Tag Archives: Cephalopods of Okinawa

The Paintpot Cuttlefish – Cephalopods in Okinawa

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The Paintpot cuttlefish (Metasepia tulbergi) is one of the most beautiful marine animals in Okinawa. The skin of the paintpot cuttlefish is toxic (poisonous) if consumed. The paintpot cuttlefish contains a neurotoxin called tetrodotoxin (venom) used to paralyze its prey. Avoid handling or harassing this beautiful animal. If bitten, seek immediate medical treatment.
  • Scientific name: Metasepia tulbergi
  • Common name:  Paintpot cuttlefish or flamboyant
  • Distribution:  Ryukyu Islands
  • Habitat:  Sandy bottom and coral reefs
  • Diet: Crabs, shrimp, and fish
  • Average size: 50-80mm
  • Color: Golden-yellow with red coloration
DSC_4989 Cool facts about the Paintpot Cuttlefish  
  1. They have eight arms and two tentacles
  2. They are capable of producing a dark cloud of ink to escape from predators
  3. They have a parrot-like beak used for eating prey
  4. They use jet propulsion to move quickly through the water
  5. They can change their texture, pattern, color, and shape
  6. They use their arms to walk on the sand
  7. They are considered venomous and poisonous
When threatened, the paintpot cuttlefish produces vibrant colors to warn predators that they are toxic. The scientific term for this is aposematism. DSC_8214 They have a two-part parrot-like beak used for feeding. Cephalopod Beak Cephalopods can produce a cloud of ink to confuse and escape from predators when threatened. Cephalopod ink Below is a sequence of images, displaying their ability to change texture, shape, and color. They are masters of camouflage. An example of how well they blend into their environment. DSC_8207DSC_8208If detected or threatened, they will display colorful warning signs. DSC_8209DSC_8211

Every year, I look forward to finding the gigantic paintpot cuttlefish named Paintpot-Zilla. 20130617-DSC_0519-2

My Mission: To Protect and Preserve the Wildlife of the Ryukyu Islands for Future Generations

If you would like to help me make a difference Please check out my Patreon Site https://www.patreon.com/MakeTheSwitch4Nature

Your donations will help conservation initiatives as well as bring solutions to the worldwide pollution issues on our beautiful shorelines.  Thank you for your support, Shawn M Miller.

#MakeTheSwitch4Nature

Masters of Evasion – The Bobtail Squid of Okinawa

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The spotty bobtail squid ( Eumandya parva ) is a small cephalopod found in the beautiful waters surrounding Okinawa. They are hard to find due to their small size. Persistence, patience, and diving with a buddy with good eyes will increase your chances of finding them.

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  • Scientific name: Eumandya parva
  • Common Name: Bobtail Squid
  • Found:  Ryukyu Islands
  • Habitat: Open water @ night
  • Average Size: 15mm – 25mm

Bobtail squid have eight arms and two tentacles used to capture prey. They have a two part parrot-like beak used for feeding. They primarily feed on small crustaceans free swimming in open water.

43057477232_9a230ddb9f_zWhat’s really impressive about cephalopods is that they are masters of evasion.  They are equipped with advanced mirroring cells. These cells can change shape and color to match their surrounding. These vibrant chromotophores are also used for communication and attracting a mate.

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The bobtail squid has the ability to produce a large ink cloud (smoke screen) when in danger. This cloud of ink will confuse predators and give the squid a chance to escape safely.

9055908826_9fd643b9e2_z 11545089173_d92e317cd9_zSquid have wing-like fins used for precision movement through the open water. Their siphon is used for jet propulsion, allowing a clean getaway from predators.
15231802761_420c562a03_z They can also evade predators by covering up with sand to avoid detection.

7047055933_2ab7599067_bI found this large Euprymna brenneri covering itself with sand to avoid detection. I have only seen two of these in the waters of Okinawa. A new species decribed in December 2019.

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Euprymna brenneri

Mating season occurs in the summer months. 

mating bobtail squidLook close and you can see the white bundle of spermatophores produced during the mating process. The eggs will be fertilized and attached to a safe location under a reef ledge. Tiny bobtail squid will hatch from their eggs in three weeks.

bobtail squid and eggsIf you would like to learn more about the Cephalopods of Okinawa, check out my previous posts on the blue-ringed octopus, pygmy squid, pharaoh cuttlefish and the shell eating octopuses of Okinawa.

My Mission: To Document and Preserve the Wildlife of the Ryukyu Islands

This site is also designed to help people identify the beautiful animals of Okinawa, basically to serve as an online nature reference guide. If you would like to make a contribution to support my mission, please click on the donation link  paypal.me/maketheswitch4nature

Your donations will help conservation initiatives as well as bring solutions to the worldwide pollution issues on our beautiful shorelines.  Thank you for your support, Shawn M Miller.

#MakeTheSwitch4Nature

Get Fa-Millerized with the Nature of the Ryukyu Islands  – – –  SUBSCRIBE BELOW

Ryukyuan Pygmy squids and hydroid-eating nudibranchs

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In the summer of 2018, I documented some exciting animal behavior underwater. While searching for the blue-ringed octopus in a shallow reef cut, I stumbled upon the elusive pygmy squid (Idiosepius sp). I first photographed the Ryukyuan pygmy squid back in 2012 and was excited to see another one. This undescribed pygmy squid is only 10mm-14mm in size. It can be difficult to get an acceptable photograph of it free-swimming through the water.

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Its amazing how fast squid can change color to blend into the sounding background. Look at that camouflage.

29545399098_f064fc3ef3_zThe pygmy squid has defined white nodules on the posterior end of the mantle used for attaching to seaweed and rocks.

Pygmy squid Okinawa

I took a few photographs of the tiny squid and it eventually retreated into fireweed (Aglaophenia cupressina).

DSC_0742The fireweed looks like a harmless piece of seaweed but its actually a dangerous stinging hydroid. The fireweed delivers a painful sting causing redness, irritation and infection.

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I returned to the exact location a few days later in search of the pygmy squid. I found the fireweed but it was much smaller, as if it was purposely cut down. These fireweed colonies have been in the same reef cut for over six years. What could have caused this devastation?  Was it possible that a Scuba Instructor cut down the fireweed colonies for the safety of their students? I mention this because the hydroids are in a high-traffic swim-through area, and some days literally hundreds of divers swim through this reef cut.

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My first thought was someone cut down the fireweed but I was wrong. It was actually a brightly colored nudibranch named Tenellia yamasui (Hamatani, 1993). The fireweed was infested with juvenile nudibranchs feeding on it.

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You would think that the nudibranchs would be conservative and keep some food for the future. The sea slugs devoured the entire fireweed.

Ever wonder what this stinging hydroid can do to your skin?  To learn more about the dangerous animals and treatments, check out my post on The Hazardous Marine Life of Okinawa.

Hydroid sting © Mark Kane

Hydroid sting © Mark Kane

Get Fa-Millerized with the Nature of the Ryukyu Islands  – – – –  SUBSCRIBE BELOW

Searching for Cephalopods by Shawn Miller

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Lately, I have been getting out a lot more on night dives. The conditions have been great for Scuba diving and underwater macro photography.  Diving at night is exciting because you never know what you will find. My last dive I stumbled upon a few new brightly colored nudibranchs and an undescribed pygmy cephalopod known as the pharaoh cuttlefish.

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Could this pygmy cuttlefish be an undescribed species or just a clever juvenile broadband cuttlefish resembling the sand?

  • Scientific name:  Sepia sp
  • Common Name: Pygmy or Pharaoh Cuttlefish
  • Found:  Kin bay, Okinawa
  • Habitat: Sand bottom @ night
  • Depth:  35feet 
  • Size:  17mm

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DSC_2082 DSC_2093 DSC_2104DSC_2111More than likely this pygmy cuttlefish is Sepiella inermis.  The pharaoh cuttlefish is absolutely stunning. I found this large specimen sand-dwelling during a night dive.

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If you have never been night diving I highly encourage you to try it. If you want to learn more about Cephalopods of Okinawa, check out my post on the beautiful Blue-ringed octopus. 

 My Mission: To Document and Preserve the Wildlife of the Ryukyu Islands

This site is also designed to help people identify the beautiful animals of Okinawa, basically to serve as an online nature reference guide. If you would like to make a contribution to support my mission, please click on the donation link  paypal.me/maketheswitch4nature

Your donations will help conservation initiatives as well as bring solutions to the worldwide pollution issues on our beautiful shorelines.  Thank you for your support, Shawn M Miller.

#MakeTheSwitch4Nature

Get Fa-Millerized with the Nature of the Ryukyu Islands  – – – –  SUBSCRIBE BELOW

Cowrie Shell Eating Octopuses of Okinawa

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In 2010, a friend sent me some beautiful cowrie shells from Hawaii. I noticed that a few specimens had tiny pin holes between the teeth on the underside of the cowrie shell.  I asked him what caused this and he stated an octopus. So I decided to test this, I collected a small octopus and placed it in aquarium with no other marine life in the tank. 5518026347_afbd22a0ed_b(1) I placed only live cowrie shells in the tank to see if this octopus would eat the mollusks.  I was completely surprised to find out that he was 100% correct. IMG_7293 IMG_7227The tiny drill holes are difficult to see without a magnifying glass. IMG_7232 Strangely, two of the cowrie shells had a drill hole on the top and another on the bottom side. The other eight specimens only had one drill hole on the bottom side. Is it possible that the octopus learned a new behavior?  Did it it figure out the most efficient way after the two previous attempts? FotoJetAll octopuses have a two-part beak used to immobilize and feed on their prey. The beak looks fragile but it one of the toughest and most durable substances made by marine animals.
Cephalopod Beak

Cephalopod Beak

My curiosity led me to the questions below Why does the octopus have to drill a hole when there is already a large aperture to feed from?  Does the octopus use venom to paralyze the mollusk inside the shell after it drills the hole? If so, does the venom narcotize the mollusk which could allow the octopus to suck out the animal from the shell aperture like a shotgunning effect? IMG_7296 Have you ever wondered how the Okinawans catch small octopuses?  Below is a colorful handmade lure made from cone shells and beads.  I found it years ago at Awase flats. IMG_7288 My Mission: To Protect and Preserve the Wildlife of the Ryukyu Islands for Future Generations

If you would like to help me make a difference Please check out my Patreon Site https://www.patreon.com/MakeTheSwitch4Nature

Your donations will help conservation initiatives as well as bring solutions to the worldwide pollution issues on our beautiful shorelines.  Thank you for your support, Shawn M Miller.

#MakeTheSwitch4Nature

Get Fa-Millerized with the Nature of the Ryukyu Islands  – – – –  SUBSCRIBE BELOW