otoliths – Page 5 – NOAA Teacher at Sea Blog

July 18, 2011April 28, 2021

Anne Mortimer: Swell Sleeping, July 12, 2011

NOAA Teacher at Sea
Anne Mortimer
Onboard NOAA Ship Oscar Dyson
July 4 — 22, 2011

Mission: Pollock Survey
Geographical area of cruise: Gulf of Alaska
Date: July 12, 2011

Weather Data from the Bridge
Conditions: Foggy and windy, changing to partly sunny and windy
Air Temperature: 10.1 ⁰C
Sea Temperature: 7.6 ⁰C
Wind direction: 237 ⁰C
Wind speed: 20 knots
Wave height: 2-3 ft.
Swell height: 5-6 ft.

Science and Technology Log

Last night we had a “splitter” catch. The scientists found an area that they couldn’t pass up fishing, so at about 9pm the trawl was put in the water. The 540 ft. long Aleutian wing trawl brought in lots of pollock and Pacific ocean perch, a type of red-colored rockfish. A catch is called a splitter when it is so big it won’t all fit on the table. To get a weight of the whole catch, the deck crew use a crane to weigh the net, then empty it out. Then the catch is dumped into a bin that is split in two parts. Only one part of the bin is then raised, putting a sub-sample on the table to be worked-up. It took a long time to process all of the catch. We separated the species on a conveyor belt system, then the messy stuff happens. I mentioned that otoliths and stomachs are collected, but I don’t think I emphasized just how gross this can be. To sex the fish, we use a scalpel to slice the fish down the side, then look for larger pink-colored ovaries or a stringy, twisted looking testes. To collect otoliths, the fish skull is cut just behind the eyes and cracked open. The otoliths are then picked put with tweezers. If you are really good at pulling otoliths, you can pull both at once, which can be very challenging. My double-take record is only 2 in a row, but I’ve pulled both at once at least 5 times now! The last messy thing is stomach collection. You can imagine what this entails, I’m sure. I’m happy to say that I’ve only had to hold the baggie for the stomach, not cut any out! Processing this catch took several hours– we didn’t end until after 1am.

red rockfish — This red-colored fish is a pacific ocean perch, or P.O.P. to a fish biologist.

When I am not processing a trawl or on the bridge observing, I have been working to annotate some videos from the cam-trawl. The cam-trawl is a stereo-camera system that takes snapshots of whatever comes through the net. This cam-trawl was designed by several of the scientists on the pollock survey. They are hoping it will help lead to less actual fish samples needed if the images can accurately provide evidence of species, numbers, and sizes. Some trawls would still have to be taken aboard for sexing, weights, and otolith and stomach samples. Annotating the images basically means that I click through the images, counting each species of fish or invertebrate (usually jellies) that I see. This can very tedious, but the whole idea of the project is very exciting. I’ll talk more about the cam-trawl and this technology in my next blog.

Personal Log

Yesterday was my first real encounter with rocking and rolling on the Oscar Dyson. The winds were blowing at about 30 knots (that’s about 35 mph), and there was a lot of swell. Swell waves are long-wavelength surface waves that could have originated from a storm hundreds or thousands of miles away. The combination of these two made for a very rocky ride until we hid behind an island until sunrise. Since I go to bed at 4:30am, it wasn’t long before the boat was headed back out to unprotected waters, and I was rudely awakened by the swell. To say I didn’t have a swell sleep is an understatement. I had to take a nap this evening to compensate for my lost hours!

July 14, 2011April 28, 2021

Kathleen Harrison: Fish Stick, Anyone? July 15, 2011

NOAA Teacher at Sea
Kathleen Harrison
Aboard NOAA Ship Oscar Dyson
July 4 — 22, 2011

Location: Gulf of Alaska
Mission: Walleye Pollock Survey
Date: July 15, 2011

Weather Data from the Bridge
True Wind Speed: 34 knots, True Wind Direction: 284.43
Sea Temperature: 10.02° C, Air Temperature: 11.34° C
Air Pressure: 1014.97 mb
Latitude: 56.12° N, Longitude: 152.51° W
Sunny, Clear, Windy, 10 foot swells
Ship speed: 10 knots, Ship heading: 60°

Science and Technology Log

The Walleye Pollock is an important economic species for the state of Alaska. It is the fish used in fish sticks, fish patties, and other processed fish products. Every year, 1 million tons of Pollock are processed in Alaska, making it the largest fishery in the United States by volume. The gear used to catch Pollock is a mid-water trawl, which does not harm the ocean floor, and hauls are mostly Pollock, so there is very little bycatch.

table full of pollock — A sample of pollock that the Oscar Dyson caught for scientific study. A "drop" in a very large "ocean" of pollock industry.

Although Pollock fishermen would like to make as much money as they can, they have to follow fishing regulations, called quotas, that are set each year by the North Pacific Fishery Management Council (NPFMC). The quotas tell the fishermen how many tons of pollock they can catch and sell, as well as the fish size, location, and season. The NOAA scientists on board NOAA Ship Oscar Dyson have an important role to play in helping the NPFMC determine what the quotas are, based on the biomass they calculate.

The quotas are set in order to prevent overfishing. Pollock reproduce and grow quickly, which makes them a little easier to manage. When fishing is uncontrolled, the number of fish becomes too low, and the population can’t sustain itself. Imagine being the lone human in the United States, and you are trying to find another human, located in Europe, only you don’t know if he is there, and all you have is your voice for communication, and your feet for traveling. This is what happens when fish numbers are very low– it is hard for them to find each other.

There are many situations where uncontrolled fishing has cost the fishermen their livelihood. For example, in the early 1900s, the Peruvian Anchovy was big business in the Southeast Pacific Ocean. Over 100 canneries were built, and hundreds of people were employed.

anchovy catch graph — This graph shows how the Peruvian Anchovy catch rose to record heights in 1970, then collapsed in 1972. This could have been prevented by effective fishery management.

Scientists warned the fishermen in the 1960s that if they didn’t slow down, the anchovies would soon be gone. The industry was slow to catch on, and the anchovy industry crashed in 1972. The canneries closed, and many people lost their jobs. This was an important lesson to commercial fishermen everywhere.

The Walleye Pollock (Theragra chalchogramm) is a handsome fish, about 2 feet long, and greyish – brown. Most fishermen consider him the “dog” food of fish, since he pales in comparison to the mighty (and tasty) salmon. Nonetheless, Pollock are plentiful, easy to catch, and thousands of children the world over love their fish sticks.

Besides calculating biomass, there are 2 other studies going on with the Pollock and other fish in the catch. Scientists back at the Alaska Fisheries Science Center (AFSC) in Seattle are interested in how old the fish are, and this can be determined by examining the otoliths.

2 pollock otoliths — Here are 2 otoliths from a pollock. The one on the left shows the convex surface, the other shows the concave surface.

These are 2 bones in the head of a fish that help with hearing, as well as balance. Fish otoliths are enlarged each year with a new layer of calcium carbonate and gelatinous matrix, called annuli, and counting the annuli tells the scientists the age of the fish. Not only that, with sophisticated chemical techniques, migration pathways can be determined. Amazing, right? The otoliths are removed from the fish, and placed in a vial with preservative. The scientists in Seattle eagerly await the return of the Oscar Dyson, so that they can examine the new set of otoliths. By keeping track of the age of the fish, the scientists can see if the population has a healthy distribution of different ages, and are reproducing at a sustainable rate.

Another ongoing study concerning the Pollock, and any other species of fish that are caught during the Pollock Survey, deals with what the fish eat.

stomach being put into a bag for later study — A pollock stomach is put into a fabric bag, which will be placed in preservative. Scientists at the Alaska Fisheries Science Center will study the contents to determine what the fish had for lunch.

Stomachs are removed from a random group of fish, and placed into fabric bags with an ID tag. These are placed into preservative, and taken to Seattle. There, scientists will examine the stomach contents, and determine what the fish had for lunch.

Personal Log

I learned about fishing boundaries, or territorial seas, today. In the United States, there is a 12-mile boundary from the shore marked on nautical charts. Inside this boundary, the state determines what the rules about fishing are. How many of each species can be kept, what months of the year fishing can occur, and what size fish has to be thrown back. Foreign ships are allowed innocent passage through the territorial seas, but they are not allowed to fish or look for resources. Outside of that is the Economic Exclusion Zone (EEZ) which is 200 miles off shore. The EEZ exists world-wide, with the understanding among all international ships, that permits are required for traveling or fishing through an EEZ that does not belong to the ship’s native country.

Everyone was tired at the end of the day, just walking across the deck requires a lot more energy when there are 10-foot swells. Check out this video for the rolling and pitching of the ship today.

July 12, 2011April 28, 2021

Anne Mortimer: Otoliths and more otoliths…, July 8, 2011

NOAA Teacher at Sea
Anne Mortimer
Onboard NOAA Ship Oscar Dyson
July 4 — 22, 2011

Mission: Pollock Survey
Geographical area of cruise: Gulf of Alaska
Date: July 8, 2011

Weather Data from the Bridge
Air temperature: Sunny, 10°C
Sea temperature: 9.1°C
Wind direction: SW; 318 degrees
Wind Speed: 24.1 knots
Barometric pressure: 1012.12 mbar

Science and Technology Log

On my last 12 hour shift, a beautiful, sunny day, we started by pulling in, sorting, counting, and weighing fish caught in a mid-water trawl. The scientists were also testing out a new “critter cam” that was attached to the net. The trawl net has a special device called a M.O.C.C. which stands for Multiple Opening and Closing Cod-ends. The net has three separate nets that can be opened and closed by the M.O.C.C. when the scientists reach the desired depth or location for catching, this keeps the catches from different targeted depths from mixing together. The three separate nets are called cod-ends. Each cod-end catch is processed separately. In this trawl, we saw multiple jellies, juvenile pollock, krill, juvenile squid, juvenile Pacific sandlance, capelin, juvenile flatfish, and juvenile cod.

capelin — Capelin from our trawl covered the deck of the boat.

MOCC entering the water — The Multiple Opening and Closing Cod-end, or MOCC, and net being released to the water for a mid-water tow.

Later, we trawled a 2nd time for about an hour. The trawl net used is called the AWT or Aleutian Wing Trawl because the sides of the net are like wings. After the net is in the water, two large steel doors are dropped in the water and help to pull the net open wide. You can see them in the picture above, they are the giant blue steel plates attached to the very stern (end) of the ship. During this trawl, only one cod-end was opened, and the catch was several hundred pounds of Pollock, with some eulachon, capelin, squid and jellies also.

Because pollock are the target fish of this survey, each was sexed and counted, and a smaller number were measured for length and weight, and the stomachs and otoliths were removed. The stomachs are being preserved for another research project back in Seattle, and as I mentioned previously about otoliths, they tell the age of the fish.

Personal Log

Today I was happy to have beautiful sunshine and 2 trawls to sort through. The skies and surrounding islands were absolutely stunning. I can understand why people are drawn to this place. It’s wild and rugged and looks like it probably did hundreds of years ago.

shumigans — Scenery of the Shumigan Islands.

Species List

humpback whale (just one today!)

fulmar

tufted puffin

pollock

arrowtooth flounder

jellies

krill

squid

Pacific sandlance

capelin

juvenile flatfish

juvenile cod

sea gulls

eulachon

Thought for the day… if I was a blubbery whale, I would live in the Gulf of Alaska. If I was a pollock, I’d try not to get into a net, they can give you a splitting headache.

July 5, 2011April 28, 2021

Steven Wilkie: July 4, 2011

NOAA TEACHER AT SEA
STEVEN WILKIE
ONBOARD NOAA SHIP OREGON II
JUNE 23 — JULY 4, 2011

Mission: Summer Groundfish Survey
Geographic Location: Northern Gulf of Mexico
Date: July 4, 2011

Ship Data

Latitude	29.31
Longitude	-94.79
Speed	0.00 kts
Course	172.00
Wind Speed	4.99 kts
Wind Dir.	268.67 º
Surf. Water Temp.	30.60 ºC
Surf. Water Sal.	24.88 PSU
Air Temperature	30.70 ºC
Relative Humidity	68.00 %
Barometric Pres.	1014.50 mb
Water Depth	10.40 m

Personal Log

My final watch ended last night with what was one of our largest catches of the trip. The knowledge that it was our last trawl–well mine at least–and the Oregon II will head back out in a few days for its final leg of the ground fish survey, allowed us to knock it out in no time.

Our Final Catch Onboard — Our final (and one of our largest) catches waiting to be sorted.

It is amazing how similar my experience has been on this trip to the experiences I have with my students in my classes at school. They come in “green” on the first few days of class: some of them have a some background knowledge, some of them have little, but slowly but surely as we build on their existing knowledge they get to a point where they are confident enough to speak up about issues and content that we have been discussing. Towards the end of the year, they can link the ideas of what was talked about at the beginning of the year to what we discussed the week before final exams. Everything is connected.

I feel now, how I hope my students feel on their last few days of my classes. A sense of understanding, a battery of skills that I didn’t have when I started now at my disposal, and an appreciation for what it is that the people who taught me know and do on a daily basis. In all of my years of professional development, summer workshops and the like, I can say that none has been as enjoyable or rewarding as this experience.

Refreshing Old Skills — With the help of chief scientist Michael Hendon, I remove the otiliths (ear bones) from a snapper. These bones can be used to help determine the age of a fish.

I came into the Teacher at Sea program with a good sense of the marine environment, and I have relied heavily on NOAA’s resources for years to help my students better understand the ocean and its processes. But to see firsthand how some of that information is gathered and to get a sense of how hard these scientists work to ensure their data and procedures are valid is both commendable and reassuring, as I am consistently telling my students how good procedures will lead them to good data, and will, in turn, allow them to draw well-supported conclusions.

I pride myself on the hands-on approach I bring to science in my classroom, and nothing is more hands on then being elbow deep in 600 croakers flopping on the deck! Everyone learns differently. I am a learn-by-doing kind of guy, and I try to provide as much of that in my classroom as possible, but even doing something doesn’t guarantee that you will understand it–that often requires a good teacher. The Oregon II’s crew is the epitome of good teachers in action. I have to personally extend a thank you to Brittany Palm, my watch leader, and Michael Hendon the chief scientist on board. Both of these gifted scientists helped me go from a fumbling, taxonomically challenged amateur, to a less fumbling, taxonomically appreciative assistant in training! Their patience as we butchered scientific names and misidentified organisms allowed us to slowly but surely get a better understanding of the procedures until we could practically work up a catch on our own. Well, we left the fish we couldn’t identify for them, but none the less….

I am happy to be heading home to my family and to a more regular work day (12 hour shifts are tough), but I do think I will miss the experience and the camaraderie among the people on the ship, and the soothing rhythm of the ship’s engines and the waves. I hope those of you that read this get a sense of what an awesome experience this is, as well as take away the importance of the work that NOAA does, and the need for it!

The A-Team — My watch on our last day, notice how happy we are! From left Michael Hendon (chief scientist), me, Amy Schmitt, Kristin Foss, Brittany Palm (watch leader).

June 29, 2011April 28, 2021

John Taylor-Lehman, June 29, 2011

NOAA Teacher at Sea
John Taylor-Lehman
Onboard R/V Savannah
June 24 – July 1, 2011
NOAA Teacher at Sea: John Taylor-Lehman
Ship: R/V Savannah
Mission: Fisheries Survey
Geographical area of the cruise: Continental Shelf off of Florida
Date: Wednesday, 29 June 2011

Weather Data from the Bridge
Longitude. 80.15
Latitude 29.08
Salinity 36.343
Temperature 27.25
Barometric pressure 32.00
Depth 47.7 m
Winds S,SW 26 knots

Science and Technology Log

We continue to bait and deploy traps during the daylight hours. Three sets of 6 traps are typically deployed at one location. On Tuesday, 4 sets were deployed because of the low number of fish caught on the previous 3 sets.

There is an art to selecting sites and retrieving traps. Some traps can get hung-up on the ledges they were meant to be resting upon. Our Chief Scientist, Nate Bacheler, must communicate with the winch operator and captain with gestures to subtly move the tether in the hopes of freeing the trap. In rare events, a trap can be lost.

Here I am getting ready to deploy a fish trap. On the right is the camera that goes on the front of the trap. — Camera on top of the fish trap.

Mounted on each trap are 2 video cameras. They record the habitat and activity in the vicinity of the trap. The resolution on the videos is remarkable! During the winter months the films will be viewed and the fish species identified and counted.

What Happens to the Data?

Eric taking measurements on a Red Snapper

The data collected on these cruises allows scientists to create an “index of abundance” for each species of interest. This information is combined with information from other sources and in-put to an existing assessment (population) model. The South Atlantic Fisheries Management Council then looks at the output from the model to decide on management regulations. They’ll decide on loosening or strengthening harvesting rules for each species.

So What Happens Once the Fish Are Caught?

There is a great deal of information collected on each fish caught. For example: site location, weight, species, total length, length to fork in tail, and length before the tail. Select fish are later dissected to collect their otoliths (a bone in the head that can be used to determine age) and gonads (for maturity and sex determination). All fish are kept on ice in a large cooler until they are processed. Some of the fish are filleted, wrapped and frozen to ultimately be given away to charity.

Personal Log

I no longer see the placid Atlantic under the ship. Strong winds (40 knots) have been blowing and stirring up the surface, creating 3-4 ft. waves and at times 4-5 ft. My stomach has noticed the change in conditions so I have been trying to keep busy and my mind distracted. Tried chewing some ginger, a remedy many people have suggested. Later, as the seas calmed and/or the ginger took effect, my stomach settled.

The weather conditions have stimulated much discussion among the science staff and crew. It was decided that conditions were ok to deploy the traps but too “sketchy” to retrieve them safely.

The chief scientist seems to have many contingency plans for when the weather does not cooperate. Decisions can be made at a moment’s notice to head to another site or cancel the trap drops. The fall back plans maximize the productivity of the research with the limited time at sea. The “down” time has given me some extra time to interview the science staff and crew. They are all very interesting people.

Zeb , David and Nate, members of the science crew

New animal sightings: (birds) brown boobies, yellow-throated warbler, Wilson’s storm-petrel, royal terns, (fish) reticulated moray eel, purplemouth moray, and red porgy.