Emina Mesanovic, Goodbye Pisces, August 1, 2014


NOAA Teacher at Sea

Emina Mesanovic

Aboard NOAA Ship Pisces

July 20 – August 2, 2014

Mission: Southeast Fishery- Independent Survey

Geographic area of the cruise: Atlantic Ocean, off the coast of North Carolina and South Carolina

Date: August 1, 2014

Science and Technology Log

After the fish are weighted and measured some are returned to the sea and others are kept for further study. For the fish that are kept the Pisces scientists usually keep two parts of the fish the otoliths and a part of the gonads (reproductive organ).

As I mentioned in an earlier post the otoliths are the fish ear bones, which can be used to determine the age of the fish. The otoliths are located behind the eyes so scientists use a knife to cut through the head being careful not to break the otoliths. They are removed from the fish rinsed in water and put into a labeled envelops to be taken back to the lab for further study.

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White Grunt Otolith
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Location of Fish Otolith. Picture from NOAA

Scientists are also interested in studying fish gonads to understand more about fish growth and reproduction, which is important for helping maintain a healthy fish population. You don’t want to catch fish before they are old enough to reproduce. The NOAA scientists use tissue teks to collect a small section of the gonads. Each fish is given a number based on the trap that it was caught in, this number is printed on the tissue tek and the envelop with the fish otoliths.

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Diagram of fish gonads. Picture from marshall.edu
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Tissue Tek, on the Pisces different species of fish get different colored tissue teks.

When the gonads are removed sometimes they are very small and thin and fit easily into the tissue tek but often times they have to be trimmed to fit. You don’t want to overfill the tissue tek because you may destroy the sample or cause it to spoil if the chemical preservative can’t get into the middle of the sample.

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Examples of tissue teks that were not properly prepared. Picture from NOAA.

Back at the lab scientists slice the tissue into thin strips and examine it under a microscope to determine development: presence of eggs, size of eggs.

Fish Gonads under the microscope. Picture from NOAA.
Fish Gonads under the microscope. Picture from NOAA.

Did you know that fish can be male, female or transgender. Some fish start out as females when they are young and become male as they mature.

Personal Log

I have to tell you, typing a blog while my body sways from one side to the other is very strange. I still have to take a Dramamine after I wake up and I have to sit down when the water gets rough, however life on the ship has gotten easier. We have been fortunate to have great weather for our two week cruise, it only rained on our last day out at sea. I can’t believe that tomorrow we will be back in Morehead City, North Carolina.

Sunrise on the top deck of the Pisces.
Sunrise on the top deck of the Pisces.

A warm thank you to all the crew and scientists aboard the Pisces. I have learned so much and will take back to my classroom a new excitement and love of the ocean. I will be able to introduce my students to what it means to be a scientist at sea and how what we learn in the classroom translates to what they can do in the future. I have enjoyed getting to know you and hearing about your lives. You are a talented group of people.

We saw some dolphins on Thursday night.
We saw some dolphins on Thursday night.

COOL CATCH OF THE DAY

a pair of butterfly fish (every time we have caught them they have come in a pair)
A pair of butterfly fish (every time we have caught them they have come in a pair)

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