Crown Prince was one of the first cans of no salt added I found and it is good. Here is some helpful information about tuna and mercury. Light tunas (skipjack and tongol) typically have lower levels of mercury than white tunas (albacore and yellowfin). The “light” labeling isn’t always 100% accurate about this.
Try to find some indication that the tuna is either skipjack or tongol if you want lower-mercury tuna. Give it a try and enjoy!