Parasitic slugs of Okinawa

Gymnodoris nigricolor Is a tiny nudibranch that attaches to the fins of gobies. It is found in the winter months and then it seems to completely disappear when the water warms up. This nudibranch is by far the hardest to photograph because of its size and it stays attached to it’s host. When the goby feels threatened, it retreats into its burrow taking the tiny slug down the hole with it.

In order to photograph sand-dwelling gobies you will generally need a 50mm-100mm macro lens.

IMG_0512Be patience and move slowly. If your lucky the goby will accept your presence without retreating.

IMG_0540February 2018, I was fortunate to find Gymnodoris nigricolor crawling on the sand in search of a host

IMG_0412When the slug finds a host it will attach onto the closest fin.

IMG_0423Look close and you can see the buccal apparatus of the slug clamping down.

27429475356_4380fdabcb_bOnce its locked down, the goby cannot shake the slug off.

14474545362_6904d1dc25_b(1) No one really knows what happens next. Why does the nudibranch attach to the fins of its host Does this specialist feed on only the fins of gobies or is there another reason

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If you would like see stunning photographs of more sea slugs check out my post on nudibranchs

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

Moai Statue Found Underwater, Okinawa-Japan

A  friend and I stumbled upon a Moai statue underwater. The statue had a good amount of surface growth on it as if it been underwater for a long time.  Is It possible Typhoon Trami uncovered this statue? or did someone place it there on purpose for an underwater treasure hunt?  Typhoon Trami was devastating and destroyed the coral and killed a good amount of marine life.

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Moai statue- Ryukyu Islands

Regardless if the underwater statue is authentic or not, I was excited when I found it. I have never seen anything like this underwater.  I got the same feeling when I went to Yonaguni to see the underwater monument.

  • Moai replica statue size: Two feet in length
  • Dive spot: Kadena north steps
  • Location: Okinawa, Japan.
  • Depth: Forty-five feet
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Moai statue- Ryukyu Islands

Recent update: The mystery has been solved. It was purposely placed there by a dive instructor for a treasure hunt! The statue is not authentic but still a cool find.

I was not well prepared to photograph a subject of this size. The plan was to photograph tiny nudibranchs and gastropods. I had my underwater rig setup with a designated 60mm macro lens.

Underwater Equipment used:

  • Nikon D500 +Nikon AF-S 60mm macro lens
  • Nauticam Na-D500
  • Light & Motion Sola 3800
  • Sea & Sea YS-D2 strobes

Please do not use any images without my permission. Know your nature with Shawn Miller, have a great day!

Gall Crabs – Coral-Inhabiting Micro Crabs of Okinawa

Gall crabs are coral-dwelling crabs that spend their entire life living inside a hole of the hard coral. These micro crabs are only 7mm-10mm in size.  They are hard to find and photograph due to their small size.

Gall crab in coral

Gall crab in Favia Coral © Shawn Miller

These tiny crabs are considered to be safe keepers or guardians of the hard coral. The gall crabs defend against coral eating predators such as starfish and snails. The coral provides shelter and food, making it an ideal habitat for the micro coral-dwelling gall crab. I have found these crabs in a variety of coral species in Okinawa. They are usually found in shallow water corals, but recently I found a healthy colony of crabs at sixty-five feet.

Gall crab, Maeda point

Gall crab claws out © Shawn Miller

Large algae covered gall crab

Large algae covered gall crab © Shawn Miller

Gall crab closeup  by Shaw Miller

Gall crab closeup © Shawn Miller

If you’re lucky you might see a gall crab searching for food during the night.

Unidentified gall crab

Unidentified gall crab © Shawn Miller

Gall crab searching for food

Gall crab searching for food © Shawn Miller

Unidentified gall crab © Shawn Miller

Unidentified gall crab © Shawn Miller

The only reason I found this beauty was because she was leaving the gall to release her eggs.

DSC_6209Some of the gall crabs fluoresce using the specialized Light & Motion Nightsea underwater blue light.

Gall crab fluorescence

After the crabs die, the galls become a new shelter opportunity for snails, fish, and reef crabs.

Prime Coral real estate

Prime Coral real estate © Shawn Miller

Bicolor blenny in coral - fish of okinawa

Bicolor blenny in coral © Shawn Miller

Yaeyama blenny

Yaeyama blenny © Shawn Miller

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Blenny in coral gall © Shawn Miller

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Blenny in coral gall © Shawn Miller

I found this hard coral washed up on Iheya Island. Look close and you can see that hole made by the gall crab.

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Stony coral and gall

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