Cephalothrix simula - An invasive non-native toxic species of ribbon worm TTX tetrodotoxin

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One 147mm long mature specimen of Cephalothrix simula was found in a sample among the coralline algae Mesophyllum lichenoides and Corallina officinalis which were themselves attached to the shell of a live 45mm long Crepidula fornicata, a non-native slipper limpet. Crepidula fornicata originates from the east coast of the USA. Two terebellid worms, Eupolymnia nesidensis with tubes were also present among the algae, it is very likely this is the species the nemertean was feeding on. Specimen was found at Hannafore Point, Hannafore, Looe, Cornwall. 50.34281946635076, -4.453173449193521 on the 05.01.22.

This was the second instance of this toxic species being found in Cornwall, the other being the first physical instance of the worm in the UK at Godrevy Point, Hayle. IFCA, DEFRA, Cornwall Council (Environmental Health) have been notified given the toxicity issue that surrounds the toxin TTX which the worm contains at very high levels (Pufferfish neurotoxin). The toxin may be transfered when handling, but I have handled this species many times without gloves with no ill affects. However if the worm or its contents become accidentally ingested there may be significant problems. It is a bacteria, Vibrio alginolyticus, that lives within the worm that is responsible for producing the toxin.

Foraging does take place at Hannafore as it does at Godrevy Point where this worm is also found. On testing no TTX toxin was found in shellfish at Godrevy Point, probably due to the fact it is an exposed shore and is on the open coast, so there would be constant flushing of clean seawater. No TTX testing of shellfish has been done at Hannafore Point. TTX toxin is not destroyed by cooking. The risk of contamination is likely very small indeed if it exists at all, but it is impossible to say a risk does not exist.

On doing broad spectrum sampling of various habitats at Hannafore on 04.01.22 and 05.01.22 only one specimen was found. It is highly likely that they are there in some number BUT it appears either the species is not invasive at Hannafore, or its numbers have not had time to increase. That said Cephalothrix simula is largely a sublittoral species and therefore mainly exists beyond the shore so may only be found in number only on the lowest of low tides.

Cephalothrix simula is an invasive species and sadly we currently do not know the ecology of the toxin TTX that is produced within the worm by the bacteria Vibrio alginolyticus. We have no idea where in the food chain TTX may turn up and therefore the impact it will have on other invertebrates or higher species. It is critical that we do further research into environmental TTX, and well before we end up having a crisis that affects higher species, even ourselves.

See paper-
New Invasive Nemertean Species (Cephalothrix simula) in England with High Levels of Tetrodotoxin and a Microbiome Linked to Toxin Metabolism.

IMPORTANT PLEASE NOTE:
The identification of this species is by DNA sequencing only.
The reason for this is that there are two other morphologically identical species that exist in the Asian Pacific, but so far none of them have been identified in Europe. The species can also be confused with UK natives. A good knowledge of nemerteans is needed to even tentatively identify this species.
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APHOTOMARINE

An educational resource dedicated mainly to the photography
and diversity of marine life that can be found in coastal waters
and intertidal areas of Great Britain and Ireland by David Fenwick.

APHOTOMARINE

An educational resource dedicated mainly to the photography and diversity of marine life that can be found in coastal waters and intertidal areas of Great Britain and Ireland by David Fenwick.

An educational resource dedicated mainly to the photography
and diversity of marine life that can be found in coastal waters
and intertidal areas of Great Britain and Ireland by David Fenwick.