Tuesday, October 07, 2025

Blackwater photos suggest new symbiosis between fish and anemones

Virginia Institute of Marine Science

Carangidae-Anemone_Linda Ianniello — image:
A juvenile carangidae appears to be holding an anemone in its mouth. Photo by Linda Ianniello.
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Credit: Linda Ianniello

A new manuscript in the Journal of Fish Biology reveals that relationships between fish and sea anemones are more diverse than those portrayed in Finding Nemo. Captured through breathtaking blackwater photography, the images featured in the article show rarely seen encounters between these creatures that may provide mutual benefits.

Gabriel Afonso, lead author and Ph.D. student at William & Mary’s Batten School of Coastal & Marine Sciences & VIMS, said that the emerging field of blackwater photography, or images captured by night-time divers, made this study possible.

Rich Collins is one of the divers who contributed to the article and a consultant at the Florida Museum of Natural History. He has witnessed lots of surprising interactions between tiny organisms since he started doing blackwater photography, such as filefish carrying box jellyfish in their mouths despite their dangerous sting.

“Some species of vulnerable larval or juvenile fish use invertebrate species apparently for defensive purposes,” Collins said. “They’ll find something that’s noxious or stingy, and they just carry it around.”

The pictures featured in the article show how this behavior extends to other juvenile fish and larval anemone interactions. Filefish, driftfish, pomfrets, and a young jack can be seen carrying larval tube anemone or button polyps in their mouths, possibly for protection.

While adult fish are known to cling to corals for rest and other purposes, the way these juveniles seem to be using anemones for self-defense is still not fully understood. While the sting from a larval anemone might not be enough to kill a predator, it would be “unpalatable,” Afonso said.

This could be a new form of mutualism between fish and anemone, because the anemone could also benefit from being carried by the fish as a form of dispersion.

“The anemones have a relatively low speed compared to juvenile fish,” Afonso said. “As far as I know, this is the first relationship of an open water fish interacting physically with an anemone that looks to be carrying the invertebrate.”

Afonso hopes that this article sheds more light on the previously unseen world revealed by blackwater photography and sparks people’s curiosity about the many different interactions happening between fish and invertebrates of all shapes and colors.

Visit the Wiley Online Library to read the full article.

Juvenile filefish carrying a palythoa larva in its mouth. Photo by Rich Collins.

Juvenile bamidae holding an anemone in its mouth. Photo by Linda Ianniello.

Journal

Journal of Fish Biology

DOI

10.1111/jfb.70214

Subject of Research

Animals

Article Title

Associations between fishes (Actinopterygii: Teleostei) and anthozoans (Anthozoa: Hexacorallia) in epipelagic waters based on in situ records

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Easter Island’s statues actually “walked” – and physics backs it up

New study uses 3D modeling, field experiments to confirm how Rapa Nui villagers moved massive statues

Binghamton University

Walking moai — image:
A research team including Binghamton University archaeologist Carl Lipo has confirmed via 3D modeling and field experiments that the ancient people of Rapa Nui "walked" the iconic moai statues.
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Credit: Carl Lipo

For years, researchers have puzzled over how the ancient people of Rapa Nui did the seemingly impossible and moved their iconic moai statues. Using a combination of physics, 3D modeling and on-the-ground experiments, a team including faculty at Binghamton University, State University of New York, has confirmed that the statues actually walked – with a little rope and remarkably few people.

Studying nearly 1,000 moai statues, Binghamton University Professor of Anthropology Carl Lipo and the University of Arizona’s Terry Hunt found that the people of Rapa Nui likely used rope and “walked” the giant statues in a zig-zag motion along carefully designed roads.

Lipo and his colleagues had previously demonstrated via experimental evidence that the large statues “walked” from their quarry to ceremonial platforms using an upright, rocking motion, challenging a theory that the statues were moved lying prone on wooden devices.

“Once you get it moving, it isn’t hard at all – people are pulling with one arm. It conserves energy, and it moves really quickly,” said Lipo. “The hard part is getting it rocking in the first place. The question is, if it's really large, what would it take? Are the things that we saw experimentally consistent with what we would expect from a physics perspective?”

To explore how a larger statue might move, Lipo’s team created high-resolution 3D models of the moai and identified distinctive design features – wide D-shaped bases and a forward lean – that would make them more likely to be moved in a rocking, zig-zagging motion.

Putting their theory to the test, the team built a 4.35-ton replica moai with the distinct ‘forward-lean’ design. With just 18 people, the team was able to transport the moai 100 meters in just 40 minutes, a marked improvement over previous vertical transport attempts.

“The physics makes sense,” said Lipo. “What we saw experimentally actually works. And as it gets bigger, it still works. All the attributes that we see about moving gigantic ones only get more and more consistent the bigger and bigger they get, because it becomes the only way you could move it.”

Adding to the support for this theory are the roads of Rapa Nui. Measuring 4.5 meters wide with a concave cross-section, the roads were ideal for stabilizing the statues as they moved forward.

“Every time they're moving a statue, it looks like they're making a road. The road is part of moving the statue,” said Lipo. “We actually see them overlapping each other, and many parallel versions of them. What they are probably doing is clearing a path, moving it, clearing another, clearing it further, and moving it right in certain sequences. So they're spending a lot of time on the road part.”

Lipo said that nothing else currently explains how the moai were moved. The challenge to anyone else is to prove them wrong.

“Find some evidence that shows it couldn't be walking. Because nothing we've seen anywhere disproves that,” said Lipo. “In fact, everything we ever see and ever thought of keeps strengthening the argument.”

Lipo said Rapa Nui is notorious for wild theories backed by zero evidence. This research is an example of putting a theory to the test.

“People have spun all kinds of tales about stuff that's plausible or possible in some way, but they never go about evaluating the evidence to show that, in fact, you can learn about the past and explain the record that you see in ways that are fully scientific,” said Lipo. “One of the steps is simply saying, "Look, we can build an answer here.”

Lipo said that the research also honors the people of Rapa Nui, who achieved a monumental engineering feat with limited resources.

“It shows that the Rapa Nui people were incredibly smart. They figured this out,” said Lipo. “They're doing it the way that's consistent with the resources they have. So it really gives honor to those people, saying, look at what they were able to achieve, and we have a lot to learn from them in these principles.”

The paper, “The Walking Moai Hypothesis: Archaeological Evidence, Experimental Validation, and Response to Critics,” was published in the Journal of Archaeological Science.

Statues walking [VIDEO]

Field experiments revealed that using rope and a small group of people, the people of Rapa Nui could have "walked" the moai statues.

This diagram illustrates the "walking" technique whereby moai were moved along prepared roads through alternating lateral rope pulls while maintaining a forward lean of 5–15° from vertical.

Example of a road moai that fell and was abandoned after an attempt to re-erect it by excavating under its base, leaving it partially buried at an angle.

Lipo's team created 3D models of moai to determine the unique characteristics that made them able to be "walked" across Rapa Nui.

Credit

Carl Lipo