Grass Puffer Fish Communicate with Each Other Using a Non-toxic Version of their Deadly Toxin
Published:27 Nov.2022    Source:ScienceDaily
Puffer fish (fugu) contain a lethal toxin. Improperly prepared puffer fish can cause the person eating it to experience food poisoning and a swift death. Such a terrible event can happen because the fish's liver and ovaries contain a powerful neurotoxin called tetrodotoxin (TTX). However, though its purpose is unclear, puffer fish also have analogs of TTX that are non-toxic. Now, in a new study published in Scientific Reports, researchers have proposed that puffer fish use these toxin analogs to communicate using smell.
To conduct their research, the group used a kind of puffer fish called a grass puffer (Takifugu alboplumbeus). Grass puffers are a problem for many Japanese recreational anglers as they are considered bycatch that eat bait and break fishing lines. But at the same time, many people show affection towards them because of their appearance and a few people even keep them as pets. Many people also know grass puffers for their gathering at a specific spot on the evening of high tide in early summer and spawning en masse.
Pheromones are chemicals that are perceived by fish using their olfactory senses and are used to affect the behavior of others of the same species.Like other puffer fish, the grass puffer accumulates the neurotoxin TTX to discourage would-be predators. However, grass puffers also accumulate a non-toxic analog of TTX called 5,6,11-trideoxyTTX (TDT). Scientists are curious as to why pufferfish should accumulate a non-toxic version. To better grasp this phenomenon,researchers investigated the compound. They established that TDT serves as a smell that attracts other grass puffers and identified the olfactory sensory cells that they use to sense it.

The  results provide a new perspective on the use of TTX and its analogs by toxic puffers. They are the first clarification of the biological functions of the non-toxic analog and are expected to have a meaningful impact on research on the toxification mechanism and reproductive behavior of pufferfish.