Researchers at the Children's Aquarium at Fair Park in Dallas, TX were curious what would happen if they fed their jellyfish a mix of seawater and peanut butter. Why? Well... two reasons, really.
Above: A moon jelly on day one of the experiment by Montoya and Christie via NatGeo
According to aquarist P. Zelda Montoya and aquarium supervisor Barrett L. Christie, one reason was for the obvious pun-tential:
...we would love to claim we conducted this trial with noble purpose, but the truth is that we just wanted to make peanut butter and jellyfish simply to see if it could be done. Whether or not it should be done is a question no doubt to be debated by philosophers for the ages (or at least by some aquarists over beers). We herein report on what we believe to be the first known unholy amalgamation of America's favorite lunchtime treat and live cnidarians.
But before someone gets on the phone with IUCAC about Montoya and Christie's frivolous treatment of the zoo's jellyfish, here's the second, more important reason for this investigation: Research has determined that the use of fish and shrimp as a protein source in marine-feed is an unsustainable practice. Seeking out cheap protein replacements is therefore vital to the future of aquaculture. Ground peanuts have shown promise as a cheap and effective protein replacement for "marine animal protein" in diets provided to sea creatures in captivity, like shrimp and finfish – so while Montoya and Christie's writeup of the experiment comes across as pretty blithe, it's not actually as out there as it sounds.
Plus, it actually appears to have worked.
Montoya and Christie emulsified creamy peanut butter and seawater in a blender and fed it to ~250 of the zoo's young moon jellyfish (Aurelia aurita). The pair then monitored the jellies' early development, and found two things.
One: the jellyfish took on a distinctly brown color immediately after feeding. (Pictured above are two moon jellies. The one on the left is in a contracted state and has just been fed, hence its brown-ness.)
Two: While their growth rates have tapered slightly compared to normal jellies, the PB-fed specimens appear to have developed "on-par with normal A. aurita outgrowth."
Montoya and Christie intend to continue raising the jellyfish to see if they can reproduce successfully. They make no mention of a followup study in their writeup of the experiment, but it wouldn't be a bad idea. Montoya and Christie's investigation lacked a control group. There was also no variation of ratios in the peanutbutter/seawater mixtures, which there really should be if you're trying to strike a balance between cost-effectiveness and the health of the animals you're raising. This experiment may have started out as something of a joke – but it doesn't have to end that way.