There has to be a better way, but this is another example of criminal waste. I am from Newfoundland, and from the perspective of smallboat inshore fisher persons, it is usually part of their ground fish license. Cod, and if we are lucky enough, crab, are the majority of their license, lumpfish usually supplements their quota.
I was always flabbergasted to see them cutting the lumpfish bellies open and scooping out the roe. There was usually about a pound or so, and they threw away the remainder. Most lumpfish come in at 10 - 15 pounds, so it was so sad to see all these fish going over the side of the wharf to let the scavengers eat the rotting flesh.
Don't blame the fisher persons. They are just trying to make a living and that is the system. Remember this is only the females, so the males are thrown over the side of the boat when they are caught, many of which usually die because of the process of hauling the nets through hydraulic rollers called a "Girdy".
In vast majority of outports in Atlantic Canada, there usually is no system of collecting the scrap fish and processing into products ie pet food or fertilizer. And don't even get me started on other species like female capelin or undesirable fish from draggers. Such waste, with such a large part of population hungry.
I would imagine that most other countries are similar. And the same people who usually eat roe (caviar) "wealthy 1 percent,” are against the seal hunt. And guess what they eat -- and from experience, only the bellies, letting the fish die and sink to the bottom.
Sorry for making this into a bit of a rant, but what a screwed up world. Anyway, that's the lumpfish saga. Cheers.