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Step 4 – Eliminate areas outside preferred temperature range

Now take your updated chart and use the Chesapeake Bay Temperature map provided and the temperature information found on the following links to begin shading out areas that are outside avoidance level temperatures for your target fish using the information you gathered in Step 1.

Tips:

  • If the preferred temperature range for your target fish is cooler than existing surface water, look for the coolest water available. During warmer months, in nearshore areas, waters near underwater grass beds are often cooler than surrounding waters due to the shading effects from the underwater grasses. In addition, during warmer months, in deeper waters, the coolest water is often found at deeper depths.
  • If the preferred temperature range for your target fish is warmer than existing surface waters, look for the warmest water available. During cooler months in nearshore areas, waters near warm-water discharges often draw Bay fish. In addition, during cooler months in deeper waters, the warmest water is often found at deeper depths. Several types of bay fish will overwinter in these areas if there is adequate protection from current.
  • An event called the "Rockfish Squeeze" occurs in the summer when rockfish (striped bass) try to move to deeper water in search of cooler water, but are prevented by poorly oxygenated waters. Rockfish end up being squeezed into a small layer of barely suitable water at the extremes of their maximum temperature tolerance (84°F) and their minimum dissolved oxygen requirements (~3 mg/L.)
  • General temperature patterns will remain stable unless there are prolonged periods of substantial rain (cools water) or extreme heat (warms water.)
  • Note: For your convenience, we have included temperature information for some popular Bay gamefish.

Links:

  1. Chesapeake Bay Temperature map(view in Step 4 on main page) This composite map includes temperature data over all Maryland Bay waters from surface to bottom and will provide a good overview of general temperature conditions.

  2. Eyes on the Bay: Current vs. historical temperature comparison
    This site will help you determine if the water is much warmer or colder than normal in your general fishing area. When water temperatures are warm, cooler than normal temperatures may increase activity of gamefish. When water temperatures are cool, warmer than normal temperatures may also increase gamefish activity.

  3. Eyes on the Bay: Finding depths with the best combination of temperature and oxygen for your target fish
    This site will help you identify where to find the depth of the best water temperature (and adequate oxygen levels) for your target fish. During warmer months, the deeper waters will often be cooler than surface waters. During the cooler months, the deeper waters will often be warmer than surface waters. In shallower locations and deeper locations during spring and fall turnovers, the water temperature will often be uniform from surface to bottom. So depending on the conditions and time of year, your target fish may move up or down, or may even be able to move throughout the entire water column to find their preferred water temperature.
    white circle icon Surface water temp = Max Fishing Depth water temp Water column is well mixed, water temperature is uniform from surface waters down to maximum fishing depth or DO NOT FISH BELOW THIS DEPTH layer.
    red circle icon Surface water temp warmer than Max Fishing Depth water temp Surface waters are at least 2°F warmer than water temperatures at maximum fishing depth or DO NOT FISH BELOW THIS DEPTH layer. Note: These cooler, oxygenated, deeper waters can be key locations during warmer months.
    blue circle icon Surface water temp colder than Max Fishing Depth water temp Surface waters are at least 2°F cooler than water temperatures at maximum fishing depth or DO NOT FISH BELOW THIS DEPTH layer. Note: These warmer, oxygenated, deeper waters can be key locations during cooler months.

  4. Eyes on the Bay: Temperature monitoring stations
    This site will help you determine the specific temperature at the stations nearest to your general fishing area.
       - Use the "Filter station" dropdown to select continuous monitoring, long-term monitoring and partners/other data providers.
       - The long-term monitoring sites (red square red squares) are generally located in deep water and can be selected and will show you how current year's results compare to the long-term average.
       - 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 temperature changes that occur in response to local rainfall (cools water) or shallow, poorly flushed areas (warms water). Temperature 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 water temperature conditions at real or near real time. Because these sites collect data every 15 minutes you are able to see the rapid temperature changes that occur in response to local rainfall (cools water) or shallow, poorly flushed areas (warms water).

  5. Chesapeake Observing System (NOAA CBOS) Temperature monitoring stations
    This real-time site will help you verify your temperature conditions at several mainbay/main river sites. Select the station nearest to your general fishing location, and select "Water Temperature." For convenience, you can plot out temperature information from 1 to 30 day periods.

Now that you have eliminated areas that are outside avoidance level temperatures on your chart, you are ready to move to: Step 5 – Eliminate areas with poor water clarity

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