sgr: Specific Growth Rate (SGR)

In aquacultuR: A Comprehensive R Tool for Zootechnical Metrics

Specific Growth Rate (SGR)

Description

This function calculates the Specific Growth Rate (SGR) based on the Instantaneous Growth Rate (IGR). The IGR is a useful metric, although hard to interpret. The SGR, derived from IGR, can then be easily interpreted as the percentage of Body Weight gained each day. The SGR is a growth metric for aquaculture products (e.g., fish, crustaceans, bivalves, algae), describing the increase in body weight over a period of time. Body weight can be substituted by other metrics, such as length. However, body weight is the used in the vast majority of studies and alternatives are not advised for the sake of consistency.

Usage

sgr(ibw, fbw, duration, return_igr = FALSE)

Arguments

ibw	numeric; value that is providing the initial body weight in grams.
fbw	numeric; value that is providing the final body weight in grams.
duration	numeric value that is providing the duration of the experiment in days.
return_igr	logical; default is FALSE. Indicates whether the instantaneous growth rate shall be returned together with the SGR or not.

Value

Returns a numeric, which is the SGR as percentage of the body weight gain per day, or a list containing the SGR and the IGR.

Author(s)

Anıl Axel Tellbüscher

Davide A. Machado e Silva

References

Crane, D.P., Ogle, D.H. and Shoup, D.E. (2020), Use and misuse of a common growth metric: guidance for appropriately calculating and reporting specific growth rate. Rev Aquacult, 12: 1542-1547. https://doi.org/10.1111/raq.12396

Examples

dplyr::mutate(weight2, SGR = sgr(ibw_g, fbw_g, duration = 84))

aquacultuR documentation built on Jan. 26, 2026, 5:07 p.m.