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Did You Know Most Animals in the Ocean Don’t Have Backbones?

April 15, 2019

Christine Kircun, biological science technician, inspects a rich diversity of bottom-dwelling sea creatures brought up in an early-morning survey tow off Chatham, Massachusetts


We’re half a week into this leg of the Northeast Fisheries Science Center's spring bottom-trawl survey and settling into survey life. Our first tow this morning, around 1:30 a.m., was a little southeast of Chatham Harbor off Cape Cod.  Even though the catch was fairly small, it was full of really interesting benthic invertebrates—animals that live on the ocean floor and lack a vertebrae or backbone. 

It's always fun to see tows like these. Even though it may be hard to pick through on the sorting belt, it’s a great opportunity to see the diversity of life that lives on the ocean floor.

At first, it may seem difficult to get a grasp of what you’re looking at but it becomes much easier to comprehend after taking some time to separate everything into groups. These were the highlights of what I found:

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Benthic invertebrates. Photo: NOAA Fisheries

Once these were sorted, I had an easier time identifying the collection: a mussel, some sea stars, sponges, a sea mouse, comb jelly, sand dollar, sea urchin, and fish eggs.

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Fish eggs. Photo: NOAA Fisheries

Larval fish visible in a clump of fish eggs. Note the empty egg in the lower right hand corner of the picture.

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Orange-footed sea cucumber. Photo: NOAA Fisheries

Orange-footed sea cucumber, Cucumaria frondosa. I quickly placed this animal in a bucket of fresh salt water. After some time, it relaxed enough to expose its tentacles. It was surprising to see!  In my experience, they are mostly seen closed up after coming up in the net.

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Last updated by Northeast Fisheries Science Center on October 09, 2019