Fertilizer would appear to be the logical solution. Compost a giant pile of them for six months and apply to fields.
Also let them rot into methane and burn the methane (probably combined with option 1 above).
You can't make a decent compost with pure 100% jellyfish, but added to another waste deficient in different nutrients, it might add up.
The article didn't discuss weaponization of jellyfish, which is the most likely funding source. Shutting down a regions desal and power plants by releasing a short lived poorly adapted jelly is a lot less visually impressive than a bombing campaign, but probably a lot cheaper. Or rather than the animals themselves, dump food for them, perhaps.
This would make for an interesting experiment. Anaerobic digesters would presumably make short work of any toxin proteins, and you could probably get a fairly high jellyfish to "other" feedstocks [ratio] while retaining a commercially viable fertilizer (plus plenty of usable methane) as end products.
That said, I doubt that the cost to harvest and transport would be competitive with more conventional feedstocks such as slaughterhouse leavings, crop wastes / stalks, and plain old manure.
Food for thought, anyway. Floating digester platforms, maybe?
Also let them rot into methane and burn the methane (probably combined with option 1 above).
You can't make a decent compost with pure 100% jellyfish, but added to another waste deficient in different nutrients, it might add up.
The article didn't discuss weaponization of jellyfish, which is the most likely funding source. Shutting down a regions desal and power plants by releasing a short lived poorly adapted jelly is a lot less visually impressive than a bombing campaign, but probably a lot cheaper. Or rather than the animals themselves, dump food for them, perhaps.