I like the crab theory. Maybe Delta fish eat mitten crabs? I saw a largemouth on a bed at the Quarry Lakes once take a fist sized mitten crab in it's mouth and carry it off the bed. So clearly bass and mitten crabs interact at some level.

Maybe this explains why mitten crabs never caused the environmental disaster they were supposed to on the Delta. Maybe largemouth bass saved the Delta from all out destruction!!! Maybe jaundice bass holds the key!!! LMAO.