An aquaculture facility hatched salmon eggs and released young fish into a river leading to the ocean. The fish fed and grew in the ocean, and in a few years they returned to the facility. Because the number of returning fish was low, a scientist suggested adding a chemical to the river that would __________.

• A. allow them to form a cognitive map
• B. increase their capacity for spatial learning
• C. provide an opportunity for associative learning
• D. enhance social learning
• E. enable them to imprint on the facility

Answer: (E)

Verified step by step guidance

1. Step 1: Understand the concept of imprinting in animals. Imprinting is a form of learning where an animal, during a critical period early in life, forms attachments and develops preferences that influence behavior later on.
2. Step 2: Recognize the importance of imprinting for salmon. Salmon imprint on the chemical signature of their birthplace, which helps them navigate back to the same location to spawn.
3. Step 3: Consider the problem of low numbers of returning fish. This suggests that the fish may not be successfully imprinting on the facility, which is crucial for their return.
4. Step 4: Evaluate the options provided. The options include cognitive map formation, spatial learning, associative learning, and social learning. None of these directly address the need for imprinting.
5. Step 5: Conclude that the correct solution involves enabling the fish to imprint on the facility. This would involve adding a chemical to the river that mimics the unique chemical signature of the facility, aiding the fish in recognizing and returning to it.