In Croatia, Ciuk families are Croats (from the Island of Losinj ). In the past century, relatively most of Croatian residents bearing this family name were born on the Island of Losinj.
Prevalence
Only a few people with faimily name Ciuk live in Croatia today, in three households only. They are located in three Croatian cities only: in Cres on the Island of Cres (<5), Zadar (<5), and in Mali Losinj on the Island of Losinj (<5).
In the sources analysed in the project Acta Croatica so far, the name is mentioned over twenty times, the first time 1902 in source Hartmann's General List of Apartments in Zagreb.