Parameters for all known standard weight equations.
A data frame with observations on the following 13 variables:
Species name.
Units of measurements. Metric
uses lengths in mm and weight in grams. English
uses lengths in inches and weight in pounds.
Type of equation (linear
or quadratic
).
Reference quartile (75
, 50
, or 25
).
The type of length measurement used -- total length (TL
) or fork length (FL
).
The type of method used to derive the equation (RLP
,EmP
, or Other
).
Minimum total length (mm or in, depending on units
) for which the equation should be applied.
Maximum total length (mm or in, depending on units
) for which the equation should be applied.
The intercept for the model.
The slope for the linear models or the linear coefficient for the quadratic equation.
The quadratic coefficient in the quadratic equations.
Source of the equation. These match the sources given in Neumann et al. 2012.
Comments about use of equation.
Most of these equations can be found in Neumann, R.M., C.S. Guy, and D.W. Willis. 2012. Length, Weight, and Associated Indices. Chapter 14 in Zale, A.V., D.L. Parrish, and T.M. Sutton, editors. Fisheries Techniques. American Fisheries Society, Bethesda, MD.
Some species were not in Neumann et al (2012) and are noted as such in the comments
variable.
The minimum TL for the English units were derived by rounding the converted minimum TL for the metric units to what seemed like common units (inches, half inches, or quarter inches).
Relative weight
Standard weight
Condition
8-Condition.
Ogle, D.H. 2016. Introductory Fisheries Analyses with R. Chapman & Hall/CRC, Boca Raton, FL.
str(WSlit)
#> 'data.frame': 201 obs. of 13 variables:
#> $ species: chr "Aegean Chub" "African Sharptooth Catfish" "Alabama Bass" "Ankara Nase" ...
#> $ units : chr "metric" "metric" "metric" "metric" ...
#> $ type : chr "quadratic" "quadratic" "linear" "quadratic" ...
#> $ ref : int 75 75 75 75 75 75 50 75 75 25 ...
#> $ measure: chr "TL" "TL" "TL" "TL" ...
#> $ method : chr "EmP" "EmP" "RLP" "EmP" ...
#> $ min.len: num 70 180 100 70 150 150 160 6 150 70 ...
#> $ max.len: num 220 450 NA 240 NA NA NA NA NA 390 ...
#> $ int : num -3.8 -3.67 -5.6 -10.02 -5.24 ...
#> $ slope : num 1.78 1.88 3.29 7.4 3.08 ...
#> $ quad : num 0.329 0.209 NA -0.971 NA ...
#> $ source : chr "Giannetto et al. (2012)" "Emiroglu et al. (2018)" "Dicenzo et al. (1995)" "Emiroglu et al. (2020)" ...
#> $ comment: chr "none" "only from Sakarya River Basin (Turkey)" "min.len not made clear (assumed same as Spotted Bass); same as Spotted Bass (Alabama subspecies)" "only from Turkey" ...
head(WSlit)
#> species units type ref measure method min.len
#> 1 Aegean Chub metric quadratic 75 TL EmP 70
#> 2 African Sharptooth Catfish metric quadratic 75 TL EmP 180
#> 3 Alabama Bass metric linear 75 TL RLP 100
#> 4 Ankara Nase metric quadratic 75 TL EmP 70
#> 5 Arctic Grayling metric linear 75 TL RLP 150
#> 6 Arctic Grayling metric linear 75 TL EmP 150
#> max.len int slope quad source
#> 1 220 -3.801 1.7830 0.3290 Giannetto et al. (2012)
#> 2 450 -3.668 1.8850 0.2087 Emiroglu et al. (2018)
#> 3 NA -5.598 3.2904 NA Dicenzo et al. (1995)
#> 4 240 -10.017 7.4020 -0.9710 Emiroglu et al. (2020)
#> 5 NA -5.241 3.0830 NA Gilham et al. (2021)
#> 6 NA -5.279 3.0960 NA Gilham et al. (2021)
#> comment
#> 1 none
#> 2 only from Sakarya River Basin (Turkey)
#> 3 min.len not made clear (assumed same as Spotted Bass); same as Spotted Bass (Alabama subspecies)
#> 4 only from Turkey
#> 5 authors note that either RLP or EmP method may be used
#> 6 authors note that either RLP or EmP method may be used