Manta Rays

Manta Rays: Their Life Cycle and Why They are Vulnerable

by Fahmi, AMD-B’s 2024 Divemaster Intern

Manta rays have a unique but slow reproductive process. Female manta rays give birth to live pups after a pregnancy lasting about a year. What makes them vulnerable is that they typically produce only one pup at a time and may take two to five years before reproducing again. Once born, the pup is left to survive on its own and spends nearly a decade growing and maturing. This slow reproduction rate means manta populations struggle to recover when their numbers are reduced.

Manta rays are highly migratory creatures, travelling vast distances in search of food and suitable habitats. While this behaviour is essential for their survival, it increases their exposure to various threats. Overfishing, entanglement in fishing gear, and habitat destruction—such as the loss of coral reefs that serve as feeding or cleaning stations—pose significant risks. Climate change and pollution also impact the plankton populations that mantas depend on for food, making their survival even more challenging.

Manta-Rays-Life

Why Manta Rays Matter

Although manta rays do not have a massive ecological role compared to species like sharks or corals, they contribute to marine tourism in a significant way. Destinations like Nusa Penida and Raja Ampat attract divers and snorkellers eager to witness these majestic animals. The revenue from manta ray tourism supports local economies and often funds conservation projects, creating a positive cycle of benefits for both humans and the environment.

Manta-Rays-Matter

The Importance of Protecting Manta Rays

Manta rays are not just symbols of marine biodiversity; they are also indicators of ocean health. Their vulnerability reminds us of the delicate balance in marine ecosystems. Protecting manta rays is not only about saving a species—it’s about safeguarding the health of our oceans, promoting sustainable tourism, and respecting the interconnectedness of life underwater.

Protecting-Manta-Rays

Nudibranchs

Nudibranch

When it comes to shapes and colours, the variations found in nudibranchs never ceases to impress underwater photographers – and the rest of us!

There are over 3,000 species of nudibranchs worldwide, with new ones being identified regularly. These fascinating creatures are hermaphrodites, meaning they can mate with any individual of their species. Another intriguing fact is that nudibranchs are carnivorous, with diets that go beyond corals, algae, anemones, and sponges—they may even consume other nudibranchs.

Nudibranchs in Indonesia

To help you get started, here are five fantastic nudibranchs to look out for in Indonesia:

Nudi-Hypselodoris-Bullocki

Hypselodoris bullocki – This species, found in Bali, Lembeh, Triton Bay, Wakatobi, and Ambon, is famous for its lavender hue and dark spots. It’s a beautiful find for those who appreciate subtle but striking patterns.

Nudi-Chromodoris-Magnifica

Chromodoris magnifica – As its name suggests, Chromodoris magnifica truly stands out. You can find this bold nudibranch in places like Raja Ampat, Ambon, Halmahera, Lembeh, and Bali. Its eye-catching combination of orange, white, and black makes it a favorite for underwater photographers.

Nudi-Nembrotha-Kubaryana

Nembrotha kubaryana – Known for its dramatic blend of black, green, and orange, Nembrotha kubaryana is another species divers love to spot in Wakatobi, Bali, Lembeh, Raja Ampat, and Alor.

Nudibranch-Doto-Greenamyori

Doto greenamyori – This unique species has earned the nickname “Doughnut Doto” because of its shape. Doto greenamyori can be found in Tulamben, Wakatobi, and Misool, often hiding among hydroids and other small organisms.

Nudi-Thecacera-Pacifica

Thecacera pacifica – With its bright yellow color and black markings, this nudibranch resembles the famous character Pikachu! You can find it in Bali, Triton Bay, and Alor.

Please note: The above are the areas which offer a high chance of seeing these particular nudis. This being Indonesia, you can find the most unexpected species far outside their known range, for example:
– While diving with AMD-B, Dr Richard Smith (Ocean Realm Images) found displaying male McCosker’s flasher wrasses 2,500km east of their previously recorded range
– Okenia liklik nudis in Tulamben Bay, Bali (previously only recorded in Papua New Guinea and Luzon).

There are many other super-rare nudis that are scattered throughout the ocean so, who knows, maybe YOU will be lucky enough to find a new species and contribute to naming it 🙂

The Mimic Octopus

Mimic Octopus a.k.a Thaumoctopus mimicus

The mimic octopus is a fascinating and unique creature that has gained worldwide attention for its incredible ability to change its appearance to mimic other animals. This fascinating creature, scientifically known as Thaumoctopus mimicus, certainly lives up to its name. Derived from the Greek word “thauma” meaning “marvelous”. This charming creature is truly a master of disguise. It can mimic the appearance and movements of other animals, such as sea snakes, flounder, stingrays, jawfish, snake eels, and even lionfish.

Octopus-Mimic

Marinefacts

The mimic octopus is found in the waters of the Indo-Pacific, where it employs its mimicry abilities as a survival strategy to elude potential predators and capture prey. Mimic octopuses use mimicry as a defensive mechanism, predominantly during feeding. These organisms engage in diurnal foraging activities within exposed sandy areas, rendering them susceptible to potential predation. This phenomenon could explain the prevalence of poisonous and venomous marine organisms in mimicry.

The mimic octopus is exceptionally intelligent, particularly to its predators. The octopus learns which animals annoy its predators and assumes their form to repel potential danger. When bothered by damselfish, for instance, the mimic octopus takes the form of a sea snake that preys on damselfish.

But the mimic octopus is not just a master of disguise. It is also a skilled escape artist. When threatened, it can use its flexible body to squeeze through tiny spaces and disappear into the safety of the surrounding coral reefs.

Couple-Octopus-Mating

The Challenges Mimic Octopus Face

While the mimic octopus is a master of disguise, it unfortunately faces threats from human activities such as overfishing and pollution. We must take action to preserve the natural habitat of this fantastic creature. The mimic octopus is a remarkable animal showcasing the astonishing diversity of life in our oceans. Its ability to mimic other animals is a testament to the adaptability and ingenuity of nature. We must do our part to protect this unique creature and the fragile ecosystems it calls home.

Thaumoctopus-Mimicus