This month we would like to give the honors to our more elusive critters we see underwater here in the British Virgin Islands. We have done some research and came up with a few fun facts about each one of these! With elusive we mean they do exist as we have seen them here in the past 3 years, but it also means that some of them we have only seen once and some of them we might see a bit more frequent!
Some of our more frequent elusive critters and one of our favorites are Nudibranchs and Sea Slugs. We commonly see Lettuce Leaf Sea Slugs here but rarer are the Elysia Ornate another Sea Slug. These Sea Slugs generally like to hang out on rocks or coral heads especially in very shallow areas and they do seem to like the warmer water. Nudibranchs we find here are the Purple-Spotted Sea Goddess and also the black spotted Nudibranch. The word “Nudibranch” comes from the Latin nudus, naked, and the Greek brankhia, gills. They have the most beautiful bright colours, blend in very well and are hard to spot! The difference between these critters is hard to tell but you could say that Nudibranchs are all sea slugs, but not all sea slugs are Nudibranchs. There are several orders of sea slugs, of which the Nudibranchs are just one of between 1500 to 2000 species of sea slugs.
The Leopard flatworm is neither of them, but looks a lot like them. In general they are bigger and when we do spot them they are on the move. The Leopard flatworm has no true predator to watch out for. They feed on injured animals, dead animals and soft corals. The males reproductive system is based on their coloration and color pattern. There for, the female Leopard flatworm is more attracted to the male with the most and biggest spots. On average, flatworms have a 205 day life expectancy.
Another one of our elusive critters is the seahorse! In about 3 years time we have had only about 4 sightings, the most recent a week or 2 ago on Ginger Steps! Seahorse is the title given to forty-seven species of marine fish which they like to call Hippocampus. “Hippocampus” comes from the Ancient Greek with hippos meaning “horse” and kampos meaning “sea monster. According to Guinness World Records 2009, the dwarf seahorse is the slowest moving fish, with a top speed of about 5 feet (150 cm) per hour.
The Frog Fish is an even more elusive creature. We had one living on Little Grotto last year. After about 6 weeks he moved on though and we are still waiting for his return. Frogfish have a sort of angler hanging off their heads which they use to catch their prey and he can regenerate this angler if it gets lost or eaten. When threatened he can inflate like a puffer fish and normally he moves by walking across the sea bed.
Hammerhead sharks are another rare sighting, only one sighting by us to be honest! Last summer our crew spotted a 10 foot Great Hammerhead on the wreck of the Chikuzen. There are 9 different species of Hammerhead sharks. The Great Hammerhead is the largest of all and can grow up to 20 feet and weigh about 600 pounds. The smaller ones are about 13 feet. They live to be about 35 years and are very social, usually living in packs of 10 to 20. They can swim down to depths of more than 800 feet and can reach a speed of 25 miles/hr. Hammerheads look weird, they have a flat head, with eyes on the edges, which gives them a better visual range than most. They also spread their sensory organs over this wide head so they can more thoroughly scan the sea floor for food. Their favorite meal is stingrays.
Occasionally we get to see dolphins on the surface, jumping the wakes of the boat, or even underwater. Twice we encountered these beautiful creatures on our dive at the Rhone. Dolphins are believed to be one of the oldest mammals and they evolved some 60 million years ago. They can dive down deeper than 1000 ft and swim at a speed of up to 25 miles/hr. Being a mammal means that they need to come up for air every 20 seconds to every 30 minutes. When they sleep however, they can shut down parts of the brain, while the other part stays awake so they can keep on breathing. Dolphins are the only mammal that gives birth with the tail first instead of the baby’s head. The average lifespan is 17 years and each dolphin’s dorsal fin is unique, which is nice if you want to identify them! Dolphins have 100 teeth and they use these to swallow up to 30 pounds of fish each day! These fish will have to go through the two stomachs a dolphin has, just like cows!
More common are octopi, octopuses, and octopodes. These are the 3 plural forms of octopus and staying with that number, an octopus has 3 hearts, two to pump blood to each lung and the third to pump blood throughout the body. Octopi can live anywhere from six months to five years. Because they have no bones they can squeeze into the tiniest holes and crevices. These creatures are very smart and are known to be able to solve puzzles and they also have arms, not tentacles. Tentacles are longer than arms and they usually have suckers only at their tips.
There are a lot more interesting creatures out there but I am only writing a blog, not a book! I wish I could go on and on about whales, peacock flounders, squid, scorpion fish and all the other amazing marine life we see out here! I hope I have awoken your interest though and you should definitely come and visit us in the British Virgin Islands, so you can see it for yourself!