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Step 3 – Eliminate poorly oxygenated areas

Now take your updated chart and use the Chesapeake Bay Dissolved Oxygen map provided and the oxygen information found on the following links to begin shading out areas that do not have adequate oxygen for your target fish using the information you gathered in Step 1.


  • Oxygen Pattern Stability (Eyes on the Bay) - General oxygen patterns will remain stable unless there are prolonged periods of high winds (increases oxygen), extreme heat (decreases oxygen), or a large algal bloom (decreases oxygen at night or when decomposing).
  • Avoid areas with oxygen levels below 3 mg/L.
  • Areas with large amounts of submerged aquatic vegetation or algal blooms typically have high oxygen levels during the day, and very low oxygen at night.
  • Oxygen levels are typically higher during the day than at night.
  • Note: For your convenience, we have included oxygen preferences for some popular Chesapeake Bay gamefish.


  1. Chesapeake Bay Oxygen map (Eyes on the Bay)(view in Step 3 on main page)
    This composite map includes oxygen data over all Maryland Chesapeake Bay waters from surface to bottom and will provide a good overview of general conditions.
       - IMPORTANT: Pay special attention to map areas that have oxygen levels below 3 mg/L. Below this depth there won't be adequate oxygen for Chesapeake Bay fish. Eliminate these areas on your map. If schooling fish are present in the general area, they will be at a shallower depth.

  2. 'Don't Fish Below This Depth' Map (Eyes on the Bay)
    This map identifies the depth at which oxygen levels are unsuitable for most Chesapeake Bay gamefish (~3 mg/L.) DO NOT FISH BELOW THIS DEPTH! The monitoring stations are displayed on a nautical chart to help you visualize the layers of poorly oxygenated waters in relation to the bottom contour. If you click on a station on the map a plot of oxygen by depth will appear. This feature will help you determine the depths where oxygen is most available. Fish in water depths where oxygen is above the 3 mg/L threshold.

  3. Oxygen monitoring stations (Eyes on the Bay)
    This site will help you determine the oxygen conditions at the stations nearest to your general fishing area.
       - Use the "Filter station" dropdown to select continuous monitoring, long-term monitoring, and/or partners/other data providers.
       - The long-term monitoring sites (red square red squares) are generally located in deep water. When a station is selected you can see a chart of how current year's bottom oxygen levels compare to the long-term average (1985-2022).
       - The continuous monitoring sites (orange circle orange and light green circle light green circles) are generally located in shallow waters and show oxygen conditions at real or near real time. Because these sites collect data every 15 minutes you are able to see the changing daily oxygen conditions throughout the entire day. Oxygen data can be plotted numerous ways.
       - The Partners/Other Data Providers sites (orange cross orange and yellow crosses yellow crosses) are additional sites that show oxygen conditions at real or near real time. Because these sites collect data every 15 minutes you are able to see the rapid oxygen changes that occur throughout the day.
Now that you have eliminated areas that don't have adequate oxygen on your chart, you are ready to move to: Step 4 – Eliminate areas outside preferred temperature range
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