Articles Comments

Marine Life Blog » Indonesia, Lembeh » Inspecting Anemone Hermits, beautiful Thorny Seahorses and a night dive grump fest

Inspecting Anemone Hermits, beautiful Thorny Seahorses and a night dive grump fest

March 24-25 – This morning we made the twenty-minute boat ride to one of the distant dive sites, California Dreaming, named by Scuba Diver Australasia’s editor, David Espinosa, years ago when he was diving the Strait with his mentor, legendary critter hunter, Larry Smith.The towering underwater precipice festooned with a multihued gallery of both hard and soft corals, provides a stunning visual contrast to the local muck sites. We went in search of Convict Fish and did find a large swarm of the 3/4-inch juveniles, but failed to locate their den, the permanent home to one or two brawny ten-inch adults. Ned, long ago bored with my latest fish mania, joined Liberty turning over rocks in a rubble field at the base of a cliff. Their patient search paid off big when Liberty uncovered a pair of tiny Harlequin Shrimp, Hymenocera elegans, busily consuming a tiny sea star that they had previously dragged to their lair. To inhibit the five-legged echinoderm’s escape Harlequin Shrimp will flip their prey on its back, and over a matter of days consume their stash, one leg at a time.

Harlequin turning sea star

Harlequin turning sea star

 Four years ago while videotaping a fist-sized Anemone Hermit Crab, Dardanus pedunculatus on a night dive at Jahir, I happened to spot a porcelain crab nestled next to base of one of the anemones attached to the crab’s protective shell. This particular species of hermit received its common name from its clever habit of severing anemones from rocks and attaching the wispy animals to their mobile homes. In theory this symbiotic relationship offers a semblance of protection for the crab while providing the anemones with mobility, which allows enhanced access to food. This example of symbiosis upon symbiosis instantly struck my fancy so I set about learning what I could about the relationship.  Now bear in mind that “close inspection” of a large, highly mobile hermit crab armed with nutcracker-sized claws isn’t exactly an easy task. However my curiosity as to whether this was a one-time occurrence or a regular behavior set me to task inspecting every Anemone Hermit I have encountered over the past four years. I have discovered in Lembeh that about half of the Anemone Hermits have one or more porcelain crabs riding hiding among their anemones. I decided to make it my mission to capture video that clearly shows the porcelain crabs. I first had to convince Ned and Liberty to help me with the project. Liberty attempted to hold a hermit in place by grasping the end of its shell and immediately received a rather nasty pinch for his efforts, so that wouldn’t work. Besides, when disturbed the anemones expel pink stinging threads and close up completely and the porcelain crabs scurry for cover inside the hermit’s shell. In the end, after Ned and Liberty became thoroughly disillusioned with the entire idea, I decided patience and a lot of chasing was the only solution. Here is video of one particularly large, half inch orange porcelain crab (large is relative, of course) riding on the hermit’s back. 

There is also a porcelain crab that lives with anemones on hermit crabs in the Caribbean, but I have not seen this association anywhere else in the Pacific, so this might just be another Lembeh Strait curiosity. Incidentally, last night I watched a huge mud crab feeding on an Anemone Hermit Crab. The anemone’s stinging threads, which fluttered in the mild current, offered no protection against the marauder’s tough exoskeleton.

 

Bus Sign

Bus Sign

A large group of business people stopped in for a luncheon at the resort. I ran out to take a photo of their buses, which were painted to advertise the upcoming World Oceans Conference. This provided an opening to talk to some of the group and I had a nice conversation with several gentlemen from the Development Bank. I am sending NOAA some underwater video that I hope they will be able to use in their Coral Triangle Initiative participation at the conference.

Thorny seahorse

Thorny seahorse

Our Wednesday morning dive was at Magic Crack, where Ned shot two beautiful Thorny Seahorses. I spent my dive with a shoal of baby squid floating around the mooring buoy line, which just happened to be the same buoy where, last year, I taped a group of adults laying finger-sized translucent egg cases.

 

We deemed our night dive the “grump fest” after Ned photographed two rather unhappy looking subjects.
Devilface

Devilface

Crab

Crab

We have three more days of diving here before we meet up with Paul and the rest of our group to travel on to Raja Ampat.~ Anna DeLoach 

Filed under: Indonesia, Lembeh · Tags: ,

Leave a Reply

*