Kacey Shaffer: Fish Scales. Fish Tales. August 8, 2014

NOAA Teacher at Sea

Kacey Shaffer

Aboard NOAA Ship Oscar Dyson

July 26 – August 13, 2014

 

Mission: Walleye Pollock Survey

Geographical Location: Bering Sea

Date: August 8, 2014
Weather information from the Bridge:

Air Temperature: 11° C

Wind Speed: 27 knots

Wind Direction: 30°

Weather Conditions: High winds and high seas

Latitude: 60° 35.97 N

Longitude: 178° 56.08 W
Science and Technology Log:

If you recall from my last post we left off with fish on the table ready to be sorted and processed. Before we go into the Wet Lab/Fish Lab we need to get geared up. Go ahead and put on your boots, bibs, gloves and a jacket if you’re cold. You should look like this when you’re ready for work…

 

This is the gear you'll need in the Wet Lab. It can get pretty slimy in there! (Photo Credit: Emily)
This is the gear you’ll need in the Wet Lab. It can get pretty slimy in there! (Photo Credit: Emily)

The first order of business is sorting the catch. We don’t have a magic net that only catches Pollock. Sometimes we pick up other treats along the way. Some of the cool things we’ve brought in are crabs, squid, many types of jellyfish and the occasional salmon. One person stands on each side of the conveyor belt and picks these other species out so they aren’t weighed in with our Pollock catch. It is very important that we only weigh Pollock as we sort so our data are valid. After all the Pollock have been weighed, we then weigh the other items from the haul. Here are some shots from the conveyor belt.

 

Kacey lifts the door on the table so the fish will slide down onto the conveyor belt. This is when other species are pulled out. (Photo Credit: Sandi)
Kacey lifts the door on the table so the fish will slide down onto the conveyor belt. This is when other species are pulled out. (Photo Credit: Sandi)
At the end of the conveyor belt, Pollock are put into baskets, weighed and put into the sorting bin. (Photo Credit: Sandi)
At the end of the conveyor belt, Pollock are put into baskets, weighed and put into the sorting bin. (Photo Credit: Sandi)

Not every single fish in our net is put into the sorting bin. Only random selection from the catch goes to the sorting bin. The remaining fish from the haul are returned back to the sea. Those fish who find themselves in the sorting bin are cut open to determine their sex. You can’t tell the sex of the fish just by looking at the outside. You have to cut them open, slide the liver to the side and look for the reproductive organs. Males have a rope-like strand as testes. Females have ovaries, which are sacs similar to the stomach but are a distinctly different color.

 

This is the sorting bin. Can you guess what Blokes and Sheilas means?
This is the sorting bin. Can you guess what Blokes and Sheilas means?
The white, rope-like structure is the male reproductive organ.
The white, rope-like structure is the male reproductive organ.
The pinkish colored sac is one of the female's ovaries. It contains thousands of eggs!
The pinkish colored sac is one of the female’s ovaries. It contains thousands of eggs!
Kacey uses a scalpel to cut the fish. She slides the liver out and looks for the reproductive organs. Is it a male or female? (Photo Credit: Darin)
Kacey uses a scalpel to cut the fish. She slides the liver out and looks for the reproductive organs. Is it a male or female? (Photo Credit: Darin)

Okay, no more slicing open fish. For now! The next step is to measure the length of all the fish we just separated by sex. One of the scientists goes to the blokes side and another goes to the sheilas side. We have a handy-dandy tool used to measure and record the lengths called an Ichthystick. I can’t imagine processing fish without it!

The Ichthystick is used to record the length of fish. A special tool held in the hand has a magnet inside that makes a connection with a magnet strip inside the board. It automatically registers a length and records it in a computer program called Clams
The Ichthystick is used to record the length of fish. A special tool held in the hand has a magnet inside that makes a connection with a magnet strip inside the board. It automatically registers a length and records it in a computer program called Clams
Kacey measures the length of a male with the Ichthystick. She holds the tool in her right hand and places it at the fork in the fish’s tail. A special sound alerts her when the data is recorded. (Photo Credit: Darin)
Kacey measures the length of a male with the Ichthystick. She holds the tool in her right hand and places it at the fork in the fish’s tail. A special sound alerts her when the data is recorded. (Photo Credit: Darin)

That is the end of the line for those Pollock but we still have a basket waiting for us. A random sample is pulled off the conveyor belt and set to the side for another type of data collection. The Pollock in this special basket will be individually weighed, lengths will be taken and a scientist will determine if it is a male or female. Then we remove the otoliths. What are otoliths? They are small bones inside a fish’s skull that can tell us the age of the fish. Think of a tree and how we can count the rings of a tree to know how old it is. This is the same concept. For this special sample we remove the otoliths, which are labeled and given to a lab on land where a scientist will carefully examine them under a microscope. The scientist will be able to connect the vial containing the otoliths to the other data collected on that fish (length, weight, sex) because each fish in this sample is given a unique specimen number. This is all part of our mission, which is analyzing the health and population of Pollock in the Bering Sea!

Kacey scans a barcode placed on an otolith vial. Robert is removing the otoliths from each fish and Kacey places them in the vial. It is important to make sure the otoliths are placed in the vial that corresponds to the fish Robert measured. (Photo Credit: Emily)
Kacey scans a barcode placed on an otolith vial. Robert is removing the otoliths from each fish and Kacey places them in the vial. It is important to make sure the otoliths are placed in the vial that corresponds to the fish Robert measured. (Photo Credit: Emily)

 

Kacey removes an otolith from a fish Robert cut open. The otoliths are placed in the vial Kacey is holding. (Photo Credit: Emily)
Kacey removes an otolith from a fish Robert cut open. The otoliths are placed in the vial Kacey is holding. (Photo Credit: Emily)

At this point we have just about collected all the data we need for this haul. Each time we haul in a catch this process is completed. As of today, our survey has completed 28 hauls. Thank goodness we have a day shift and a night shift to share the responsibility. That would be a lot of fish for one crew to process! For our next topic we’ll take a look at how the data is recorded and what happens after we’ve completed our mission. By the way, “blokes” are males and “sheilas” are females. Now please excuse us while we go wash fish scales off of every surface in the Wet Lab, including ourselves!

Personal Log:

Just so you know, we’re not starving out here. In fact, we’re stuffed to the gills – pun completely intended. Our Chief Steward Ava and her assistant Adam whip up some delicious meals. Since I am on night shift I do miss the traditional breakfast served each morning. Sometimes, like today, I am up for lunch. I’m really glad I was or I would have missed out on enchiladas. That would have been a terrible crisis! Most people who know me realize there is never enough Mexican food in my life! Tacos (hard and soft), rice and beans were served along with the enchiladas. Each meal is quite a spread! If I have missed lunch I’ll grab a bowl of cereal to hold me over until supper. I bet you’ll never guess we eat a lot of seafood on board. There is usually a fish dish at supper. We even had crab legs one night and fried shrimp another. Some other supper dishes include pork chops, BBQ ribs, baked steak, turkey, rice, mashed potatoes, and macaroni and cheese plus there are always a couple vegetable dishes to choose from. We can’t forget about dessert, either. Cookies, cakes, brownies or pies are served at nearly every meal. It didn’t take long for me to find the ice cream cooler, either. What else would one eat at midnight?!

Ava and Adam are always open to suggestions as well. Someone told Ava the night shift Science Crew was really missing breakfast foods so a few days ago we had breakfast for supper. Not only did they make a traditional supper meal, they made a complete breakfast meal, too! We had pancakes, waffles, bacon, eggs, and hashbrowns. It was so thoughtful of them to do that for us, especially on top of making a full meal for the rest of the crew. Thanks Ava and Adam!

There are situations where a crew member might not be able to make it to the Mess during our set serving schedule. Deck Crew could be putting a net in or taking it out or Science Crew could be processing a catch. We never have to worry, though. Another great thing about Ava and Adam is they will make you a plate, wrap it up and put it in the fridge so you have a meal for later.

Like I said, we’re not going hungry any time soon! Here are some shots from the Mess Deck (dining room).

Mess Deck on the Oscar Dyson.
Mess Deck on the Oscar Dyson.
Mess Deck on the Oscar Dyson. Can you guess why there are tennis balls on the legs of the chairs?
Mess Deck on the Oscar Dyson. Can you guess why there are tennis balls on the legs of the chairs?
There are always multiple options for every meal. If you’re hungry on this ship you must be the pickiest eater on Earth!
There are always multiple options for every meal. If you’re hungry on this ship you must be the pickiest eater on Earth!

Did you know?

Not only are otoliths useful to scientists during stock assessment, they help the fish with balance, movement and hearing.

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