Emily Sprowls: It’s a shark eat shark world down there! March 22, 2017


NOAA Teacher at Sea

Emily Sprowls

Aboard Oregon II

March 20 – April 3, 2017

 

Mission: Experimental Longline Survey

Geographic Area of Cruise: Gulf of Mexico

Date: March 22, 2017

Science and Technology Log

This first leg of the Oregon II’s research for the season is an experimental longline survey. This is an exciting cruise for everybody, as we are all anxious to see what comes in on each line, and we hope to find some rare and little-studied species.

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               Reeling in a shark caught on one of the longline hooks 

A longline is a type of fishing gear that deploys one very long and very thick fishing line with many hooks attached. A fisheries survey is a systematic sampling of the ocean to assess fish populations. This mission is experimental because we are testing the longline at extreme depths and we are using different kinds of hooks in order to catch as wide a variety of species as possible.

Things have been busy onboard from the very first day, as we have been setting out and hauling longlines around the clock. We are headed deeper and deeper into the Mississippi canyon of the Gulf of Mexico with each station, starting at 100m and have worked our way down to 750 m, where we currently have a line “soaking” before we haul it up to record what we caught.

Personal Log

Life on the ship is divided into night and day watch. I’m “on days,” which means I work noon to midnight. I am so lucky to be a cruise with a lot of seasoned marine scientists and a great, hard-working crew. Shark scientist Kristin Hannan is the Field Party Chief and has taken me under her wing to get me settled and teach me as much as she can (without making me feel like the newbie that I am)!

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Oil rigs on the horizon

The seas have been calm and the water is the most beautiful color of blue! We are pretty far out to sea, and I have been amazed to see so many oil rigs off in the distance. They glow like small cities at night, and I think they look like strange robots walking on the horizon during the day.

 

Kids’ Questions of the Day

These questions are from the 1st-2nd grade and multi-age classes at Harmony School.

  •  How do you catch the sharks?

We catch the sharks by setting out 100 baited hooks at a time on a very long fishing line. A winch reels in the 3 miles of line after a couple of hours, and we record what is on every single hook.

  • How do you find the sharks?

We rely on the sharks finding our baited hooks. We put weights on the line so that it will sink all the way down to the bottom. We are fishing so deep that it takes almost an hour just for the line to sink! The sharks find the bait using their incredible sense of smell.

  •  What do sharks eat? Fish? Squid? Cookies? Other sharks?

We are baiting the hooks with pieces of squid. The process of baiting hundreds of hooks has left my clothes covered with squid ink!

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Hooks baited with pieces of squid

Sometimes they catch sharks with fish (mackerel), but squid bait stays better on the hooks, and deep-sea sharks clearly like squid, which also live in deep water. While this mission is experimental, the scientists onboard do not think we will have much luck baiting a hook with a cookie – it will just dissolve in the sea (besides the cookies in the galley are so delicious that there are no leftovers)! One type of deep-sea shark makes their own cookies… cookie-cutter sharks (Isistius) bite “cookies” out of other fish with their amazing jaws. Maybe we’ll catch one!?!

Last night we hauled in one hook with only a shark head on it…. What do you think happened to the rest of the shark?

 

One response to “Emily Sprowls: It’s a shark eat shark world down there! March 22, 2017

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