Kristin Hennessy-McDonald: Apex Predators, September 20, 2018


NOAA Teacher at Sea

Kristin Hennessy-McDonald

Aboard NOAA Ship Oregon II

September 15-September 30, 2018

 

Mission: Shark/Red Snapper Longline Survey

Geographic Area of Cruise: Gulf of Mexico

Date: September 20, 2018

 

Weather Data from the Bridge

Latitude: 2759.75N

Longitude: 09118.52W

Sea Wave Height: 0m

Wind Speed: 3.72 knots

Wind Direction: 166.48֯

Visibility: 10 nautical miles

Air Temperature: 31.1

Sky: 5% cloud cover

 

Science and Technology Log

We’ve been out at sea for three full days now and have traveled along the Gulf coast from Alabama to Texas.  The Science Team has run mostly shallow longline sets during this time, meaning that we have fished in depths from 9 to 55 meters.  As we move forward, we will fish stations at these depths and stations at depths of 55 to 183 meters, and from 183 to 366 meters.  The locations of the stations are randomized based on depth and the area that is being fished.  Due to the weather that hit south Texas the week before we joined this leg of the survey, we have been fishing the area that was impassable on the last leg of the survey.

As a member of the science team, there are five jobs that need to be done on each side of the set.  When the line is being cast, someone needs to release the highflyer, clip numbers, sling the bait, work the computer, or cleanup.  When the line comes in, there is a data collector, 2 fish handlers, a hook collector, and the computer person.  The highflyer is the marker that is put on either end of the line, so that the line can be seen from the bridge.  The data that is collected on paper and on the computer on each fish includes the number of the hook that they are on, species, length, and gender.  Additionally, some sharks are tagged and a fin clip is taken.

After a line is set, we check the water using a CTD (Conductivity Temperature Depth) Probe.  It has a GoPro video recorder that takes a video of the water and the sea floor at the site of the line.

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Field Party Chief Kristin Hannan setting up the CTD

 

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CTD ready for deployment

A few of the highlights from the catches so far:  We had one catch that was coming up with mostly empty hooks, but then we caught a scalloped hammerhead shark (Sphyrna lewini).  The shark was large enough that we used a cradle to pull it up to deck level.  I got to insert the tag right below the dorsal fin.

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Kristin Hennessy-McDonald tagging a scalloped hammerhead Photo Credit: Caroline Collatos

We had another survey that caught 49 sharks, including Atlantic Sharpnose Sharks (Rhizoprionodon terraenovae), Blacknose Sharks (Carcharhinus acronotus), Spinner Sharks (Carcharhinus brevipinna), and Blacktip Sharks (Carcharhinus limbatus).  Between these, we had a number of lines that brought up some sharks and a few Red Snapper (Lutjanus campechanus).  I have been able to dissect some of the Red Snapper, and collect their otoliths, which are their ear bones.

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Kristin Hennessy-McDonald holding a Red Snapper

In the time between setting and retrieving lines, one of the ways we kept ourselves busy was by cleaning shark jaws that we had collected.  I look forward to using these in my classroom as an example of an apex predator species adaptation.

Personal Log

During much the 12 hours of off time, I spend my time in my bunk.  Working for 12 hours in the hot sun is exhausting, and it’s nice to have the room to myself while I try to get some rest.  Though I share a bunk with another member of the Science Team, we work opposite shifts.  So, while I’m on deck, she’s sleeping, and visa versa.  As you can see, my daughter sent me with her shark doll, which I thought was appropriate, given that I was taking part in shark research on this ship.

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Kristin’s bunk on the Oregon II

While we were going slow one day, we had a pod of dolphins who swam along with us for a while.  They were right beside the ship, and I was able to get a video of a few of them surfacing next to us.

Did You Know?

Many shark species, including the Atlantic Sharpnose shark, are viviparous, meaning they give birth to live young.  These sharks form a placenta from the yolk sac while the embryo develops.

Quote of the Day

Without sharks, you take away the apex predator of the ocean, and you destroy the entire food chain

~Peter Benchley

Question of the Day

While it is a common misconception that sharks do not get cancer, sharks have been found to get cancer, including chondromas.  What type of cancer is that?

8 responses to “Kristin Hennessy-McDonald: Apex Predators, September 20, 2018

  1. Is it kind of sad that when I first saw Apex predators, I thought about the song from Mean Girls the Musical and then the animal group?

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