How to map data from USGS NAS database, using HUC?

I am querying the USGS NAS (Nonindigenous Aquatic Species) database. The collection data for the results that are returned don't include lat/long points, but have an HUC (Hydrologic Unit Code). I have no idea where to start in terms of mapping this information with HUCs. I've done some searching, but to no avail. I'm wondering if someone could give me a nudge in the right direction or offer any advice? Here is the query I'm working with right now: http://ift.tt/1Kgoh9l

I'd really appreciate any help. Thanks for looking!