Tags of the Trade

Scientists have been trying for hundreds of years to study fish movements. These researchers would sometimes clip fins or secure a chain around the tail to mark individuals. Interestingly, similar techniques are still used today; fins are clipped to differentiate wild salmon from those raised in a hatchery. The value of mark and recapture is several fold; if we know where an individual fish is at two different times we can obtain important information on migrations, abundance, stock structure, mortality and growth rates. Many of these parameters are integral to fisheries models upon which management is based. Thus, to develop adequate management, it is critical that we have a handle on these aspects of basic biology.

As many other fields, research of fish movements has been propelled into the future as a result of technological advancements and miniaturization. While some of the old methods are still applied and very useful, new tools are allowing scientists to ask much more complicated questions about fish in their natural environment. We can essentially follow the fish on its travels through the seas without ever getting wet. Below, four of the common tools used to study fish movements are described, ranging from old to new.

PIER researchers use many different methods in their tracking and movement studies:

• Conventional Tags
• Pop-up Satellite Tags
• SPOT Tags
• Acoustic Tags
• Archival Tags