Bathymetric Mapping

The bottom of the ocean is every bit as complex as the topography of dry land.  And, just like on land, different fish species associate with different benthic, or seafloor, structures.  Bathymetry, or the mapping of the ocean floor, gives fishermen the tools to visualize these benthic structures. 

More information about this work, as well as information for fishermen using Nobeltec Catch and participating in data collection, is provided below. 

About Bathymetric Mapping

Rockfish Bycatch

Collecting Bathymetric Data

                  Copying Files Using Nobeltec 

                  Copying Files Using Catch

                  Using ALFA Raster Charts

 

About Bathymetric Mapping

 

Members of ALFA’s Fishery Conservation Network collaborate to create detailed bathymetric maps.  Using a software program called Nobletec Catch, FCN members collect seafloor bathymetry data.  At the end of each fishing season, FCN members share this data with ALFA.  ALFA combines the files it into one database, and provides the enhanced maps back to fishermen. These maps help fishermen catch their target species efficiently while controlling catch of non-target species, such as rockfish, and avoid the high relief areas that host sensitive benthic species, such as corals and sponge.  This prevents overharvest of long-lived and tightly managed rockfish species, protects important habitat, and makes our small boat fishermen more competitive.

       On the left is a standard NOA chart, on the right is an ALFA Bathy chart with the colors indicating seafloor bathymetry. 

       On the left is a standard NOA chart, on the right is an ALFA Bathy chart with the colors indicating seafloor bathymetry. 

ALFA has also worked with NOAA and ADFG to translate multi-beam bathymetry data into a format compatible with the programs and electronics being used by small boat fishermen. This high-resolution data is quilted together with the fleet generated bathymetric data to create high-resolution seafloor maps at a price small boat fishermen can afford.  ALFA has also shared these enhanced bathymetry maps with the Alaska Department of Fish & Game to help them plan their rockfish surveys to improve stock assessment. 

 

Rockfish bycatch

Rockfish bycatch control was the Fishery Conservation Network’s (FCN) first project. In 2008, the Alaska Board of Fisheries challenged both commercial and charter halibut fishermen to control their bycatch of rockfish in the halibut fishery because the sectors were exceeding rockfish quotas.  ALFA took this challenge to heart and launched the FCN rockfish bycatch initiative.

Participating FCN members collect catch and rockfish bycatch rate data in the halibut and sablefish target fisheries.  This data is recorded by set quadrant and provided to ALFA after each fishing trip.  Set date is kept confidential, but compiled with reports from other vessels to identify rockfish bycatch hot spots.  Individual sets are also color coded to reflect bycatch rates by quadrant, then printed over seafloor bathymetry maps that allow fishermen to see the connection between high relief terrain, such as reefs and pinnacles, and increased rockfish bycatch rates.  Using these maps, fishermen can adjust sets to efficiently harvest target species while avoiding reefs and controlling bycatch rates to permissible levels.

In the first two years of the rockfish bycatch network, participating fishermen reduced bycatch rates in the halibut fishery by 20 percent and bycatch rates in the sablefish fishery by 7%.  Since then, bycatch rates in both the halibut and the sablefish fisheries have remained below 2009 levels and within the levels permitted in the longline fisheries.

ALFAs rockfish bycatch network protects long-lived rockfish stocks by preventing overharvest; the network also ensures halibut fisheries are not confined by rockfish overfishing.  By giving fishermen the tools to increase fishing efficiency while controlling bycatch rates ALFAs FCN combines scientific precision with the experiential expertise of fishermen to enhance fisheries management.  

ALFA is now working with Nobeltec to translate existing maps into an interactive base layer that allows FCN members to continue to improve the charts with additional data on every trip.  ALFA will also continue to enhance maps with additional multi-beam data as NOAA and ADFG survey new areas.

Not an FCN member yet?  Join today! 

 

Collecting bathymetric Data

How to copy files to your jump drive using Nobeltec VNS (9,10,11)

) Insert ALFA-supplied thumb drive
2) Right click and create a new folder - Name the folder "2013 Bathy Data" 
3) In your computer's Start Menu:
4) Look under Computer> C Drive> Program Files> Nobeltec> Visual Series
5) Copy folder titled "Bathy Recorder Data" to ALFA-supplied thumb drive folder "2013 Bathy Data"


(The path and folder names differ depending on your operating system. If the above does not work, a simple search of "2013 BTH files" should bring up the correct files. You can then copy and paste those files to the thumb drive folder.)

If you have any problems at all, please don't hesitate to call us at the office. Our number is 747-3400.

How to copy files to your jump drive using Catch 

1) Open Catch
2) Insert an ALFA thumb drive with a folder called "backup" on the root directory. That is, the folder labeled "backup" cannot be located within another folder. If it is missing, create a new folder labeled "backup." There can be no deviation in this name. It must simply be "backup." We will add the year when we pull that data off your drive.
3) Catch will offer to backup all. Click 'yes' (then click OK).

ALFA Raster Charts

Installing
·         Open Nobeltec V8 or V9
·         From Menu select Tools and Permit and Unlock Codes
·         Insert ALFA CD. (If you insert CD first, Nobeltec may or may not auto-search and install charts.)
·         From drop-down menu, select Raster and Photo Charts
·         Click Browse
·         You are looking for your CD drive, which is usually D:\ or E:\  The path name for the charts is d:\raster multibeams with overlays. Open that folder, click Select All
·         In the lower left of this window, click the bullet for Copy Charts to. This will copy the charts from your CD to the default chart folder on your computer.
·         Click Done and the system will install and copy the charts fo

How to Use Raster Charts
If you normally use vector charts, you will need to click the raster chart icon on the menu bar. Do not attempt to click this button if your Nobeltec 3D charts are open. It will lock your computer up in an attempt to overlay charts on 3D images for you.

Click the Tile Windows Vertically button. This will duplicate the chart on the screen into two even screens. From here you can operate both screens like you normally do. *Note that the cursor in the active screen shows up as a “crosshairs” in the inactive screen. Each screen can be zoomed, set to autoscroll, and scrolled on its own.

Much of the manipulation of these screens is going to be adding and removing charts from the quilt. If you right click on any active chart, it will give you the option to Remove <this charts> from Quilt. This does not uninstall the charts. If you want to show a chart in the quilt, right click Other Charts, and select the chart you want to see.

Click Here for Instructions on How to Display Raster Charts on Dual Screens

How to Find Files
Everything is recorded by the software (unless it has been manually erased), and is stored in:

  • Computer (C:),
  • ProgramData, you have to unhide the file by clicking on:
  • organize when you are in C:
  • “folders and search options”,
  • “view” tab,
  •  select “show hidden files and folders”);
  • Nobeltec TZ,
  • Data,
  • Then select the tracks file

Banner image credit Caroline Lester