Saturday, July 26, 2014

Trawling for Fish on the Centennial

The Fish Class here at Friday Harbor Labs went out on our research vessel, the Centennial, and bottom-trawled for fish. I tagged along to nab any sculpin that might show up.

Fast facts: Sculpin are spiny bottom-fish in the superfamily Cottidae. There are 756 sculpin species worldwide! The species we're studying have huge mouths which they use to capture live shrimp and fish. Here's a video of our Great Sculpin (Myoxocephalus polyacanthocephalus -- yes we have to learn that name) hunting a shrimp:


Working on the Centennial was a boat-load of fun! I spent a while on the bridge with our captain listening to tales of enormous ocean swells and Antarctic ice-breaking. I learned about all the equipment, from two-way radios and bathymetric charts to sonar seafloor profiles and all-inclusive GPS maps. (I'm pretty sure all those names are wrong! But you get the idea.)

Our fearless captain.

Here we are waiting for the trawl net to arrive.

And here is our second trawl net arriving. Can you guess what type of bottom we trawled on? (The options are rocky, sandy, or muddy...)



Then came the fun part. We got to search through bucketloads of mucky sediment and pull out anything cool!

Sorting through the trawl muck.

I learned a ton by talking to all the experts on board. For example, we once pulled up a Pacific sanddab (Citharhicthys sordidus),  a "sinistral flatfish." What does that mean, you ask? Well I asked, too, and it means that both eyes migrate to the fish's left side as it matures. I then learned that "sin" is Latin for "left," an words like "sinner" and "sinister" come from our ancient association of "left" with"evil." I'm not sure how accurate the etymological lesson was, but these folks sure did know their fish!

"I got a flatty!"

We pulled up nine spiny dogfish (a small species of shark), dozens of flatfish, hundreds of shrimp, and a whole mess of kelp. There were also lovely invertebrates of all kinds, but I could tell the Fish Class students had a soft-spot for the vertebrates.

A common sunstar (Crossaster papposus).

There were also a couple Algae Class teachers on board, so I took the opportunity to brush up on my marine plants. Did you know the "algae" is not a scientific term? Things called "algae" might actually be plants, bacteria, or something else entirely. But "seaweed" is a technical term. There are three types of seaweed algae:
  1. Brown (olive brown in color; for example Bull Kelp)
  2. Green (grass green in color; for example Sea Lettuce)
  3. Red (can be any color other than olive-brown or grass-green!)
Now you know more about the ocean! Aren't you glad? :)

1 comment:

  1. I think your etymological lesson was correct. Sin = left, dexter = right. One opposite of right is "wrong", another is "left." Right-handed is good, we are dextrous, someone using both hands well is ambidextrous = two right hands. Left-handed is bad, sinister, a clumsy person has two left feet. A bias to be sure.
    Glad that you found a live sand-dab, as the one I found at Carkeek was dead. It is undoubtedly an "abundant" fish. (just like in birding) :-) I would have loved to sort through that mud with you all.

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