It's all the details of the navigation charts….
NOAA’s Mark Zimmerman is making some detailed maps with antique information that turns out to provide even more detail about the bottom of the Gulf of Alaska – helpful stuff to fisheries managers and researchers.
When the National Oceanic Surveys (NOS) conducted surveys of the bottom of the Gulf of Alaska almost a century ago, the information was used to create the marine navigation charts that we all use on the water. However, when creating the navigation chart, the NOS used only about 1% of the information that was collected from the bottom of the ocean. When NOS digitized the original paper surveys, they left out a lot of the details. Now Mark Zimmerman’s team at NOAA is going back to those paper charts and collecting the details.
“It’s like when we drive our car on a road there are signs that tell us when to stop, where the cross walks are and when to slow down, “says Zimmerman, the NOAA “ The maps we are making now,” says Zimmerman, “tell us where the potholes are.” These new maps have far more details than navigation charts. The old paper surveys show where all the bumps and dips are on the ocean floor, for example, and those bumps are dips are fish habitat. When NOAA surveys the bottom of the ocean for bottom dwelling fish its useful to know when the bottom is going to be too steep or too rough to sample using a bottom trawl and where other methods can be employed to count fish.
For the Gulf of Alaska Integrated Ecosystem Project, these new charts are used to help look at habitat where juvenile fish may be hanging out and when Zimmerman combines his NOS “antique chart” data with GIS topographical information from topo charts he can calculate a whole new set of useful information about marine habitat in the bays and inlets of the Gulf of Alaska. He can calculate how much volume of water there is in a bay, or how much area is covered by kelp beds or rocky reefs. His chart work is being used by NOAA scientists Kalei Shotwell and Jodi Pirtle to make predictive models for where the five species of commercially important groundfish may be found. Go here for more information!
http://www.afsc.noaa.gov/RACE/groundfish/Bathymetry/CentralGOA_1.htm
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