Example of conversions based on morphometric data:

In this example, we will use humpback chub, Gila cypha. These conversion factors are only valid for fish that have achieved their adult body form; very young fish have different body morphologies. Notice that the conversion factors are dimensionless so you can use any units of measure (Examples: feet, inches, centimeters).

Excerpt from the Morphometric Data Table:

 Common name Family Genus Species BD/TL TL/SL TL/FL broad whitefish Salmonidae Coregonus nasus 0.232 1.165 1.099 humpback chub Cyprinidae Gila cypha 0.224 1.252 1.134 humpback whitefish Salmonidae Coregonus pidschian 0.196 1.142 1.078 inconnu Salmonidae Stenodus leucichthys 0.174 1.146 1.080 lake sturgeon Acipenseridae Acipenser fulvescens 0.118 1.186 1.096

Where:   BD = Body Depth,  TL = Total Length,  SL = Standard Length,  FL = Fork Length

1.       There are three possibilities:

a.       If you need body depth and you have total length, then use the column BD/TL (body depth/total length) and the row - humpback chub = 0.224.

b.       If you have fork length and you need total length, then use the column TL/FL (total length/fork length) and the humbback chub row = 1.134.

c.       If you have standard length and you need total length, then use the column SL/TL (total length/standard length) and the humpback chub row = 1.252.

2.       Multiply the length you have by the conversion factor as follows.

a.       For a humpback chub with a total length of 8.5 inches to estimate body depth:

BD/TL x TL = BD

0.224 x 8.5 inches = 1.9 inches body depth

b.     For a humpback chub with a fork length of 21.6 centimeters to estimate total length:

TL/FL x FL = TL

1.134 x 21.6 cm = 24.5 cm total length

c.       For a humpback chum with a standard length of 203 millimeters:

SL/FL x SL = TL

1.252 x 203 mm = 254.2 mm total length

See an illustration of fish length measurement.