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Topic
- Izaak Walton League of America 13
- Lectures and lecturing 10
- Rivers--Oregon 7
- Conservation of natural resources 6
- Dams 4
- Fishes--Conservation 4
- Water--Pollution 4
- Salmon 3
- Flood control 2
- Hunting 2
- Wildlife management 2
- Wildlife refuges 2
- Algae 1
- Birds--Conservation 1
- General Wildlife Federation 1
- Irrigation 1
- Lakes--California 1
- Lakes--Oregon 1
- Migratory birds 1
- Sewage disposal plants 1
