posix script/perl script

i’ve thousands of directories with this file structure. i want to loop through all the directories to look for files having format like 8889@3-000 & 3930@3-023 and get the prefix (i.e. 8889, 3930) to create new empty files. e.g.

BEFORE
——-
abc:
8889@3-000
3930@3-023
testjob
parameter/

AFTER
——
abc:
8889
3930
8889@3-000
3930@3-023
testjob
parameter/

how do i do it in posix/perl?