Bruce Taterka, July 8, 2010

NOAA Teacher at Sea: Bruce Taterka
NOAA Ship: Oregon II

Mission: SEAMAP Summer Groundfish Survey
Geographical Area of Cruise: Gulf of Mexico
Date: Thursday, July 8, 2010

Sexing the Catch

Weather Data from the Bridge

Time: 1630 (4:30 pm)
Position: Latitude = 28.20.93 N; Longitude = 095.58.98 W
Present Weather: Could cover 100%
Visibility: 4-6 nautical miles
Wind Speed: 18 knots
Wave Height: 6-8 feet
Sea Water Temp: 28.9 C
Air Temperature: Dry bulb = 27.2 C; Wet bulb = 25.3 C
Barometric Pressure: 1011.56 mb

Science and Technology Log

As you can tell from our previous blogs, we spend a lot of our time on the Oregon II counting, measuring and weighing our catch and loading the data into FSCS. These data are critical to NOAA and the states in managing fish stocks and the Gulf ecosystem. In addition to knowing population size, weights, and lengths of individuals it’s also important to know the sex of the organisms. Information on the male:female ratio helps NOAA and the states assess the ability of the population to reproduce, and to establish sustainable catch levels for commercial fishing.

But how do you determine the sex of marine organisms? For most fish and invertebrates you can only tell the sex by internal anatomy, which almost always requires cutting the animal open. This is time consuming and not always practical when we have a large catch to process and other tasks take priority, such as preparing samples to be analyzed for contamination from the oil spill which is our top priority right now.

For some organisms, however, sex can be determined externally. One of the things we’ve learned in the past week is how to determine the sex of shrimp, flatfish, crabs, sharks, skates and rays. Here’s how:

Shrimp: the males have a pair of claspers (called petasma) on their first set of legs.The petasma are absent in females. The males use the petasma during mating to grasp the female and transfer the sperm sac.

Male – arrows show the petasma

Female – petasma are absent

 

Crabs: On most crab species females have wide plates curving around the rear of the abdomen, while males have a long narrow plate or plates. On females, the eggs develop under the curved plate.

Male

Female

Female with eggs

 

Flatfish: When you hold a flatfish up to the light you can see through it, which enables you to do an internal examination without cutting it open. On female flatfish, the gonad extends in a dark red, curved wedge which is absent in the male.

Female showing long curved gonad

Male – long gonad is absent

Sharks, skates and rays. Males have external claspers that they use in mating, while in females the cloaca is smooth and claspers are absent.

Male Angel shark – arrows point to claspers

Female Angel shark – claspers are absent

Personal Log

A tropical depression moved through the Gulf yesterday evening, making it too rough and windy to fish. So instead of counting, measuring and loading data into FSCS, my watchmates and I cleaned the lab, secured our gear, and headed up to the lounge to watch Shutter Island on the large-screen TV. Last night my bunk was like a roller coaster, tossing me from side-to-side and head-to-toe as the ship rolled and pitched in the big swells. Today has been a slow day for the scientists on board, waiting for the storm to pass so we can start trawling again, while the crew and officers remain as busy as ever.

Megan Woodward, July 10, 2009

NOAA Teacher at Sea
Megan Woodward 
Onboard NOAA Ship Oscar Dyson
July 1 – 18, 2009

Mission: Bering Sea Acoustic Trawl Survey
Geographical Area: Bering Sea/Dutch Harbor
Date: Tuesday, July 10, 2009

The pollock are carefully loaded onto the table.

The pollock are carefully loaded onto the table.

Weather/Location 
Position: N 56.30.202; W 172.34.37
Air Temp: 7.4 (deg C)
Water Temp: 7.4 (deg C)
Wind Speed: 19 knots
Weather: Overcast

Science and Technology 

Once the fish are onboard a rigorous data collection process begins.  All of the data collected are recorded via instruments linked to a computer network in the fish lab.  Below is a series of photos showing the process used in the fish lab to collect valuable data.

Once the fish are on the table, we carefully look through the fish for any species other than pollock caught in the trawl.  These non-pollock species are sorted into bins and accounted for. The fish are weighed one basket full at a time as they reach the end of the conveyor belt.  Initially, we take a count of how many fish fill one basket.  There is a scale connected to a computer program that records the basket’s weight.

The sorting begins. The pollock are sorted between male and female.

The sorting begins. The pollock are sorted between male and female.

After weighing the pollock, we move on to sorting a sample of approximately 300 fish by sex.  To find the sex of a fish we cut open its belly and look for either male or female reproductive organs. The sexed fish are then placed in the appropriate bin. Next, each pollock from the male/female sort is measured in centimeters.  We use a measuring board linked to a computer that records the size of each fish. There is a small tool in my hand that gets placed at the “v” of the fish tail.  Sensors on the board detect the placement of the measuring wand, and send a length measurement to the computer so it can be recorded.  This program also keeps track of how many fish we measure, so we get an accurate sample count.

The stomach of a pollock is prepared for preservation.

The stomach of a pollock is prepared for preservation.

Several scientists have asked us to collect pollock for various research projects. One project, designed to study the diet of pollock, requires us to sex, measure, weigh and take the stomach of 20 pollock from each haul. A label with all of the information is placed in a bag with the stomach.  They are placed in a freezer for preservation purposes.

Here I am using the measuring board. The stomach of a pollock is prepared for preservation.

Here I am using the measuring board.

We also use a similar process for scientists examining one-year-old pollock. This study asks for the entire fish to be preserved, not a specific organ. In one 12-hour shift there is a maximum of 3 trawls if fish sign is identified in the acoustics lab. Each trawl takes 2 to 3 hours to process. It’s possible another trawl could happen while finishing up the data collection from the previous haul. This makes for a very busy, fish filled shift.

Personal Log 

I was in charge of weighing the fish!

I was in charge of weighing the fish!

Working in the fish lab has provided for a tremendous amount of new learning to take place. I’ve learned to identify species of fish that mix in with pollock (capelin, flatfish, skate and cod), and have seen several crustaceans and jellyfish, too.  All of the measuring technology has been straight forward and user friendly. Sexing the fish has been the most difficult job, but has become easier with practice. Examining the innards to identify male or female reproductive organs seems nearly impossible in the young fish, and it’s not always clear in the older fish.

Today I was in charge of weighing the fish as they came down the conveyor belt. I was certainly mistaken when I thought it would be a simple task. First off, I had to count the fish as they dropped into the basket at a speed faster than I could count. At the same time I had to control the speed of the belt and open the gate so more fish would move down the line.  When the basket was full, I stopped the belt and placed the full (semi-accurately counted) basket on the scale and waited for the scale’s “steady” signal to come on.  Since the boat is constantly in motion the steady light rapidly blinks on and off. It took me three tries before I managed to get the basket weighed.  Meanwhile the rest of the team patiently waited.  Maybe I’ll give it another try tomorrow.

This average sized skate was flapping his wings making him difficult to hold. Look closely at the fish on the conveyor belt and you will see hermit crabs and seastars.

This average sized skate was flapping his wings making him difficult to hold. Look closely at the fish on the conveyor belt and you will see hermit crabs and seastars.

Basketstars were brought up in a bottom trawl. Hermit crabs and snails were also caught in the bottom trawl.

Basketstars were brought up in a bottom trawl.

Hermit crabs and snails were also caught in the bottom trawl.

Hermit crabs and snails were also caught in the trawl.

Animals Seen 

  • Minke Whale
  • Skate
  • Pacific Cod
  • Tanner Crab
  • Snow Crab
  • Basketstar
  • Sturgeon Poacher
  • Snails
  • Hermit Crabs
  • Arrow Tooth Flounder

Megan Woodward, July 5, 2009

NOAA Teacher at Sea
Megan Woodward 
Onboard NOAA Ship Oscar Dyson
July 1 – 18, 2009

Mission: Bering Sea Acoustic Trawl Survey
Geographical Area: Bering Sea/Dutch Harbor
Date: Tuesday, July 5, 2009

Weather/Location 
Position: N 58.37.239; W 171.05.968
Air Temp:  4.5-6.0 (deg C)
Water Temp:  4.94 (deg C)
Wind Speed: 16 knots
Weather: Overcast and rainy

This is the screen I use to get info about our ship’s location.  The little white speck inside the red oval is our ship.

This is the screen I use to get info about our ship’s location. The little white speck inside the red oval is our ship.

Science and Technology Log 

We have been at sea now for almost five days in search of pollock. The fish had not been spotted on the lines we traveled on until today. We had the opportunity for our first pollock trawl around 02:00, and used the Methot net to bring in two zooplankton samples earlier in my shift. This was by far the most action yet.  I was eager and ready to see what the fishing process was all about. This log will focus on the zooplankton samples.

The Methot net was put in the water and lowered to the desired depth determined by watching the location of the acoustic return. After twenty minutes the net was brought back up and the catch was unloaded.  I was expecting a net full of euphausiids, but the critters were actually collected in a small container on the back end of the net.  The catch was brought into the fish lab and dumped into a bucket so we could separate the other organisms caught in the net (9 jellyfish and 23 tiny pollock in this case). Once the other fish had been removed, we took a sample (a ••• cup scoop) to weigh and count the euphausiids in the sample (sample is shown above). The rest of the catch was also weighed. 

There were 543 euphausiids in the scoop. The weight and number help estimate the amount of euphausiids in the entire catch. We repeated this process again a few hours later. The second sample had almost twice as many euphausiids, 13 jellyfish and fewer than 5 pollock.

The survey tech and skilled fishermen lower the Methot net into the water.

The survey tech and skilled fishermen lower the Methot net into the water.

Personal Log 

Until today, the fishing portion of this trip remained a mystery.  However, I was feeling a little sea sick, okay very sea sick, so it was probably a good thing. We encountered some VERY rough seas with sustained winds ranging from 30-40 knots and swells averaging 17 ft. Some of the swells were much larger; one was rumored to be almost 35 ft. high.  Apparently the rough seas are expected to return tonight and tomorrow. My sea legs are securely fastened, so I am ready to take on whatever the sea has to offer.

When we brought in the first haul of pollock last night, my eyes must have looked like they were going to roll out of my head.  I couldn’t believe how many fish were coming across the conveyor belt. This was what I had been waiting for, so I got on my rain gear and started sorting the fish.  Each species was placed into separate crates so a count of all fish caught could be taken.  Of course, pollock made up the majority of the catch.  In the next few weeks, I will become an expert member of the pollock survey team. Everyone on board, both scientists and crew, have been more than willing to answer my

A sample of zooplankton brought up in the Methot net. These are euphausiids, which are also referred to as krill.

A sample of zooplankton brought up in the Methot net. These are euphausiids, which are also referred to as krill.

Getting used to the 16:00-04:00 (4pm4am) shift has been trying.  Today’s shift was the first that didn’t require a nap.  Due to the odd shift hours, I’ve been waking up at 14:00 (2 pm) and going to bed around 05:00 (5 am).  This makes mealtime tricky.  Dinner is served first, then I eat some breakfast in the middle of the night. My body is thoroughly confused. The ship’s cooks are wonderful, and continually provide a stocked mess hall with loads of choices.  I swear the dessert bar is continually whispering my name. I couldn’t ask for a more kind, welcoming group of people to work questions. One part of this adventure I’m looking forward to is getting to know the wide range of characters who make this important research possible.

It was certainly a thrill to see the first whale of the trip. The pod was spotted just off the bow of the ship andlater seen in the distance.

It was certainly a thrill to see the first whale of the trip. The pod was spotted just off the bow of the ship andlater seen in the distance.

Animals Seen 

  • Fin Whale
  • Jelly Fish
  • Flathead Sole
  • Northern Flathead Sole
  • Arrow tooth Flounder
  • Pollock
  • Yellow Irish Lord
  • Euphausiids

New Vocabulary 

Zooplankton– A very small or microscopic animal organisms possessing little or no power of locomotion (can’t move themselves), leaving them to merely drift or float in the water.

Euphausiids (eu·phau·si·id) – A type of zooplankton, also known as krill, are tiny shrimp-like crustaceans that form an important part in the diet of many animals including whales, seals, fishes and birds. These are the main food source for pollock.

Methot Net  – Methot is the name of the man who designed the style of plankton net we used to catch the euphausiids.

One of several jellyfish brought up in the nets. This guy is slimy and heavy, but not a stinger

One of several jellyfish brought up in the nets. This guy is slimy and heavy, but not a stinger