User Defined Swim Speeds Tab

The User Defined Swim Speeds tab allows you to enter and modify swim capabilities.

Note: When data from the Literature Swim Speeds tab is saved as a Custom Setting it will be saved as a User Defined Swim Speed.

Fish Length:

Enter the Total Length of the fish, if only fork length is available, you may use the Fish Length Conversion Table to estimate total length.  The difference between fork and total length is likely only significant for smaller fishes.

Prolonged / Use Both / Burst:

Select the Swim Mode to be used in the model run.  Swimming performance is classified into three major categories:  sustained, prolonged and burst. FishXing uses only prolonged and burst. If either Burst or Prolonged are selected, the swimming speeds associated with the category will be exclusively used through out the culvert.  If Use Both is selected FishXing allows the fish to switch between prolonged and burst speeds as needed.  The fish are able to maintain burst or prolonged speeds for the duration of time entered in the Time to Exhaustion field.

Choosing Use Both can be useful when water velocities in the barrel of the culvert are low enough for passage in the prolonged swim mode, but the velocities within the inlet and outlet zones of the culvert are fast enough to require swimming in the burst mode.

Prolonged Speed:

Prolonged swim speeds usually can be maintained by the fish for 20 seconds to 200 minutes before ending in fatigue.  Most fish passage velocity criteria are based on the prolonged swim speed of the target fish.

Burst Speed:

Burst speeds are the highest speeds attainable by the fish and can be maintained for only short periods of time, usually less than 20 seconds.  Fish may need to use burst speeds to swim through areas of high velocities in the culvert.

Time to Exhaustion:

Time to Exhaustion is the period of time that a fish can maintain the swim speed selected before becoming exhausted.  Times typically range between 20 seconds to 200 minutes for prolonged swimming speeds and 1 to 20 seconds for burst swimming speeds.

Notes and References:

This Notes area is a text box available for entering comments or referencing the source of the inputted swim speeds.

Min Depth:

The minimum water depth is the depth of flow within the crossing required for successful fish passage.  A depth barrier is reported if the calculated water depth is below the specified Min Depth. The Min Depth should be sufficient to fully submerge the species being modeled because fish that are not fully submerged cannot obtain optimal swimming performance.  If the Min Depth is less than the Fish Body Depth reported in the Notes (green text box), a warning will be issued.  See Water Depth for Swimming for a discussion on the limitations of swim speed equations when a fish is not fully submerged.

Outlet Criteria:

From the dropdown select the method you wish to use for analyzing fish passage conditions at the culvert outlet. The two options are:

Max Leap Speed – Enter the maximum speed the fish can leap out of the water when attempting to leap into the culvert outlet.  This speed is often at the upper end of the fish’s burst swimming ability.  Leaping calculations only occur when the fish is unable to swim into the culvert.  See Leaping Calculations and Entering the Culvert: Outlet Leap or Swim or an explanation of how FishXing determines when the fish can swim into a culvert rather than leap.

Max Outlet Drop – Enter the maximum allowable drop in water surface at the outlet.  FishXing will identify a drop barrier when the outlet drop is greater than the specified Max Outlet Drop.  The outlet drop is measured between the water surface in the outlet and the tailwater surface.  Unlike the leaping calculations, the outlet drop criteria apply even when the tailwater elevation is above the culvert bottom.  See Outlet Drop Criteria for a discussion on how and when the drop is calculated.