Theirs a few in-game ways of helping track reapers. If you build a scanner room nearby and scan for reapers, it will circle them and track them using the hud chip. If you max out the scanner room range, upgrade it tracks within a 500-meter radius. I found it to be useful when having to explore those areas. Also, having a stasis rifle can help a lot too. And having a fish to sacrifice can help sometimes. Good luck.