Unless a Millennial owns a cat, they're probably not buying canned tuna. The Wall Street Journal's research says that while 45% of people over the age of 55 regularly purchase canned tuna, that number falls to 32% for millennials. That means that the companies who make canned tuna should make the most of their customer base while they're still there - the future doesn't look rosy for them.
In a similar complaint to the one we saw from the fabric conditioner industry, the vice president of Skarkist (one of the major manufacturers) recently complained that Millennials 'don't even own can openers.' We don't think a lack of suitable tools for opening cans is behind this downturn though - the root of the problem probably lies in the fact that canned food is viewed as processed food, and is therefore perceived to be low quality.