Measure the work before interpreting the outcome.
Primary delivery proof is survey effort: route geometry, hours and distance. Sightings provide biological observations; they are not a success metric by themselves.
Four objects. No fake certainty.
Corridor
The ferry route surveyed between England and Spain.
Effort
Hours and distance actually surveyed on that route.
Observation
Recorded sightings attached to survey effort.
Context
Shipping, noise, fishing, climate and habitat layers may sit beside observations without implying unsupported causality.