REstd: Relative Effort Based Standardization (REstd)

In FESta: Fishing Effort Standardization

Relative Effort Based Standardization (REstd)

Description

Standardizes fishing effort by adjusting for differences in fishing power among vessel types relative to a selected standard vessel. The method estimates the relative fishing power of each vessel type from observed CPUE values and converts raw fishing effort into a common-efficiency effort scale.

Relative fishing power is calculated as:

PA(i)=\frac{CPUE(i)} {CPUE(standard)}

where CPUE(i) is the catch-per-unit-effort of vessel type i and CPUE(standard) is the CPUE of the selected standard vessel.

Standardized effort is then computed as:

E_{std} = \sum_i \left[ PA(i)\times N(i)\times d(i) \right]

where N(i) is the number of boats and d(i) is the average number of fishing days for vessel type i.

Usage

REstd(
  data,
  year_col,
  vessel_col,
  boats_col,
  days_col,
  cpue_col,
  standard_vessel
)

Arguments

data	A data frame containing the columns of year, vessel information, number of boats, days of fishing and CPUE. See the example dataset REstd_dataset.
year_col	Specify the year column name (eg. "Year").
vessel_col	Specify the vessel types column name (eg. "Vessel_Type").
boats_col	Specify the number of boats column name (eg. "Number_of_Boats").
days_col	Specify the number of fishing days column name (eg. "Avg_Fishing_Days").
cpue_col	Specify the CPUE column name (eg. "CPUE").
standard_vessel	Specifying the reference vessel based on which relative fishing power will be calculated. If NULL, the function automatically selects a standard vessel from the available data.

Value

A data frame containing year-wise standardized effort (used as standardized CPUE index) along with a printed summary table and a dual-axis trend plot showing standardized CPUE and mean relative fishing power by year.

Note

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

References

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.

Robson, D.S. (1966). Estimation of the relative fishing power of individual ships. ICNAF Research Bulletin, 3, 5-14.

Sparre, P., and Venema, S.C. (1992). Introduction to Tropical Fish Stock Assessment. FAO Fisheries Technical Paper No. 306/1, 376 pp.

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("REstd_dataset")
result<-REstd(data = REstd_dataset, year_col = "Year", vessel_col = "Vessel",
      boats_col = "Boats", days_col = "Days",
      cpue_col = "CPUE", standard_vessel = 'A')
      print(result)

## End(Not run)

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