PIT tag data are organized around data collection events keyed to the unique code of the implanted PIT tag. The first event is the initial mark event, when a tag is inserted into a live fish with the intention of releasing that fish into a Columbia Basin body of water. Once a PIT-tagged fish has been released that fish (or its PIT tag) can be involved in several other data collection events, such as being recaptured by a researcher conducting in-river tagging, recovered after the fish has died, or detected by automated antennas. The data from these events are managed in two separate streams based roughly on how they are collected: manual vs automated. Generally, mark/recapture/recovery (MRR) data are collected manually when researchers capture, anesthetize, and handle fish. Automated data collection occurs when previously PIT-tagged fish pass through or near equipment that can decode the unique PIT tag identifier and record the place and time of the detection.
Information from mark, recapture and recovery events is referred to as MRR data and follows the MRR data specification. Information from automated PIT tag detections is referred to as interrogation (or observation) data and conforms to the interrogation data specification.
The presence of an uniquely identifiable tag that can be detected automatically without capturing or handling the marked fish provides another research opportunity on the Columbia Basin. The Separation by Code (SbyC) process allows researchers to target individual tagged fish and separate them from the general population as they move through juvenile and adult fish passage facilities that are equipped with PIT tag actuated gates. This allows researchers to target a specific release group for recapture and reevaluation of their condition since the initial mark event. It also allows for fish to be separated into different treatment groups at those facilities where fish are transported downstream.