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Topic
- Izaak Walton League of America 45
- Rivers--Oregon 18
- Water--Pollution 14
- Lectures and lecturing 10
- Conservation of natural resources 6
- Dams 6
- Fishes--Conservation 3
- Forests and forestry 3
- Oregon Cavemen Inc. 3
- Portland Chamber of Commerce (Or.) 3
- Sewage disposal plants 3
- Agriculture 2
- Algae 2
- Birds--Conservation 2
- Oregon Audubon Society 2
- Salmon 2
- Wildlife conservation 2
- Wildlife management 2
- Wildlife refuges 2
- sardine 2
