New alien marine species in the Med may pose threat to intrinsic species

It’s no secret that global warming can cause unwelcome changes in different regions of the world, with some species finding themselves comfortable in territories that otherwise might not have been so hospitable to them in the past due to inconvenient temperatures.  

One such species is the toxic silver cheeked toadfish, which was first caught in Maltese waters last summer. 

“The species originally and typically inhabits the considerably warmer Indian and Pacific Oceans, but its presence in the Mediterranean points to the possibility that these waters are becoming warm enough to host tropical fish,” Alan Deidun, professor in physical oceanography at the University of Malta, told MaltaToday.

Deidun explained that the silver cheeked toadfish is not however, the only species of its kind, with the Mediterranean holding over 1,000 so called alien marine species. 

“Little is, in fact, known about the possible consequences these species could have on existing ecosystems, or how they can be used profitably if caught.”

The identification process for the silver cheeked toadfish caught last year took so long because there are some eight different puffer fish species present in the Mediterranean, and although they are not all toxic, they all have very similar qualities.

“The silver cheeked toadfish is actually only toxic if it is ingested; but its strong neurotoxin can be fatal at times as it can lead to paralysis, and it always leads to hospitalisation,” Deidun said. 

He explained that even in Japan, where the fish is considered a delicacy, long and extensive training courses are required to learn exactly how the fish can be safely cooked and eaten.

The fish has been present in the Mediterranean since 2004, and it has spread considerably throughout the area, after having accessed the waters through the Suez Canal. 

“The fish has spread so much it was also sighted in Spanish waters recently, and although there is no official research on the fish’s presence in local waters, I suspect there is a small population,” Deidun said, explaining that in other countries like Tunisia and Italy, the presence of one fish was followed by many others like it being caught in quick succession. 

Deidun stressed that it was important to carry out research into the topic and raise awareness both with fishermen and consumers.  

“Countries like Italy and Tunisia are currently running public awareness campaigns to warn the public about the dangers this fish could pose, but there is nothing of the sort on a local level yet.”

Deidun said that since not a lot of research had been done to look into these fairly recent additions in the Mediterranean ecosystem, few of the species were known to be particularly damaging, but little to nothing was known about others. 

“The nomadic jellyfish is an example of an alien species which came to the Mediterranean in the 70’s. This jellyfish is very common in the Eastern Mediterranean countries and it has been known to close off beaches and clog fishing nets, as well as water pipe systems in power stations in Israel for instance,” Deidun explained. 

He added that around two specimens of the species had been seen in Malta, but there was no evidence that it was present in large quantities. 

“This species in particular can have a strong socio-economic impact, and although the effect of all alien species is not known, one thing is indisputable; they are competing for the same resources that other intrinsic species could need,” he added explaining that around one sixth of the fish in the Mediterranean were thought to be alien species. 

“Furthermore, Maltese consumers are not yet aware of how these ‘newer’ species can be cooked if they end up being caught by fishermen,” Deidun said.