Sodium sulfite has been used for a couple of decades as a dessicant/curing agent for turning fresh-caught salmon and steelhead roe skeins into cured fishing bait. However, over just the past few years, the sulfite has been proven to be toxic to small trout and steelhead smolts, so its use as a bait cure is now being regulated in my state. ODFW Fishing with Cured Eggs