Shrimp talent contest
Researchers at Australia’s Centre for Sustainable Tropical Fisheries and Aquaculture at James Cook University led by PhD student David B. Vaughan have held a talent contest to find the best species of shrimp for gorging on parasites that plague farmed fish.
In the wild, a type of crustacean called cleaner shrimp can be found picking off parasites from fish in exchange for access to some tasty morsels. But this relationship doesn’t occur in fish farms, where parasitic diseases can account for 30–50% of annual fish stock losses in spite of the use of antibiotics and insecticides.
Vaughan and his colleagues evaluated four shrimp species to find out if one of them might be up to replacing the industrial chemicals (Sci. Rep. 2018, DOI: 10.1038/s41598-018-32293-6). The snacking shrimp feasted with gusto on three harmful parasites—a monogenean fluke, a ciliate protozoan, and a leech—all present on a farmed species of grouper.
The contest winner was the peppermint shrimp. It successfully removed 98% of the pesky parasites. Unlike synthetic chemicals used to remove the parasites, the peppermint shrimp is also able to finish off the parasites when they are at their early-life phases in cysts, eggs, or cocoons.
Vaughan suggests the shrimp could be located on the outside of the fish farm nets, where they could have their lunch without becoming lunch. “The fish and the shrimp don’t necessarily always have to be in direct contact, which reduces the chances of them being eaten by the fish,” Vaughan says. The next step is to scale up the trial in the field at an aquaculture farm.
But not all shrimp are so clean living. In a recent investigation into the presence of contaminants in rivers in Suffolk, a rural county in the UK, 100% of shrimp tested positive for traces of cocaine (Environ. Int. 2019, DOI: 10.1016/j.envint.2019.04.038).
Many of the drug-consuming critters also tested positive for the recreational drug ketamine and the anesthetic lidocaine. The scientists were surprised by the presence of the substances in such a rural part of the country.
In all, the researchers detected a cocktail of 56 synthetic compounds in the Gammarus pulex species of shrimp, including pharmaceuticals, pesticides, and illicit drugs. The impact of the synthetic compounds on the shrimp and other biota is difficult to determine, the authors state. With a diet of antidepressants, painkillers, and recreational drugs, the shrimp could be among the happiest and most pain-free in the world. On the other hand, while no adverse effect on the shrimp was identified, these crustaceans could be suffering from the drug cocktail and be experiencing toxic pressure, the authors note.
One of the many illicit drugs found swilling around Suffolk’s waterways is (±)-3,4-methylenedioxymethamphetamine, also known as MDMA, or ecstasy. Learning how to make the substance isn’t usually on a university’s undergraduate curriculum, but illegal production of this Schedule I drug allegedly took place in 2013 during a class at the College of Pharmaceutical Sciences at Matsuyama University, according to Kyodo News.
Tatsunori Iwamura, a professor at the university, is under investigation for instructing 11 of his students to make MDMA despite failing to hold a license to produce the drug for academic purposes. The regional drug-enforcement authority is now seeking to prosecute Iwamura and 4 of his students.
The university is taking measures to ensure Schedule I drug production is no longer part of its schedule.
Alex Scott wrote this week’s column. Please send comments and suggestions to email@example.com.