Rotenone and Live Gene Banking: Conservation and Rebuilding of Local Stocks after Treatment

Rotenone and Live Gene Banking.

Conservation and rebuilding of local stocks after treatment.

In order to preserve the genetic evolutionary potential of Atlantic salmon populations infected with G. salaris, the Advisory Committee of the Sea Ranching Program recommended in 1988 establishment of a Live Gene banking Program for all G. salaris infected salmon populations in Norway. Cryopreservation of salmon milt started two years earlier and G. salaris infected populations are now being stored for future generations and reestablishing programs after rotenone treatment.

Only the most seriously threatened salmon stocks, those that were no longer capable of surviving in their native river habitat, are preserved in the Live Gene Banking Program. Today, Norway has three different Live Gene Banking facilities for Atlantic salmon with 27 genetic separated wild salmon populations where the majority is or has been infected by G. salaries. Two more facilities are now being finished in order to supplement our need for extended capacity.

Atlantic salmon are captured from rivers as adults, and kept in nearby tanks for a short period, until milt and eggs can be stripped. Cryopreserved milt is then taken from the river and transferred to a central storage facility. Fresh milt and unfertilized eggs is transferred to a Live Gene Bank in order to be fertilized, disinfected, sorted in family groups and later individual marked for pedigree control and administration of genetic variability.  Once the rotenone treatment is finished, a restocking of the river system starts based on a Recovery Program to enhance the variability of the specific population. The main strategy is based on planting of fertilized disinfected eyed roe into the river habitat.

A case study of restoring the river Rana after rotenone treatment provide an example of how to design and implement a Gene Banking Program for restocking and rebuilding of wild Atlantic salmon populations after eradication by the introduced parasite G. salaris.