NOAA Teacher at Sea
Jillian Worssam
Aboard NOAA Ship Miller Freeman
July 5 – August 1, 2004
Day: Five
Saturday July 10th, 2004 1:20
Longitude: 59° 50 Sea Wave Height: 1-2′
Latitude: 173° 14 Swell Wave Height: 0′
Visibility: 2.1miles fog Sea Water Temperature: 9.4C
Wind Direction: 121.6 Barometric Pressure: 1019 high pressure
Wind Speed: 11.3 kts Cloud Cover: complete 100%
Haul Data – Methot
Depth of haul: 20 meters
Temperature at depth: 7° C approximate
Species breakdown: walleye pollock year 0, Amphipod- type of crustacean, Chrysora jellyfish
Science and Technology Log:
The Methot haul is when the nets are set out, but at the end there is a cylindrical tube of PVC. It is this tube in which the sample will be taken. Holes are drilled in the side to let the water run through, but there is a mesh screen which prevents the specimens from escape. The purpose of the Methot trawl is to collect younger samples of fish, and as the younger pollock tend to stay higher in the water, and this device is perfect for sampling. Most of the pollock were year zero meaning that they spawned this past April. There is also a relationship between the juvenile pollock and the jellyfish as the Jellies (common term) provide shelter for the young fish. Walleye pollock are cannibalistic and will eat younger smaller fish that could well be their own children.
One of the scientists on board Taina Honkalehton has just returned from Tasmania where she was contracted by the Australian government to study orange roughy, a species that has been over harvested that they are now trying to save as a viable harvest species. Pollock on the other had is a well managed species, where at this time approximately 20% of the population is being utilized for commercial ventures. Pollock are the fish of fish sticks, a very important economic product on a global scale, with pollock as the largest single species fishery in the world making oceanic ecosystem management very important. Approximately 1.8 million tons of Pollock are harvested annually. Part of the management plan for pollock is based in part to their relationship to the stellar sea lion. As an endangered species management needs to look at fish harvesting and see if there is a relationship between the decline of the sea lion and changes in fish numbers.
Personal Log:
Running late tonight, having too much fun gutting fish, measuring jelly fish and cleaning. I have often wondered the purpose of jelly fish. As an Easterner by birth my only experience has been the Portuguese Man of War, the stinging variety that invariably closed our local beach. The jellyfish we have been seeing not only provide habitat for many other aquatic species, but that are also a nutritious food source. Monterey Bay Aquarium has a wonderful display of jelly fish. An amazing species, so beautiful in their basic simplicity.
I promised I would talk about the spinner, which no one has been able to give me a scientific designation for. This amazing piece of technology is a circular window approximately two feet in diameter, the ships windshield. During winter months the entire window of the bridge often freezes up, and this device, through the use of centrifugal motion, manages to keep an area clear for viewing. The glass of the spinner, you guessed it, spins at a very fast rate thus keeping the viewing surface clear. It is a funky tool, and so far my favorite on the bridge.