Lake Sonoma Fisheries Biologists Jason Held and Mackenzie Odenwald work with small Coho Salmon as they tag the fish with Passive Integrated Transponder tags (PIT tags) and coded wire tags. PIT tags contain the same technology as the “microchips” used in pet dogs and cats, and are widely used in fisheries studies to track fish movement, survival, and growth over time. A coded wire tag contains a unique code that identifies an individual or group of fish that were released at the same place and time.