Marine Life & Conservation Blogs
The blue-ringed octopus: a beautiful but dangerous creature (Watch Video)
The third in an exciting new series of blogs introducing some of the amazing marine life you can encounter at Magic Resorts in the Philippines…
One of the most popular octopuses that’s high on almost every divers’ bucket lists, is the blue-ringed octopus. The aptly named creature gets its name from the blue rings on its skin. These creatures usually turn out smaller than everyone’s expectations, but don’t underestimate the power of these critters!
Did you know that the blue-ringed octopus is actually one of the most venomous animals in the world? You definitely don’t want to make this creature angry. So how do you know that you have gone too far and annoyed the octopus? This creature will warn you! Usually a dark brown to yellow color with blue patches or rings, it will turn darker and the blue rings will become brighter and brighter! Though usually shy in nature, if they are stepped on or angered, they will bite!
This little octopus produces two types of venom – one for protection and one for hunting. The one for protection is produced by bacteria that live in its salivary glands. The tetrodotoxin it produces is the same deadly toxin that pufferfishes have. Experiments show that one single blue-ringed octopus has enough venom to fatally paralyze 26 adult humans… at the same time! Unfortunately, there is no antivenom yet and treatment requirements include life-support machines such as artificial ventilation.
There is not just one type of blue-ringed octopus though, there are at least 10 different species which can be found in tidal pools and reefs in the Indo-Pacific Ocean.
During the night, these little octopuses will search for food. They tend to hunt for crabs, clams, shrimps, small fish, etc. But they also have to be wary of their predators, mainly eels.
Fun fact: when a blue-ringed octopus loses a tentacle, it will grow back automatically!
Come and dive at Magic Oceans and let the guides show you these docile blue-ringed octopuses in Anda, Bohol. The guides will help you capture that perfect picture, and you can witness how the little octopus goes about its daily life.
Some general facts!
- Blue-ringed octopuses can have up to 50 – 60 blue rings on their skin.
- They are roughly 5 – 8 inches in size.
- The bite of a blue-ringed octopus is usually reported as painless
- They tend to have a life expectancy of up to 2 years and lay 50-100 eggs when they mate.
Visit Magic Oceans Anda, Bohol and Magic Island Moalboal, Cebu… find out more at www.magicresorts.online.
In this series, the Shark Trust will be sharing amazing facts about different species of sharks and what you can do to help protect them.
As we’re currently in butterfly season, this month we decided to concentrate on the Butterfly Rays!
Within the family Gymnuridae, there are two genera and 12 species of Butterfly Ray. These species are morphologically different to lots of other rays because of the width of the disc and pectoral fins – in contrast to many other species of Butterfly Ray, their bodies are much wider than they are long, especially considering their very short tail. This gives them the appearance of gliding or flying across the sand.
Gymnura altavela – Spiny Butterfly Ray
Gymnura australis – Australian Butterfly Ray
Gymnura crebripunctata – Longsnout Butterfly Ray
Gymnura japonica – Japanese Butterfly Ray
Gymnura lessae – Lessa’s Butterfly Ray
Gymnura marmorata – California Butterfly Ray
Gymnura micrura – Smooth Butterfly Ray
Gymnura natalensis – Backwater Butterfly Ray
Gymnura peocilura – Longtail Butterfly Ray
Gymnura sereti – Seret’s Butterfly Ray
Gymnura tentaculata – Tentacled Butterfly Ray
Gymnura zonura – Zonetail Butterfly Ray
Spiny Butterfly Ray, Gymnura altavela. Playa La Granadella, Spain, Mediterranean Sea.
Today we’re taking a look at Gymnura altavela, the Spiny Butterfly Ray. Like all Butterfly Rays, the Spiny Butterfly Ray is a demersal species, meaning it spends the majority of its time on the bottom of the seabed. Butterfly Rays are known for their burying behaviour in the sand, a technique they use to camouflage themselves when they are resting during the day. This protects them from predators, in some areas larger sharks. It also aids them in their ambush hunting technique – by hiding themselves under the sand they are able to easily snatch up their dinner – usually crustaceans, molluscs or other small fish – as they swim by unawares. This behaviour can leave tell-tale butterfly-ray shaped imprints in the bottom of the seabed.
Spiny Butterfly Rays can grow up to 260 cm (disc width (wingspan)), although average is around 200 cm. They give birth to live young, and each litter consists of 1-8 pups. This species has also been found to aggregate, likely for mating. One study found that aggregations of primarily females in the coastal regions off Gran Canaria may correlate with the shifting water temperature.
It is estimated that the species has undergone a population reduction of 50-79% over the last 33 years. This is primarily due to fishing pressure – the Spiny Butterfly Ray is targeted and bycaught in both industrial and artisanal fisheries types using a variety of gear types. The species is now Critically Endangered in the Mediterranean and Southwest Atlantic.
Scientific Name: Gymnura altavela
Family: Gymnuridae
Maximum Size: 260 cm (disc width)
Diet: crabs, shrimps, various invertebrates, fishes, small crustaceans, and molluscs.
Distribution: throughout the Atlantic and Mediterranean and Black Seas.
Habitat: muddy and sandy substrates down to 150m.
Conservation status: Critically Endangered in the Mediterranean and Europe, Endangered Globally.
For more great shark information and conservation visit the Shark Trust Website
Banner Image: ©Tomas Willems. Main image: ©Andy Murch
Voted No. 3 on the Top 10 Ultimate British Isles Bucket List by The Independent, these dives offer the closest marine mammal encounter available to divers in the UK. Friendly and playful, respectful divers are often rewarded by incredible interaction with the Lundy Seals.
Easy Divers has been running guided dive trips to Lundy for nearly 10 years and offers dive equipment hire if required. Trips depart from the stunning harbour town of Ilfracombe in North Devon and Dolphins are often seen during the boat passage.
In addition to diving, Ilfracombe is a great base from which to hike the South West Coast Path, dip into surfing at the UK’s first World Surf reserve, enjoy other water sports or head to Exmoor National Park.
Easy Divers also runs a diver-friendly guest house, with a discount for diving customers and kit rinsing and drying facilities.
The Seal encounter dive sites are shallow and sheltered and are suitable for divers of all levels, making them a great introduction to British diving.
Exclusive Offer for Scubaverse Subscribers
Use your exclusive Scubaverse discount code scubaverse10% before the end of June and join us for a Seal encounter dive trip to Lundy Island, on any trip date with availability this Summer. Visit https://www.easydiversnorthdevon.co.uk/lundy-dive-trips/seal-encounter-dive-trips/ and enter code scubaverse10% at the on-line check out.
Trips book out well ahead, so book now to avoid disappointment. To save 10% on any 1 night stay at our guest house, please call 07833 020424. We offer free cancellation for divers who book a 1 night stay, if we have to re-schedule due to unsafe weather.
Join us for Britain’s best marine mammal diving experience!
Trips run from end of May to mid-October and are bookable via email at info@easydiversnorthdevon.co.uk, on-line via the Easy Divers website, www.easydiversnorthdevon.co.uk, or call 07833 020424 for more info
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