Mission: Alaska Walleye Pollock Survey
Geographical Area: Gulf of Alaska
Date: July 6th, 2013
Location Data from the Bridge:
Latitude: 55.29.300 N
Longitude: 156.25.200 W
Ship speed: 10.7 kn
Weather Data from the Bridge:
Air temperature: 8.6 degrees Centigrade
Surface water temperature: 8.6 degrees Centigrade
Wind speed: 14 kn
Wind direction: 210 degrees
Barometric pressure: 1008.5 mb
Science and Technology Log:
The Oscar Dyson is equipped with several labs to accommodate the researchers on board. In this blog post I will describe to you what is happening in the wet/fish lab. This is where I have experienced quite a bit of hands-on data collection.
After a trawl, the crew dumps the load of fish into a bin. Inside the lab we can raise or lower this bin to control the amount of fish coming onto a conveyor belt. Once the fish are on the belt the scientists decide how they will be separated. We separate the pollock according to age into baskets. They are categorized by size; under 20 cm (age 1), under 30 cm (age 2), and any larger than 30 cm
At this time we also pull out any other sea creatures that are not pollock. So far we have pulled up quite a few jelly fish, la lumpsucker, shrimp, squid, eulachon, and capelin. These are also weighed, measured, and in some cases frozen per request of scientists not currently on board.
After organizing the pollock into appropriate age groups, we then measure and record their weight in bulk. Scientists are using a scale attached to a touch screen computer with a program called CLAMS to record this information. The pollock are then dumped into a stainless steel bin where their sex will be determined. In order to do this the fish must be cut open to look for “boy parts, or girl parts”. After the pollock are separated into female and male bins we begin to measure their length.
The tool used to measure length is called the Ichthystick. This tool is connected to the CLAMS computer system. The fish is placed on the Ichthystick and a pointer with a magnet in it is placed at the tail end of the fish. There are three different types of length measurement that can be done: fork length, standard length, and total length. When the magnetic pointer touches the Ichthystick it senses that length and sends the information to the CLAMS computer system.
One of these bins of fish is placed aside for individual weighing, length measurements, and removal of otoliths. You may recall that I mentioned otoliths in the last blog post. These ear bones are sent to a lab and analyzed to determine the age of each of these individually measured fish. The Alaska Fisheries Science Center has created a demonstration program where you can try to determine the age of different types of fish by looking at their otoliths. Click here to try it yourself! (I will add hyperlink to: http://www.afsc.noaa.gov/refm/age/interactive.htm)
One afternoon while waiting for the fishermen to bring up the trawl net, I watched a group of porpoises swimming behind the ship. Another day I was able to see whales from up on the bridge. These were pretty far out and required binoculars to see any detail. I observed many spouts, saw one breach, and some flukes as well.
There is quite a bit of downtime for me on the ship while I am waiting in between trawls. I get to read a lot and watch movies in my free time. I have had the opportunity to talk with different members of the crew and learn about their roles a bit. The chief engineer gave me a tour of the engine rooms (more about this with pictures in a future post.)
The 4th of July fireworks show on the Oscar Dyson was like no others I have ever experienced. Two of our crew, Ben & Brian, dressed in official fire gear shot expired flares off the ship into the sea. America themed music was played over the PA system. I have attached a video of our fireworks display. Happy Independence Day everyone!