Elastomer Tags to Be Tested For Use in Identifying Broodlines
BY JORGE BUENING, GENOA NFH
In the wild, genetic variability between parents over multiple years of reproduction makes sure that populations stay healthy and are able to adapt to environmental changes. This is a criteria that we strive to meet with our fish production at the Genoa National Fish Hatchery. To do this, we collect wild fish every three to four years and integrate them with fish from our production lots. A problem arises when trying to distinguish hatchery fish and wild fish or the various year classes that these broodlines are made up of. This is where marking the fish can be helpful.
Traditionally, fin clipping was done as our marking technique. This is a technique where combinations of the fish’s fins are clipped off. Based on these clips the origin and age of a specific fish can be identified. Fin clipping is not harmful or painful to the fish; it is similar to us clipping our fingernails. However, there are problems that arise with fin clipping; one of those is the possibility that the fin regenerates without leaving any trace of the clip. This basically puts us back where we started. There is also the risk of infection or fungal growth stemming from the clip site. For these reasons we are looking for new marking techniques that could be used in maintaining our broodlines.
One alternative method is the use of elastomer tags. This is essentially injecting a very colorful plastic into the fish’s skin. Based on the elastomer color and location the fish can be identified. The hatchery is planning to test both green and pink elastomer colors in both the fishes jaw and along the dorsal fin. This test will allow us to determine which color and location persist in the fish the longest as well as determine if it is a viable option for marking our broodlines.