Hi Randy,

the source of the speculative date is Japanese records. According to a report, an Ominato-based seaplane on patrol in the area of Shiriya saki (Aomori-ken, NE Honshu), sighted an attacked a surfaced submarine on 17/9. The sub returned fire then dived. Oil was seen by the plane on the surface following its attack. The minelayer Ashizaki arrived at the scene the following day and dropped depth charges which brought more oil to the surface.
It is possible that Pompano survived the plane attack only to detonate a mine while attempting to make her escape underwater, though no explosion was observed by the aircraft, the surfacing of a fair amount of oil would tend to indicate that Ashizaki's DCs did indeed find a target, but as said above, short of locating the wreck, there is no way of knowing whether this attack was the one who sank Pompano or not.

Brian C:
the loss of Taiko maru is a strange affair. She is usually considered as a victim of Pompano, but you are correct in saying she was outside her allocated area. Any idea why would the sinking be credited to Pompano rather than Wahoo?

Regards, Brian V.