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Monday, 18 December 2017

The Lowly Worm

cirratulus cirratus worm
When we saw this long orange multi-corded piece of plastic on the dive at Bahia Tom, I was quite disappointed in seeing such a thing, and Larry took 2 photos of it! I listed it under 'plastic 00 and 01' on my Excel spreadsheet.
It has taken me several weeks of studying the Marine Benthic Fauna book (Haussermann & Forsterra) to discover that I was wrong about the Orange Plastic which we photographed on November 13. It's actually a WORM - a polychaete worm called 'cirratulus cirratus' - the angel hair worm. Reading more about it, I find it has multiple black eyes, with 8 rows ranged diagonally on each side. Our photographs are very high-quality, but I still cannot find any tiny black dots on this worm and I doubt  anyone else can find them in the photo. THIS is why you need a degree in biology and a microscope to be more than an amateur at marine identification.

We've now finished our seventeenth dive here in Chile - the dives have been very productive - Larry took 108 photos of our dive at 'Pozo Delfin'. I've edited all the photos and we've printed out our favoured species for our dive logs. I've generally identified them. The next step is to try to get a more specific identification using the Marine Benthic Fauna book' and they will then be massaged into a text file and organized in Excel after which comparisons can start as to what we've seen. We've done three dives at Pozo Delfin - one in 2007 and two in 2017.
There's a big learning curve to identifying the animals. Since many of the animals fit into the same niches as species we know from the Pacific NW, we know which class to fit them into on our Linnaeun species list. However, even with an I.D. book at hand, I'm not sure about many animals. Especially sponges and ascidians seem to resist easy classification. The Benthic Guide recognizes this, and the authors on each of the species provide the names of animals which could easily be mistaken for each other. As with many other subjects one can study, becoming familiar with the subjects takes a lot of concentrated study and experience.

Even within the world of scientists, changes are occurring with perplexing frequency. It's really hard for an amateur to keep up. I was astounded to learn that an animal we know as a nudibranch - the 'dendronotus rufus' - red dendronotid had appeared in a classic role in 'Pacific Coast Pelagic Invertebrates' which I simplistically imagined was all about jellyfish. It was very easy for me to mistake a hydrozoan (page 317) for the ascidian (p 895) in Benthic Fauna. Among the most confusing aspects of gelatinous pelagic life is the fact that some animals switch from being attached and living completely static (sessile) lives, to being pelagic (moving around like jellyfish) for parts of their life. Many stately corals spend part of their life cycle in a planktonic, free-moving form. Learning more has clarified for me that a little bit of knowledge is just that … a little bit.

It has taken laborious hours for me to try to classify the photos we have. Our marine identification teachers in Vancouver - Donna Gibbs and Andy Lamb were such experts. When they leave their dive, they merely check through a computerized list of hundreds of animals, and they check off each of those they remember seeing. Through looking at our photos, we often find many animals that we hadn't even noticed when we were diving.

For his skills as a scientist, an educator and a lifelong proponent for marine preservation Andy Lamb has recently been made a Fellow of the Royal Canadian Geographic Society. He's a great expert. Where I'm pleased to be nearing 500 dives, he's now completed nearly 10 times that many - 5,000 mostly cold-water dives.


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At 2017-12-18 08:36 (utc) our position was 43°56.64'S 073°47.12'W

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