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PIT tagging of fi sh benefi ts aquaculture breeding programmes among other applications
by Eurofish
PIT tagging of fish benefits aquaculture breeding programmes among other applications
Tracking and tracing individual specimens
Monitoring fish by tagging them was initially used by fisheries managers of capture fisheries to gather information about the stocks they were managing. Today the same techniques can be used by the aquaculture sector to follow broodstock, monitor feed trials, prevent inbreeding and generate data on growth rates and fish welfare.
Marking fish with PIT (Passive Integrated Transponder) tags is a very common practice in conservation projects, especially for migratory species including salmon, trout, sturgeon, and barbel. This monitoring practice, named PIT tag telemetry, received a huge boost during the 1990’s in the northwest of the United States. PIT tag telemetry played an important and essential role in the recovery of the salmon population along the Columbia River basin and its major tributaries.
Large PIT tag telemetry antenna installed in the riverbed for fish migration monitoring.
Information from tags makes for better stock management
Fixed monitoring stations (or antenna systems) combined with mass fish tagging allowed improvements in dam passage, smolt downstream migration, and greatly reduced mortality due to anthropogenic impacts. The ability to recognize each individual PIT tagged salmon improved knowledge about fish population dynamics and allowed fisheries managers to take real time decisions about the best instance to open or close the fishing season. Roughly 30 million fish have been tagged through the last 30 years and they have generated a huge amount of information that is used to optimize wildlife management. Recently, the same approach has been used in the aquaculture sector. Breeding programs, feed trials, parental selection, inbreeding: all require the easy identification of individuals. Identifying fish individually by scanning internal RFID PIT tags can be interesting for multiple purposes. Broodstock fish with a well-known genetic background, that will be used to breed for many years, are the most used application in aquaculture. Besides that, experiments where fish need to be identified individually can generate useful information on growth and fish health. PIT tagging is a very fast way to mark fish that would otherwise be indistinguishable from each other. The most common size of PIT tags, used in aquaculture, is 12 x 2 mm or 8 x 1.4 mm. An international organization, ICAR (International Centre for Animal Recording), provides unique codes to tag manufacturers and sets standards for the global market. More than 130 members from 55 countries around the globe actively participate in this standardization process.
In 1995, two ISO standards were created to regulate tag production to make this technology compatible around the world. This was a fundamental step in animal identification and more importantly in the international traceability of food and in sustainable food chains. When PIT tagging fish in aquaculture operation (as in the conservation sector), it is of fundamental importance to properly implant the PIT tag so as not to alter behaviour and performance of the tagged individuals. The final goal of a tagging session is not to have “zero mortality” but to make sure that marked fish behave like untagged ones. The EU Regulation 63/2010 introduced the “need for proper training” of personnel when working with individuals for “scientific purpose”. This training is well understood and partly adopted within the conservation sector but is still a grey zone for aquaculture operations. However, fish tagging training is highly recommended as the best fish from a genetic perspective can be obscured by improper tag position, affecting
