Kathy Schroeder: Retrieving the Longline, September 30, 2019


NOAA Teacher at Sea

Kathy Schroeder

Aboard NOAA Ship Oregon II

September 15-October 2, 2019


Mission: Shark/Red Snapper Longline Survey

Geographic Area of Cruise: Gulf of Mexico

Date: 9/30/19

Weather Data from the Bridge

Latitude: 29.47408
Longitude: 85.34274
Temperature: 85°F
Wind Speeds: E 5 mph


Science and Technology Log

Retrieving the Longline

One hour after the last highflyer is entered into the water it is time to retrieve the longline.  The ship pulls alongside the first highflyer and brings it on board.  Two people carry the highflyer to the stern of the ship.  The longline is then re-attached to a large reel so that the mainline can be spooled back onto the ship.  As the line comes back on board one scientist takes the gangion removes the tag and coils it back into the barrel.  The bait condition and/or catch are added into the computer system by a second scientist.  If there is a fish on the hook then it is determined if the fish can be brought on board by hand or if the cradle needs to be lowered into the water to bring up the species. 

Retrieving the high flyer
Retrieving the high flyer on the well deck

Protective eye wear must be worn at all times, but if a shark is being brought up in the cradle we must all also put on hard hats due to the crane being used to move the cradle.   Once a fish is on board two scientists are responsible for weighing and taking three measurements:  pre-caudal, fork, and total length in mm.  Often, a small fin clip is taken for genetics and if it is a shark, depending on the size, a dart or rototag is inserted into the shark either at the base of the dorsal fin or on the fin itself.   The shark tag is recorded and the species is then put back into the ocean.  Once all 100 gangions, weights and highflyers are brought on board it is time to cleanup and properly store the samples. 

sandbar shark
Taking the measurements on a sandbar shark (Carcharhinus plumbeus) Measurements: 1080 precaudal, 1200 fork, 1486 total (4’10”)l, 20.2 kg (44.5 lbs)
tagging smoothhound
Placing a rototag in a Gulf smooth-hound (Mustelus sinusmexicanus)
Tiger shark on cradle
Tiger shark (Galeocerdo cuvier) on the cradle getting ready for a dart tag
data station
Data station for recording measurements, weight, sex, and tag numbers

Fish Data: Some species of snapper, grouper and tile fish that are brought on board will have their otoliths removed for ageing, a gonad sample taken for reproduction studies and a muscle sample for feeding studies and genetics.  These are stored and sent back to the lab for further processing. 

red snapper samples
red snapper (Lutganidae campechanus) samples: gonad (top), muscle (middle), otoliths (bottom)


Personal Log

It has been a busy last few days.  We have caught some really cool species like king snake eels (Ophichthus rex), gulper sharks (Centrophorus granulosus), yellow edge grouper (Hyporthodus flavolimbatus) and golden tile fish (Lopholaatilus chamaeleontiiceps).  There have been thousands of moon jelly fish (Aurelia aurita) the size of dinner plates and larger all around the boat when we are setting and retrieving the longline.  They look so peaceful and gentle just floating along with the current.  When we were by the Florida-Alabama line there were so many oil rigs out in the distant.  It was very interesting learning about them and seeing their lights glowing.  One of them actually had a real fire to burn off the gases.  There were also a couple sharks that swam by in our ship lights last night.  One of the best things we got to witness was a huge leatherback sea turtle (Dermochelys coriacea) that came up for a breath of air about 50 feet from the ship. 

yellow-edge grouper
yellow edge grouper (Hyporthodus flavolimbatus) 891 mm (2′ 11″), 9.2 kg (20.3 pounds)
king snake eel
king snake eel (Ophichthus rex)
king snake eel close-up
king snake eel (Ophichthus rex)

26 responses to “Kathy Schroeder: Retrieving the Longline, September 30, 2019

  1. How long is the longline and what was the approx. number of organisms surveyed? Where there more sharks than snappers or vice-versa?

  2. How long, on average, does it take to bring up the species that’s been caught, measure it, and return it back to the ocean?

  3. I am happy to see the amount of safety measurements the team takes by wearing safety goggles and hard hats with a big catch. There are so many great standards shown, hopefully making it easier for you guys to perform and record the most accurate measurements.

  4. I love all the different species shown. This must be a life and perspective changing experience. Especially due to your field. You must learn so much and translate this into your work.

  5. I didn’t think that there would be sharks that were only four feet and ten inches long. It’s incredibly interesting how big or small the varying species of sharks can be. Getting to see pictures of the fish that are caught is very exciting as well.

  6. Whoa Mrs. Schroeder you have caught a lot of interesting species on your trip. It is amazing to see the amount of creatures that are living in these ocean ecosystems. So would all of these species be part of the same food chain or do they live separately in different areas of the ocean?

  7. Hello Ms.Schroeder, is there is any other way to find out about a fish and its past besides extracting/removing it’s otoliths?

  8. Retrieving the longline and all your tasks throughout the blogs seem pretty difficult and tiring. I hope you come back soon!

  9. The large tiger shark looks amazing, I am curious to how old that tiger shark is and how long they live for in the wild. I think it is crazy what odd creatures live in the oceans, and why so large eyes on the grouper.

  10. I found all the procedures and activities very interesting and would like to know the requirements to practice in an activity like this in the future. 🙂

  11. I was just wondering, because I don’t know much about the process of catching fish and sharks, what keeps the creatures attached to the longline once they’ve taken the bait?

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