A certified person on board fishing vessels who collects scientific and technical information on the fishing operations and the catch. Observer programs can be used for monitoring fishing operations (e.g. areas fished, fishing effort deployed, gear characteristics, catches and species caught, discards, collecting tag returns, etc. ). Observers may or may not have legal coercion powers and, their data may or may not be used for nonscientific purposes (e.g. enforcement) depending on the situation.