Which measurement scenario is true regarding plate counting in sticklebacks?

• A. Plate number is counted on both sides; total plated sides is twice the plate count per side
• B. Plate number is counted on a single side only
• C. Plate number is counted only on the dorsal edge
• D. Plate number is not measurable

Answer: (C)

When you’re measuring plate counts in sticklebacks, the goal is to get a consistent, comparable tally across different fish. Plates run along the body, but visibility and exact placement can vary with orientation and condition. Counting only on a single, stable region provides a reproducible method. The dorsal edge is that stable region: it’s a visible strip along the back where plates are regularly arranged, and counting there avoids the complications that come with trying to count on both sides or on regions that can be obscured or damaged. By focusing on the dorsal edge, you get a standardized count that’s easy to compare between individuals, making it the best approach for plate counting in this context.