The commercial pier where the cruise ships dock is not for tourists. It is a dangerous commercial area with cranes and heavy equipment. It isn't for walking.
In addition during the time we were there, an ammonia refrigeration plant on one of the tuna boats exploded, killing several people and causing injuries to others. The port was closed for a period of time for emergency vehicle access.
You have to be careful at night. don't want to scare nobody but do not walk alone in the streets. groups are good. don't wear flashy jewlery it will be snatched. try to stay in tourist areas. be safe when venturing in unknown areas. take a taxi it is safe and they only charge like 1 or two.