The ocean is home to countless fascinating creatures, but the nudibranch stands out for its stunning beauty. With vibrant colors and intricate patterns, these bright sea slugs are often called the ‘Butterflies of the Sea’.
Spotting nudibranchs during your dive would certainly make the journey more memorable,due to their beauty and how hard it is to find them. In this article, we’ll guide you through everything you need to know about nudibranchs, including where to find them and how to spot them in the wild.
What are Nudibranchs?
Nudibranchs are soft-bodied, marine invertebrate gastropod mollusks belonging to the class Gastropoda and the subclass Heterobranchia. Their bodies are adorned in unique colors and patterns, which make them a favorite among many divers, particularly underwater photographers.
The term ‘nudibranch’ itself means ‘naked gills’, which comes from the exposed gill structures on their back, which help these creatures breathe.
They can be found in many parts of the world, particularly in the Indo-Pacific region, including the Coral Triangle—a remarkable marine area with high biodiversity that comprises Indonesia, the Philippines, Malaysia, Papua New Guinea, Solomon Islands, and East Timor. To date, there are around 3,000 known species of nudibranchs.
In addition, nudibranchs are hermaphrodites and carnivorous. Their food source typically consists of sponges, hydroids, and even other members of their own species. They also have unique defense mechanisms such as camouflage, toxic chemicals, or stealing stinging cells from their prey.
Are Nudibranchs and Sea Slugs the Same?
Though nudibranchs are commonly known as sea slugs, they are not exactly the same. All nudibranchs are sea slugs, but not all sea slugs are nudibranchs. The term ‘sea slugs’ is a broad category consisting of various soft-bodied, marine gastropods, including sea hares, headshield slugs, and sacoglossans. On the other hand, nudibranchs belong to a specific subclass called Nudibranchia, which is identified by the naked gills on their backs and lack of a shell in adulthood.
What Are the Best Dive Spots to See Nudibranchs?
1. Anilao, the Philippines
Anilao, a stunning region in the Philippines, is one of the best places in the world to find nudibranchs. In fact, this region is called the ‘Nudibranch Capital of the World’. Home to a marvelous diversity of species, over 600 nudibranch species are found here.
Some examples are the elusive Hypselodoris apolegma, a droid nudibranch with a beautiful purple color that earned them the nickname ‘Bubblegum Worm’, and the rare and highly photogenic solar-powered nudibranch (Phyllodesmium longicirrum), which, unlike other nudibranchs, contains photosynthetic zooxanthellae, giving it the unique ability to draw energy from sunlight.
2. Milne Bay, Papua New Guinea
As a part of the Coral Triangle, Papua New Guinea’s Milne Bay is renowned for its marvelous marine biodiversity and pristine underwater ecosystems. The bay’s nutrient-rich waters and remote location make it a perfect habitat for many species of nudibranchs, as you can find them hidden between the coral bommies and sloping reefs.
If you’re lucky, you can also spot the rare dusky slug (Nembrotha kubaryana) and Loch’s chromodoris (Chromodoris lochi), a nudibranch commonly found in the region that’s known for its striking blue color.
3. Lembeh Strait, Indonesia
Known as the “Muck Diving Capital of the World”, Indonesia’s Lembeh Strait is a region that boasts a rich diversity of nudibranchs. The combination of sandy seabed, volcanic black sand, and scattered coral rubble in the area creates the perfect environment for these sea slugs to thrive.
In fact, Lembeh Strait is home to the rare ghost nudi (Melibe colemani) and Marionia blainvillea, two elusive nudibranch species that are hard to find anywhere else.
4. Cozumel, Mexico
Located off the Yucatan Peninsula, Cozumel is a destination that offers an underwater world with unparalleled beauty, particularly for macro divers. You can find an impressive variety of nudibranch species in this region.
Some examples are the purplering flabellina (Flabellina marcusorum), which attracts divers with its unique, purple-colored rings, and the rare purple-crowned sea goddess nudibranch (Felimare kempfi).
5. Palau, Micronesia
With a rich marine biodiversity and crystal-clear waters, Palau can offer you the best diving experience, particularly if you’re looking to find some beautiful nudibranchs.
Located in the western Pacific Ocean, this island country is renowned for its Blue Corner and German Channel, world-class dive destinations home to a wide range of macro critters, such as the fascinating blue dragon nudibranch and more.
6. Maui, Hawaii
Many nudibranchs can typically be found on various islands in Hawaii, but Maui is one of the best spots. Maui’s unique marine environment offers rewarding experiences for many divers and you can find many of them in its volcanic reefs, lava tubes, or underwater arches.
In fact, Maui also has a rare, endemic nudibranch called the gold-lace nudibranch (Halgerda terramtuentis), which can only be found around the region’s islands.
7. The Great Barrier Reef, Australia
As the world’s largest coral reef system, the Great Barrier Reef is home to a great variety of marine life, including reefs, sponge fields, and seagrass beds, which provide a habitat for these colorful sea slugs to thrive.
Some species you can commonly spot in the area include the rare Bornella anguilla, which is known for its brightly mosaic-like patterns, and the dorid nudibranch Loch’s chromodoris. The GBR also provides the opportunity to spot the rare short-tailed ceratosoma (Ceratosoma brevicaudatum), which is known for its bright colors.
Underwater Photography Tips for Nudibranchs
1. Know How to Spot Them in the Wild
The first thing you must prepare before photographing a nudibranch is knowing how to spot them in the wild. Looking for nudibranchs can be a challenge because of their small size and some of them can blend seamlessly with their surroundings.
To spot these critters, you’re going to need a keen eye and patience. Look closely at coral reefs, sponges, anemones, and rocky outcrops where nudibranchs live, feed, and hide. Focus on finding intricate textures and vibrant colors, as these details can help you identify them.
2. Choose the Right Gear
To get the best shots, you’ll want to make sure that you bring the right gear. This includes a DSLR or mirrorless camera. A 60mm lens is generally optional, but you should also bring a 100 or 105mm macro lens. In addition, you’re also recommended to bring a good focus light, such as a 500 lumens LED light or a strobe light that has a wide beam.
3. Get Close and Low
Nudibranchs are tiny, so try to get as close as your lens allows to fill the frame and shoot from the same level as the nudibranch for a more dynamic composition. However, don’t forget to be mindful of your position and buoyancy to avoid disturbing or damaging the delicate marine environment.
4. Focus on the Details
Aim to capture the rhinophores or the horn-like structures on their head. The rhinophores are often the most visually striking feature of a nudibranch. You can also experiment with manual focus for extra precision, especially when you’re photographing them from a close range.
5. Experiment with Angles
You can also try different angles, like top-down, side profiles or head-on shots to create more visually appealing compositions. Don’t hesitate to try experimenting with lighting angles to highlight different textures and shadows.
Discover Unique Marine Species with Solitude World!
Ready to spot these vibrant sea slugs and other unique species? Come dive with Solitude World’s Liveaboard and Resorts!
Our liveaboards can take you on an exciting dive journey in some of the best dive destinations in the world, which are Indonesia, the Philippines, and Palau. The liveaboards come with PADI-certified guides to ensure you have a smooth and memorable journey, as well as comfortable rooms where you can rest and recuperate after your diving journey.
In addition, our Solitude Acacia and Lembeh Resorts, which are located in Anilao (the Philippines) and Lembeh (Indonesia), provide a strategic base to dive in some of the world’s best macro diving sites. Our resorts also provide underwater photography workshops led by experts, as well as dedicated camera rooms for your equipment.
What are you waiting for? Book your stay at Solitude Liveaboards and Resorts today!