I agree with the other commenter, doesn't really seem to matter in this setting. Colloquially, "decibel" is a widely known scale ranging from "I can barely hea

I agree with the other commenter, doesn't really seem to matter in this setting. Colloquially, "decibel" is a widely known scale ranging from "I can barely hear that" to "holy crap, that's loud". 140 decibels communicates this fish is capable of a surprisingly loud sound - which is surprising. I don't really care if it's entirely accurate. I simply know that it's "surprisingly loud".