HIROSHIMA, Japan, Aug. 25 (UPI) -- To better understand how lobsters safely consume jellyfish, researchers at Japan's Hiroshima University took a closer look at the shellfish's feces.
Larvae of the smooth fan lobster often ride around the ocean on jellyfish, slowly eating the gelatinous sea creatures as they're transported. Most of a lobster's digestive pathway is covered by the same protective shell that covers the outside of its body, but a portion, its "midgut," is exposed.
After feeding several young smooth fan lobsters, Ibacus novemdentatus, a meal of Japanese sea nettle tentacles, scientists quickly collected the freshly deposited lobster feces. With the help of a microscope, the researchers realized the feces were tightly wrapped in peritrophic membrane.
Though the peritrophic membrane is designed to be permeable, the new findings -- detailed in the journal Plankton and Benthos Research -- suggest the material is strong enough to protect the lobster's insides from the syringe-like tentacles of the jellyfish.
"Based on the contents of their feces, we think that the lobster larvae only digest fluid-type foods, which is vital to know as we develop an artificial food for farmed lobsters to grow efficiently and healthily," researcher Kaori Wakabayashi said in a news release.
Aquatic farmers have failed to find efficient and effective ways to raise lobsters. Additionally, the success of farm-raised mussels and other shellfish has led to a depletion of global sardine stocks -- the fish most commonly used as feed.
Researchers at Hiroshima are hopeful their findings will make farmed shellfish more sustainable as well as help aquatic farmers find a way to successfully raise lobsters.
"In the future, artificial food will empower farmers to provide their lobsters with convenient, sustainable, and safe nutrition regardless of weather, locality, or the availability of other marine resources," said Wakabayashi. "Knowing what the lobsters ate also ensures greater food safety for people."