I've strong interests in Functional and Logic programming and Mercury seems like a good blend of the two. Is it used in industry at all? I'm one to learn a language just for the fun of it but it would nice to have practical, employable avenues for it. I could not find much in the way of examples of use in industry on the language website.
Mercury is a souped up Prolog, but logic languages are very niche in the industry, and moreso than functional languages. Dynamic scripting languages like Python, Ruby, and PHP, and languages like Java and C# will dominate most of what employers are looking for. The landscape seems different in Europe and Australia, but only slightly.
That said, there are companies that use Mercury, though I only know of two: YesLogic, which makes PrinceXML. They are located in Australia. The other is Mission Critical IT, which is based in Brussels and Australia.
Searches on major job sites like indeed.com, glassdoor.com, monster.com, and also on careers.stackoverflow.com did not turn up Mercury-specific jobs.
However, having skills with Mercury, you can probably parlay them into working at places where Prolog has been traditionally used, like in AI.
But I think the language will mostly be niche, like Haskell. There will be a few companies here and there using it, but the interest will remain strongly in academia and research.