Tonna perdix eating Stichopus sp.

Not many animals are known to eat sea cucumbers. There is a good reason. Most of them have chemicals in their body, which probably doesn't taste too good but more importantly may intoxicate the potential predators.

Humans have found a way to deal with these toxins. In the preparation of the bêche-de-mer, sea cucumbers are boiled for a long time which breaks down these chemicals.

If toxicity is a good way to avoid generalist predators, other animals have evolved to become specialists and can deal with the cocktail of toxins found in the skin and organs of sea cucumbers. In coral reefs, among the specialist predators, Tonna perdix is known to feed regularly on sea cucumbers, and in particular, on the species of the genus Stichopus.

After finding a Tonna perdix during a reef walk on Heron Island, I decided to keep it in a tank hoping to observe its feeding behavior. A few days later, Rob brought me back some Stichopus (that I can't identify to the species level) and decided to put it in the tank with the Tonna perdix. Before the Stichopus even touched the bottom of the tank, the Tonna perdix became really active. After a few minutes crawling around the tank, Tonna perdix used its proboscis to detach its prey from the wall of the tank, and in just a few seconds, the gastropod extended its proboscis around the sea cucumber swallowing it whole. Holly Heiniger had her camera with her to record this.

Sea cucumbers have also evolved ways to escape predation. In particular, Stichopus can shed its body wall to only leave pieces of it to the predator. However, in this case, the attack was so fast that the sea cucumber didn't seem to have any time to escape.

Packing up, moving on...

Rob has a distinctive packing style

Our three weeks in Australia have ended, so we are packing up all of the specimens, and shipping them back to the Florida Museum of Natural History.

Packing, itself, is a long drawn out affair- all the containters need to be drained of Ethanol, then packaged together with other specimens, heatsealed into a plastic bag, and then packaged into small barrels. With over 2000 specimens, it takes HOURS. But if it means that they make it back to the museum safely, it is time well spent.

The trip was interesting in terms of what was on the island, and what wasn't. As expected, rarity was the rule, and some groups that we expected to be common were all but absent. Unlike many places in the Indo-Pacific, the coral genus Pocillopora was largely absent from the area- and certainly not a reef dominant group, as it is in Moorea. The same could be said of many types of Sea Cucumbers. Parasitism of echinoderms and crustaceans was common.

The large scale questions remain: What drives these patterns of diversity? Why is this place different from others?

-Seabird

Dis-ARMS-ing

For the last few years our lab has been involved in putting ARMS on reefs. These are Autonomous Reef Monitoring Structures. The idea was to come up with a standardized unit to measure reef biodiversity. Each unit consists of PVC plates, spacers, and some wire mesh. The whole thing is anchored to the reef, and left to sit and get settled for a full year.

With Creefs back at Heron island for another season of biodiversity surveying, it was time to pull out the ARMS that had been placed last year. The video is of Shawn removing an ARMS from the bottom, and carefully boxing it and carrying it to the surface.

Taking them apart and sampling them fully is time intensive- and quite a few of the species we have gotten so far have not come from any other method of sampling, including the "Muppet Crab" featured at the bottom of the post.

-Seabird

The ARMS is carefully released from it's box....

The layers are unbolted

The mesh layer is on top.

Then several PVC layers

Everything is brushed carefully and all obvious creatures and plants are removed.

Everything is carefully rinsed and the rinse-water strained for small organisms

And then the specimens are carefully sorted to species in the lab.

And the treasures appear!

Large Octopus

There is no doubt about it. Octopus are amazing creatures. We encountered a large one on the reef the other day and I got a short video of it. Unlike most I've encountered it was not terribly shy, and stayed in view for more than a half hour. At about 5 feet across, size may have had something to do with it. The video gives a good sense as to how rapidly they can change color and texture to match the surrounding environment, or to send a signal. What it doesn't portray as well is the amount of -for lack of better words- personality that these animals have.

Enjoy. I sure did.

-Seabird

Farming on the reef

There are a few animals that farm. Humans, and ants on land, but what about the oceans? Jada-Simone White (http://www.flmnh.ufl.edu/malacology/white.htm) has been studying the details of one marine farming relationship- that of the "farmerfish" Stegastes nigricans (a type of damselfish) which actively cultivates an algal "turf farm".

Yesterday I had the opportunity to observe another type of marine farm. Throughout the Pacific Ocean, you can often see odd, short crevasses in large heads of coral. Sometimes they appear to have been carved in- like Petroglyphs.

These burrows are made by an Alpheid shrimp. If you look carefully, you can see that the edges of the burrow are lined with a hydroid, while the walls of the crevasse are covered in an algae, carefully cultivated by the shrimp from holes at the bottom.

The shrimp in this group typically have rather short limbs. In this case though, the secondary chela is very, very long and flexible, to be able to tend to the garden from the saftey of it's holes.

Most of the time you can't see how this works very well, but yesterday, I found a garden that was exposed on one side. I'm posting a video below, along with a little map. The two pink arrows are the first and last access points the shrimp has to its garden. The green arrow is the hole to watch in the video. Starting around 12 seconds into the vid, you can see an arm flash out of the hole, grab some algae, and be retracted. Pretty neat for a shrimp!

-Seabird

First Impression = heavily parasitized

First impressions of the Southern Great Barrier Reef: Diversity is high, with a few species familiar to us from Polynesia, but most are new. Decapod abundance seems lower in comparison, but that could just be the microhabitats that we dove on yesterday. One thing does appear to occur in serious abundance: parasitism. In the samples from Biocode on Moorea, it is an unusual occurance for us to encounter a parasite on a crustacean or seastar- perhaps one in one hundred. Here in Australia the rate seems much much higher- perhaps one in five.

Here is an externally parasitic snail, Thyca, on the seastar Lincka multiflora

And here is an internally parasitic snail, Stylifer, on the same species of seastar.

Understanding the pattern behind these differences is the trick. Part of it may be that diversity begets diversity, creating what Phillipe Bouche has called "the russian dolls of biodiversity." This is where one organism may have a commensal organism living with it, that commensal may have a parasite, and that parasite may have a parasite. We certainly see it with coral, where one species of coral may host many symbionts and each of these may have their own set of commensals and parasites. By increasing the number of species of structural species (corals in this case, but could just as easily be trees in a rainforest) by one, we increase the over-all diversity by many.

This Pink Coral Guard Crab (Trapezia serenei) is a good example. It lives exclusively in one family of corals. If you look at the carapace, you can see that it is asymetrical. In this case that is indicative of a Boporid- a crustacean parasite on crustaceans that has infected the crab.

-Seabird

Creefs- Heron Island Australia

Part of the team has just landed on Heron Island on the Southern Great Barrier Reef in Australia. After a rather "lumpy" two hour ride on the catamaran out to the island, we've started to settle in for a few weeks.

The island is absolutely alive with birds. During the day, noddies, egrets, rails, and plovers go about their business with cacaphonous ablomb. Now that the sun is setting, the shearwaters are arriving in droves, crash landing into people and buildings, then running to their nests in burrows in the sandy soil. It is new and amazing, though I am told that after a few weeks, you relish the comparative silence to be found underwater.

Our first dive will be tomorrow, so tonight we are setting up our equipment. We are here as part of the CReefs program to explore and document tropical marine biodiversity. As with Biocode, the efforts revolve around bringing in taxonomic and systematic experts to quantify as many taxa as possible during the short time we have here. FLMNH is represented by three people: Francois Michonneau, an expert in Holothurians, Rob Lasley who works on crabs, and myself, working on coral symbionts.