MGMSstd: Multi-Gear Mean Standardization (MGMSstd)

In FESta: Fishing Effort Standardization

Multi-Gear Mean Standardization (MGMSstd)

Description

The Multigear Mean Standardization (MGMS) method was proposed by Gibson-Reinemer et al. (2017) to combine CPUE data collected using different sampling gears into a common relative scale suitable for community analyses. Initially, CPUE values are expressed as relative abundance:

RA_{ij}= \frac{c_{ij}/e} {TC_j/e}

where

• c_{ij} is the catch of species i in year (or sample) j.

• e is the sampling effort.

• TC_j is the total catch of all species in year (or sample) j.

To preserve both within-sample and among-sample abundance patterns, the total CPUE of each sample is standardized by the mean total CPUE across all samples:

MSC_{ij} = \frac{c_{ij}/e}{TC_j/e} \times \frac{TC_j/e}{\overline{TC}/e}

which simplifies to

MSC_{ij} = \frac{c_{ij}/e} {\overline{TC}/e}

where

\overline{TC}/e

is the mean total catch per unit effort.

Usage

MGMSstd(data, year_col, gear_col, species_col, cpue_col)

Arguments

data	A data frame containing year, gear, species, and CPUE columns.
year_col	Specify the year column name (eg. "Year").
gear_col	Specify the gear types column name (eg. "Gears").
species_col	Specify the species column name (eg. "Species").
cpue_col	Specify the CPUE column name (eg. "CPUE_value").

Value

The function produces:

• Gear-specific standardized CPUE tables.

• A multiline plot of total standardized CPUE by gear.

Note

CPUE should not contain zero values, if still zero values are present then all are replaced with minimum CPUE value.

References

Gibson-Reinemer, D. K., Ickes, B. S., & Chick, J. H. (2017). Development and assessment of a new method for combining catch per unit effort data from different fish sampling gears: multigear mean standardization (MGMS). Canadian Journal of Fisheries and Aquatic Sciences, 74(1), 8–14. https://doi.org/10.1139/cjfas-2016-0003

Varghese, E., Jayasankar, J., Sathianandan, T.V., Kuriakose, S., Mini, K.G., Gills, R., Muktha, M., Sreepriya, V. and Gopalakrishnan, A. (2023). A note on different methods for standardization of fishing efforts. Marine Fisheries Information Service, Technical and Extension Series, (257), 7-17.

Acknowledgements: The authors sincerely thank the Director, ICAR–Central Marine Fisheries Research Institute (ICAR-CMFRI), Kochi, for providing the necessary facilities and institutional support. The authors also gratefully acknowledge the support provided by the Indian Council of Agricultural Research (ICAR), Department of Agricultural Research and Education (DARE), Government of India, through the ICAR-National Fellow Project.

Examples

## Not run: 
library(FESta)
data("MGMSstd_dataset")

result <- MGMSstd(
  data = MGMSstd_dataset,
  year_col = "Year",
  gear_col = "Gear",
  species_col = "Species",
  cpue_col = "CPUE"
)
print(result)

## End(Not run)

FESta documentation built on Aug. 20, 2026, 5:10 p.m.