That's because, unlike mangroves and warm-water coral reefs, seagrass meadows aren't always picked up by satellite or airplane observation.
这是因为与红树林和暖水珊瑚礁不同，海草草甸并不总是被卫星或飞机观测到。
英语百科
Pilot report
（重定向自Airplane observation）
A pilot report or PIREP is a report of actual weather conditions encountered by an aircraft in flight. This information is usually relayed by radio to the nearest ground station, but other options (e.g. electronic submission) also exist in some regions. The message would then be encoded and relayed to other weather offices and air traffic service units.