Final answer:
Joe Snyder is proposing a differentiation strategy by introducing a broader range of luxury seafood items to expand and distinguish his restaurant chain's menu.
Step-by-step explanation:
Based on the information provided, Joe is proposing a differentiation strategy. This strategy involves adding a broader range of seafood to appeal to luxury tastes and differentiate the restaurant's offerings from competitors. It's a plan to enhance the uniqueness of their products and attract customers willing to pay more for premium options.