Tag: CamTrawl

Posted on

Amie Ell: A Whale of Tale, July 13, 2013

NOAA Teacher at Sea
Amie Ell
Aboard NOAA Ship Oscar Dyson (NOAA Ship Tracker)
July 7 – July 11, 2013

Mission: Alaska Walleye Pollock Survey
Geographical Area: Gulf of Alaska
Date: July 13, 2013

Location Data from the Bridge:
Latitude: 57.21N
Longitude: 152.32 W
Ship speed:   10.7 kn

Weather Data from the Bridge:
Air temperature: 11 degrees centigrade
Surface water temperature: 11 degrees Centigrade
Wind speed:  7.14 kn
Wind direction: 90 degrees
Barometric pressure: 1018 mb

Science and Technology Log:

The CamTrawl being attached to the net.
The CamTrawl being attached to the net.

The scientists on the Oscar Dyson are using several different types of cameras and sensors.  I have already mentioned the CamTrawl.  This camera is attached to the trawl net and takes pictures as the net is being dragged behind the ship.  The pictures are time stamped.  These pictures help to identify at what time and depth things were entering the net.  This is very helpful if you have a haul with a variety of different fish.  Also attached to the net is the FS-70 Netsond sensor, also known as the third wire.

A CamTrawl Picture with pollock and capelin.
A CamTrawl Picture with pollock and capelin.

This third wire uses sound and its echo to see what is entering the net.  One more sensor attached to the net reads temperature and depth this is the SeaBird Electronics SBE-39 Bathythermograph.

Preparing to lower the Drop Cam.
Preparing to lower the Drop Cam.
From left to right: DropCam, winch, CTD (Conductivity, Temperature, Depth),
From left to right: DropCam, winch, CTD (Conductivity, Temperature, Depth),

Sometimes sensors and cameras are dropped from the side of the ship.  These are not attached to a net.  Instead, these are on frames that are dropped over the side and lowered using thick cable wire on a winch.  The CTD sensor measures water conductivity, temperature, and depth.

The Drop Camera also is dropped from the side of the ship and lowered using a winch.  This also has a depth sensor and takes time stamped pictures.  This device can help scientists identify fish present in areas that they are not able to trawl in.

An octopus captured by the DropCam.
An octopus captured by the DropCam.

The compilation of information gathered from these sensors, cameras, and haul data will help scientists get a good picture of what type and how many fish are present in different areas around Alaska and in varying ocean conditions.  The analysis of this data will be used to help determine the quota for commercial fishermen looking for the Alaskan walleye pollock in different areas.

There are sensors on the hull of the ship that are always gathering information.  On the NOAA website Ship Tracker you can see some of this information in real time.

Depths recorded and graphed for this trip.
Depths recorded and graphed for this trip.
A flatfish captured by the DropCam
A flatfish captured by the DropCam

Personal Log

Yesterday was an excellent day for whale watching.  We spent our afternoon and evening surrounded by a pod of Humpback whales.  At times they were so close that I could hear them breathing.  They were much closer and more plentiful than the first whale sighting.  Last night in the mess hall I got up to look out the porthole (window) and a whale came up less than 50 feet from me.  It was amazing!

We continue to trawl pulling up on average 2 to 3 hauls an evening.  In our hauls the majority of the fish are pollock.  This week I have also seen, more capelin, rock fish, and lumpsuckers.  We have also pulled up dog salmon, arrow tooth flat fish, krill, cod, and a spiny lumpsucker.

A sunset trawl in progress
A sunset trawl in progress
From bottom: Dog Salmon, Arrow Tooth, Pacific Ocean Perch (POP)
From bottom: Dog Salmon, Arrow Tooth, Pacific Ocean Perch (POP)

I was given a tour of the engine rooms below by the Chief Engineer.  It was very loud.  There is a lot of machinery on board to make the ship self-sustainable while at sea.  One of the machines is called the “water maker”.  This takes salt water and heats it to 140 degrees Fahrenheit.  The machine then captures the steam, leaving behind salt and other non desired items in the water.  The steam is then condensed to make all for the fresh water for the ship.

Water Maker distills salt water to make fresh
Water Maker distills salt water to make fresh
Posted on

Amie Ell: Deadman’s Bay, July 11, 2013

NOAA Teacher at Sea
Amie Ell
Aboard NOAA Ship Oscar Dyson (NOAA Ship Tracker)
July 7 – July 11, 2013

Mission: Alaska Walleye Pollock Survey
Geographical Area: Gulf of Alaska
Date: July 11th, 2013

Location Data from the Bridge:
Latitude: 56.56 N
Longitude: 152.74 W
Ship speed:   11.3 kn

Weather Data from the Bridge:
Air temperature: 10.7 degrees Centigrade
Surface water temperature: 8.6 degrees Centigrade
Wind speed:  18 kn
Wind direction: 250 degrees
Barometric pressure: 1016 mb

Science and Technology Log:

Nets on Spools
Nets on Spools
OLYMPUS DIGITAL CAMERA
Full net on deck
OLYMPUS DIGITAL CAMERA
Pollock from a bottom trawl

So now that you know what we do with the fish after they are caught, let’s go back and see how the fishermen trawl.  There are two large nets at the stern of the ship.  Today we used both nets for the first time.  The scientists, crew, and fishermen all work together to catch the fish.  In the acoustics lab Paul is reviewing and scrutinizing the data he receives from the echo locators mounted on the hull of the ship.  There are many factors he must evaluate in order to have a good trawl.  There are places in our area that have been marked as “untrawlable”.  This is usually due to a sea floor that is rocky.  Trawling in these places may ruin the nets.  We have completed at least one trawl a day since we have been out to sea.  Today we completed two during my watch.  The first was with a larger net and was not sent all the way to the bottom.  The second trawl was sent to the bottom with a smaller net.  The bottom trawl brought up the largest pollock I have seen so far.  The longest pollock was 75 cm.  We also brought up a salmon, cod,   rock fish, and a whole lot of herring.

Crane lifting the net to be dumped into the bin.
Crane lifting the net to be dumped into the bin.
OLYMPUS DIGITAL CAMERA
The CamTrawl being removed after a trawl.

The nets are both on large spools and are released or returned with the help of a very large winch.  Before the net is released into the water the CamTrawl is attached to it.  This is a camera that takes pictures that help the scientists see at what point in the trawl fish were entering the net.

Example photo from the CamTrawl. A Salmon Shark caught on the first leg.
Example photo from the CamTrawl. A Salmon Shark caught on the first leg.

The time that the net is in the water depends on the information about the amount of fish coming from the acoustics lab.  Scientists watch the echo information to determine how much time the net should be in the water to catch enough fish to sample.  We must have at least 300 pollock to make a complete survey.

The fishermen bring the nets back to the trawl deck and wind them back onto the spools.  They then will use a crane to lift the catch and dump it into a bin.  From the fish lab we can lift this bin to dump the fish onto the conveyor belt.

Personal Log

Me in my survival suit
Me in my survival suit
Entering Deadman's Bay
Entering Deadman’s Bay

On Monday, we had our weekly fire and abandon ship drills.  After the drills I practiced putting on my survival suit.  This suit is designed to keep you afloat and warm in the event that you have to go into the water.

Deadman's Bay
Deadman’s Bay

On Tuesday, we surveyed up into Deadman’s Bay.  It was a beautiful sun shiny day and the scenery was amazing.  We were very close to the shore on both sides.  I sat out on the trawl deck and scanned the hillsides with my binoculars.  I was told that it is common to see bears here, but I did not see any.