"The Fisherman of Falcon Point"

by August Derleth
originally published The Shuttered Room and Other Pieces, Arkham House, 1959

 Enoch Conger is a grumpy local fisherman who no one likes very much.  He tends to hang out in a tavern near Innsmouth.  One night he tells a tale of fishing up a "mermaid" sort of thing off Devil's Reef.  The "mermaid" promised to save his life someday, if he would let her go.  This gets him laughed at.  After that, Conger doesn't come around much - mostly just keeps to himself, staring out at the ocean.

Conger is found injured.  He asks to be carried back to his tiny house at Falcon Point.  When a doc arrives, Conger is gone.  But webbed footprints are found outside.  Conger is never seen again - except local salts who sometimes report seeing him swimming with schools of Deep Ones, singing hymns to Dagon...

Obviously a very minor story.  Still I have always found this one entertaining and evocative in its slight way.