To answer your second question:
If you want to know many “aquaman comics” there are, I would suggest visiting mycomicshop . com
The current run (known as the re-birth era) are issues 1-55 (2016-Aug to now)
Before re-birth era, we had the new-52. Guess what, it only ran for 55 issues. (2011-Nov to 2016-July)
Series 4 has 57 issues (2003-Feb to 2007-Dec)
Series 3 has 75 issues (1994-Aug to 2001-Jan)
Series 2 was only 13 issues (1991-Dec to 1992-Dec)
Series 1 has 63 issues (1962-Jan to 1978-Aug)