I missed this message earlier. From the title of your posting it looks as if you are asking for a source of gelatine made from seaweed? Am I correct? If so, I would suggest you google edible seaweed manufacturers in Ireland as they seem to be the main source "locally".
If you want to get kelp products from the US, then Ryan Drum is your man. His website ishttp://www.ryandrum.com/
If you are looking for a source of gelatine from animals, then you're looking for gelatin from bones. If you're wanting it for arthritis, then bone stock is a good source.