The author, who wrote Heartbeats in the Muck, makes a point that applies everywhere:
Mitigation for the loss of wild runs of these fishes was most often in the form of the easy but nearly always ineffective — if not downright destructive — stocking of hatchery-reared specimens. The exquisitely fine-tuned life histories of natural runs to their home rivers became quashed by mass-produced specimens that were less fit, but that nonetheless competed with any remaining wild individuals, reducing their fitness, too, as they interbred. Responsibility for the continuity of the runs shifted away from maintaining ecological integrity of fish runs and rivers to what amounted to a cosmetic patch via outsourcing. Abundant research has shown that a fish is not a fish is not a fish.