Consumption of canned tuna has dropped over the past three decades.

Industry experts told The Wall Street Journal that this is partly because millennials want their food to be as convenient as possible, and in some cases, opening a can is too much work. Some may not even have the appropriate utensils to open the can.

The trend of convenience has created a boom for food-delivery companies. In a recent research report, UBS estimated that by 2030, online food delivery could command 10% of the total food-services market. That would translate to $365 billion in market share, up from $35 billion today.

Canned tuna is apparently falling out of fashion.

The Wall Street Journal reported on Sunday that per-capita consumption of canned tuna has dropped 42% in the last three decades, while consumption of fresh and frozen fish has risen in that time, according to data from the US Department of Agriculture.

Industry experts told The Journal that a combination of factors is behind canned tuna's slowdown, including a shift toward more convenient styles of cooking, millennials opting for fresher foods, and some not even having the appropriate utensils to open cans.

"A lot of millennials don't even own can openers," Andy Mecs, vice president of marketing and innovation for StarKist, told The Journal.

As a result, StarKist has been leaning in to its pouched products. The company told The Journal that sales of tuna pouches are growing 20% annually and are now more popular than cans among young consumers.

Read more: Millennials are cooking less and less, and it could cause a crisis for America's biggest food companies

Convenience has become one of the fundamental requirements of food for millennials, and that has put a lot of pressure on traditional food brands and created a boom for food-delivery companies.

A recent research report from UBS entitled "Is the Kitchen Dead?" explored how the growth of food-delivery apps could mean that no one does their own cooking at home in the future.

The report estimated that by 2030, online food delivery could command 10% of the total food services market. That would translate to $365 billion in market share, up from $35 billion today.

"Online ordering has started to become the norm, thanks to the convenience, accuracy, and ability to integrate payments," the UBS analysts wrote. "At scale, ubiquitous on-demand and subscription delivery of prepared food could potentially spell the end of cooking at home."