Bluefin, for one
• Sushi-bar selection
• Fish in cans
• Chicken of the Sea, e.g.