Splendid Reef Crab Etisus splendidus
The Splendid Reef Crab grows to 30 cm (12 in) and spends the day hidden in the dark labyrinths of coral and rocky reefs in the Indo-Pacific.
Solitary in habit, it ventures out at dusk to the undersides of ledges and holes in the reef in search of the Algae on which it feeds.
During twilight the Splendid Reef Crab is never fully exposed and is very sensitive to movement. However, on moonless nights it will move into the open to feed. It is fairly slow but extremely powerful and clings to the substrate tenaciously when caught.
After finding and photographing this crab I fortunately didn’t take it back for dinner, my saving grace, the fact that I was loaded down with all my cameras and not able to carry the crab on the long snorkel back to the boat.
HAZARD:
Deadly poisonous to eat.
PRECAUTIONS:
Although this Crab is big and looks as though it would make a good meal, never eat any Reef Crabs with black nipper tips, as they are all poisonous, due to their habit of feeding on Coralline Algae, as can be seen in the first image.
Devil Reef Crab - Zosimus aeneus
One of the most deadly poisonous crustaceans the Devil Reef Crab grows to 15 cm (6 in) and well known across the Indo-Pacific region for its toxicity.
Records show that as little as half a gram of flesh from the large claw is sufficient to kill a human!
Cooking does not eliminate or dissipate the poison and in its pure state 1 milligram of this saxitoxin can kill 5000 mice.
The poison is a neurotoxin which blocks signals to nerves and prevents muscles from functioning, causing asphyxiation. Unless artificial resuscitation is available, death is inevitable.
Colour variation from the northern Great Barrier Reef. The saxitoxin poison is actually formed inside the cells of certain Dinoflagellates. The Dinoflagellates are either on the substrate that the Crab feeds on, or they are eaten by some species of detritus feeding Mollusc. The poison is accumulated in the Mollusc and the Crab feeds on the Mollusc and becomes a carrier of the poison.
HAZARD:
Deadly poisonous to eat.
PRECAUTIONS:
Never cook, or eat this species of Crab, or drink broth made from this Crab. It is deadly poisonous.
SYMPTOMS:
The seriousness of the symptoms are directly linked with the amount of saxitoxin consumed and absorbed.
A victim can feel tingling in the tongue and lips within 15 minutes and both may become numb; the hands also may be affected and limbs become weak. The condition develops an anti sensation, where cold feels hot, and hot feels cold and taste reverses from sweet to sour.
Eyes can become affected; including blurred vision and double vision; with pupils becoming fixed and dilated.
Coordination is also uncertain, with dizzy spells, and clumsy movements; drowsy feelings as if thick-headed, and problems with speech and swallowing, with parched feelings in the throat and a burning stomach. Salivation, thirst, severe vomiting and diarrhoea.
Respiratory failure and coma could follow and death can follow from 4 to 12 hours after ingestion.
FIRST AID:
Reduce shock and reassure patient at all times.
Contact Emergency Medical Assistance ASAP.
Vomiting to be induced as symptoms appear.
Do not induce vomiting once paralysis has developed as there is a high risk that vomit could block air passages.
If in the open, block eyes from the sun to shade the retinas from being burnt.
Any reduction or lapse in breathing should be countered with expired air resuscitation (EAR) and continued until medical assistance arrives.
Patient should not be left alone and regardless of appearance, reassurance should be continued.
Seek Emergency Medical Assistance.
At no time should casualties eat seafood, extracts of seafood, alcohol, some black sauces, nuts or nut oils as any, or all of these may bring on ciguatera syndrome symptoms due to acute sensitivity and allergic reactions. There is no guarantee that prolonged allergy to seafood will not continue for many years.