I climbed it in ’76, but hadn’t fished any of the lakes in the blast zone when the mountain erupted. From what I’ve been able to gather, fishing wasn’t too much different then it is now. For the decade or so after the blast fishing in many of the lakes that had been overpopulated with naturally reproducing fish was improved with the influx of nutrients and reduced populations, but most of those lakes have returned to their pre-blast overpopulated status.