Crinoid ecology on a deep, tropical island slope (2012-2014)

Deep-water tropical rocky seafloors are among the least studied habitats in the ocean. Karl Stanley’s three-person submersible, stationed on the island of Roatán off the coast of Honduras in the western Caribbean Sea, affords us a unique opportunity to visit, and re-visit, the same locations, and even the same individual marine creatures. Just a 20-minute surface run out of Half Moon Bay takes us beyond the shelf for a vertical drop into the depths. I am working on two main projects here with paleontologists Tom Baumiller (University of Michigan) and Forest Gahn (Brigham Young University, Idaho). Both focus on crinoids—the sea lilies and feather stars: “Ecology of the ‘Living Fossil’ Holopus rangii” (funded by NSU) and “Predation and its effects on the bathymetric distribution of crinoids" (funded by National Geographic). Crinoids have a vast and important fossil record. By investigating the living species, we hope to learn more about evolution and life in ancient seas. We are also collaborating with NOAA scientists to learn more about the distribution, ecology and growth of local deep-water corals and other organisms. An unexpected bonus was recently published in Messing CG, Stanley K, Reed JK, Gilmore RG (2013) The first in situ habitat observations and images of the Caribbean roughshark, Oxynotus caribbaeus Cervigón, 1961. Proceedings of the Biological Society of Washington 126(3):234–239.

In July 2013, Tom, Forest and I were accompanied by a production crew from WPBT-2 Public Broadcasting in Miami led by producer Alexa Elliott, who shot an episode of their long-running series "Changing Seas" that focused on our research. The episode, "Living Fossils", aired on WPBT-2 in June 2014 and can be viewed at http://video.wpbt2.org/video/2365255097/.

Tom and I returned to Roatán in May 2014 for our third expedition. Results from our first two trips on the strange barnacle-like crinoid, Holopus rangii, were recently presented at this year's North American Echinoderm Conference:

Syerson VJ, Messing CG, Baumiller TK (2014) First insights into growth and population dynamics in the extant cyrtocrinid Holopus rangii (Crinoidea). 7th NAEC, University of West Florida, Pensacola FL, 1-6 June 2014. Abstract #19, p. 32.

 

About to dive. Sean Hickey videotapes the launch for an episode of WPBT-2 Miami's "Our Changing Seas."

Pilot and owner Karl Stanley prepares one of the camera housings.

Paleontologist Tom Baumiller (University of Michigan).

Numerous Holopus rangii under an overhanging ledge at a depth of about 390 meters. The stump of a dead Holopus (center) and a few Cyathidium pourtalesi, its tiny dark relative, are also visible.

Living Holopus and numerous dead stumps. Examining their numbers, sizes and ages should tell us a great deal about how their populations change over time. The insert shows a closely related fossil species from just after the extinction of the dinosaurs. Photo: Karl  Stanley. Insert: Donovan SK, Jakobsen SL (2004).

Collecting a juvenile Holopus with the sub’s simple net.

Cenocrinus asterius is the largest Atlantic sea lily. Its stalk reaches almost a meter long and its crown almost 25 cm across. It is also the shallowest-living Atlantic sea lily; we found it off Roatán as shallow as 140 m.

A group of stalked Endoxocrinus parrae carolinae and three yellow feather stars, Crinometra brevipinna, on a glass sponge.

These superficially crinoid-like Novodinia antillensis are actually sea stars in the deep-water family Brisingidae.

The deep-water branching stony coral, Dendrophyllia alternata, accompanied by anemones and the squat lobster Eumunida picta (depth ~400 m). Colonies ranged from pure white through yellow to brown.

The squat lobster Eumunida picta feeding on a planktonic colonial sea squirt, Pyrosoma sp., while clinging to a yellow sea fan (Nicella sp.) and surrounded by snake stars (Asteroschema sp.).
 

Eight tentacles with fine side branches indicate that this polyp is a  solitary octocoral, a close relative of sea fans and other gorgonians, rather than sea anemones (which have tentacles in multiples of six).

Though it is a true bony fish, the strange Caribbean jellynose, Ijimaia antillarum (family Ateleopididae), has a skeleton composed mostly of cartilage.

The pink frogmouth, Chaunax pictus, a relative of the anglerfishes, can inflate its gill chambers to make itself appear much larger.

This photo, taken by pilot Karl Stanley in January 2013, is the first of a male Caribbean rough shark, Oxynotus caribbaeus, in its natural habitat. Karl has made more observations of this species than anyone else.