This week we saw 5 Mola Mola on 1 dive in Lembongan so I thought that I would find out what a Mola Mola is, and the first thing I discovered is that the Mola Mola is the heaviest bony fish in the world!! (sharks and rays can be heavier, but they’re cartilaginous fish).
The Mola Mola, or ocean sunfish, resembles a big floating blob, and the adult has an average weight of 1,000 kg and is 180cm long (250cm fin to fin).
They may be extremely cute looking but pufferfish are the second most poisonous vertebrate in the world, after the golden poison frog. Certain internal organs, such as liver and eyes, and sometimes the skin, contain tetrodotoxin, a substance that makes them foul tasting and often lethal to fish.
We have been seeing loads of Blue Ring Octopus recently in Lembeh so we thought we would tell you a bit about them!
There are possibly 10 different species of blue-ringed octopus but only 4 have been formally names and all are inhabitants of asian-pacific waters:
They are one of the jewels of the ocean, with vivid blue rings visible over the body when hunting, courting or alarmed. The are only 12 to 20 cm (5 to 8 inches) long but are considered as one of the world’s most venomous marine animals. When the octopus is agitated, the brown patches darken dramatically, and iridescent blue rings or clumps of rings appear and pulsate within the maculae. Typically 50-60 blue rings cover the dorsal and lateral surfaces of the mantle. They hunt small crabs, hermit crabs, and shrimp, and may bite attackers, including humans, if provoked.
The blue-ringed octopus spends much of its life hiding in crevices. Like all octopuses, it can change its shape easily, which helps it to squeeze into crevices much smaller than itself. This helps safeguard the octopus from predators and it may even pile up rocks outside the entrance to its lair. In common with other octopuses, the blue-ringed octopus swims by expelling water from its hyponome (funnel) in a form of jet propulsion. If the blue-ringed octopus loses an arm, it can regenerate it within six weeks.
Blue-ringed octopus females lay only one clutch of about 50-100 eggs in their lifetime. The eggs are laid then incubated underneath the female’s arms for approximately six months, and during this process she will not eat.
After the eggs hatch, the female dies, and the young larval octopuses will then feed off of copepods, larval crabs and larval starfish until they are ready to move deeper into the ocean then reaching maturity and will be able to mate by the next year.
Once the larval octopuses grow to be one to two years old they produce eggs and continue the cycle. Like most octopuses, they have a lifespan of approximately 1-2 years
Despite this small size and relatively docile nature, its venom is powerful enough to kill humans. The venom is a neurotoxin called tetrodotoxin, it is also found in pufferfish and is 10,000 times more toxic than cyanide. The toxin is injected using the octopus’ beak and causes motor paralysis and respiratory arrest within minutes, leading to cardiac arrest due to a lack of oxygen.
It carries enough venom to kill 26 adult humans within minutes. Their bites are tiny and often painless, with many victims not realizing they have been envenomated until respiratory depression and paralysis start to set in.
Respiratory arrest can occur within minutes as the toxin blocks nerve transmission. Other symptoms include vomiting, muscle weakness and paralysis of respiratory muscles. Victims are fully awake until lack of oxygen, from the inability to breathe, leads to unconsciousness.
Tetrodotoxin causes severe and often total body paralysis; the victim remains conscious and alert, but this effect is temporary and will fade over a period of hours as the tetrodotoxin is metabolized and excreted by the body.
There is currently no anti-venom available, and victims are frequently saved if artificial respiration is started and maintained before marked cyanosis and hypotension develop. First aid treatment is therefore pressure on the wound and artificial respiration once the paralysis has disabled the victim’s respiratory muscles. Victims who live through the first 24 hours generally go on to make a complete recovery.
It is essential that rescue breathing be continued without pause until the paralysis subsides and the victim regains the ability to breathe on their own. This is a daunting physical prospect for a single individual, but use of a bag valve mask respirator reduces fatigue to sustainable levels until help can arrive.
Definitive hospital treatment involves placing the patient on a medical ventilator until the toxin is neutralized by the body.
It is essential that efforts continue even if the victim appears not to be responding. Tetrodotoxin poisoning can result in the victim being fully aware of their surroundings but unable to breathe. Because of the paralysis that occurs they have no way of signaling for help or any way of indicating distress. Respiratory support, together with reassurance, until medical assistance arrives ensures that the victim will generally recover well.
It may come as a surprise to divers but blue-ringed octopuses are common in very shallow water. As a result, children are probably most at risk as they are attracted to the vivid blue rings displayed by the octopus when threatened: the octopus is small and so is often picked up by inquisitive children. For divers, as always, great care should be taken when touching the reef as, when not threatened, the octopus’ camouflage can be very effective. They are not aggressive and their first form of defence is to flee.
The mandarin fish is one of the most beautiful fish in the ocean and their special mating display can be seen right here in both Bunaken and Lembeh waters!
• Scientific Name: Synchiropus Splendidus
• Found: Indo-Pacific Ocean (Philippines, Indonesia, Malaysia, Australia)
• Size: 1 -2 Inches
• Diet: Carnivore – feed on small worms, protozoans and small crustaceans
• Habitat: Broken coral rubble beds or under dead coral
• Depth: 1 – 18 metres
• The name comes from its fantastic colouration which resembles the robes of an imperial Chinese officer (Mandarin)
• They live in pairs and groups of up to 5
• Males have more orange colouration in their face and are larger in size with an elongated first dorsal spine. Females have smaller dorsal fins.
• Mandarin fish are distinctive due to their unusual shape and broad, depressed head
• One of its most remarkable features is their big outward-set eyes. This is an ideal adaptation for food hunting and feeding in the dim light environments underwater
• They swim with a rapid pulsating of their fins which tends to make them look like they are hovering, like a humming bird
• The mandarin fish is one of the few marine fish which does not have scales. As a protective compensation it is protected by a mucous-coated slimy and smelly skin, which not only protects them from most parasitic skin diseases, but also discourages predators due to its horrible taste. Their bright vivid coloration also serves to give out warning to predators of their nasty smell and taste.
• There is little information on specific predators of this species, although scorpionfish are known to lie in wait to attack an unsuspecting mandarin fish, normally during the mating ritual.
The mating of mandarin fish by spawning is something you HAVE to witness before leaving Bunaken!! Just before the sun sets, 3 to 5 females will make their way to a particular region of reef (“street corner”!) and gather where males visit and display courtship behaviour, hoping to attract the females. The visiting males may tour around various sites in one evening spreading their sperm among a number of different females!
A successful male will be joined by a female that will rest on his pelvic fin. The male and female mandarin fish align themselves belly-to-belly and together, slowly rise about 1 metre above the reef. Once they are at the peak of their ascent, they will release sperm and a cloud of eggs (usually up to 200 eggs). The fish then disappear in a flash. The fertilized eggs are from that point at the mercy of the current and normally take around 18-24 hours to hatch into 1 mm long larvae. For a period of up to 2 weeks they will remain plankton with no parental involvement before finally settling on the reef and choosing an appropriate habitat where they will live for the next 10 to 15 years.
With only a small number of active females in a group’s population, competition among the males is high. In the world of mandarin fish, size does matter! The bigger and stronger males tend to be favoured by females and mate more often than smaller males. Due to the lower chances of mating, the smaller males have developed a rather desperate compensating measure where they rush up to mating pairs and release sperm with the hope of random fertilization!
This is a ritual you can witness most nights here in Bunaken & Lembeh, and is a must for any diving enthusiast – ask your guide for more information!