These seahorses were made in the 1940s-50s, likely from Southern California.  The artist name was Shirley, because each set is impressed "Shirley" and with a copyright symbol.  Nothing else is known about this ceramicist.  Like all Shirley shakers, they can be found in a variety of solid colors.  So far the seahorses have been found in blue, brown, and maroon.  Each set stands about 3'' in height with a typical 3-2 pour hole pattern.

Shirley seahorses salt and pepper shakers
Shirley seahorses salt and pepper shakers
Shirley seahorses salt and pepper shakers