by Wyatt Fournier, NOAA Fisheries, on the Northwest Explorer
Okay, now that the lead scientists are finally off the boat, it’s time to get some work done! I have come aboard to relieve Jamal and have brought two fresh science crew members. Mike Neary is our seabird and marine mammal observer and joins us for a second survey year. Also joining us is Liz Cote, a seasoned biological technician in the Fisheries Ecology, Diet and Zooplankton Lab at our NOAA facility in Juneau.
We continue the survey by occupying stations on the Southeast Gulf of Alaska grid. The difference between this year’s survey and the 2011 effort is that we have extended our survey to reach 80 miles offshore, compared to just 30 miles last year (see map below).! At these offshore stations we hope to encounter mesoscale eddies (swirls of water between about 10 and 500 km in diameter that can persist for periods of days to months). These eddies are thought to contribute to the shelf-slope exchange of nutrients and plankton, enhancing biological production. This feature has the potential to influence the larval fish that our study focuses on: rockfish, sablefish, pollock, Pacific cod, and arrowtooth flounder.
As we did last year, we will be collecting samples from three different platforms: the CTD (Conductivity, Temperature, Depth)/water sampler, zooplankton bongo nets, and a surface trawl. The CTD/Water sampler (pictured with University of Alaska Fairbanks graduate student Sterling Gaulrich) is dropped 200 meters below the surface to record levels of salinity, temperature, oxygen, turbidity, fluorescence, and photosynthetically active radiation. Upon its retrieve water is sampled at eight depths, later to be analyzed for nutrients and chlorophyll. The bongo nets are named after the musical instrument and consist of a pair of rings that hold a fine mesh net to collect zooplankton from the water column. This device is difficult to deploy, and I’m sure some photos will make it onto the blog this summer. Finally, we have our surface trawl that fishes a width up to 50 meters and a depth of 40 meters during our 30 minute haul.
CTD and East Master Grid