marindicators (version 1.0.0)

fishingInBalance: Calculates the Fishing-in-Balance Index

Description

This function calculates the Fishing-in-Balance (FiB) Index of fisheries landings for \(j\) areas and \(i\) years.

Usage

fishingInBalance(land, TL.table, minTL = 0, TE = 0.1, base.start,
  base.end, years)

Arguments

land

A dataframe of commercial landings data with columns YEAR, ID, SPECIES and CATCH. YEAR indicates the year the landing was recorded, ID is an area code indicating where the landing was recorded, SPECIES is a numeric code indicating the species landed, and CATCH is the corresponding landed weight.

TL.table

A dataframe with columns SPECIES and the corresponding TL_LAND (trophic level). Entries in the SPECIES column should be the unique values of species codes in land (or a subset thereof). Other columns in TL.table are ignored.

minTL

The minimum trophic level of species to include. Default is minTL = 0.

TE

Trophic efficiency. Default is TE = 0.1, i.e., a trophic efficiency of 10%.

base.start

Year indicating the beginning of the baseline period. The average landings and average mean trophic level of the landings over the baseline period are used as baseline values to calculate FiB (see Details). land must include data for the baseline period.

base.end

Year indicating the end of the baseline period. The average landings and average mean trophic level of the landings over the baseline period are used as baseline values to calculate FiB (see Details). land must include data for the baseline period.

years

A vector of years for which to calculate indicator.

Value

Returns a dataframe with three columns: ID, YEAR, and FishinginBalance.

If there are no observations in land for spatial scale \(j\) and year \(i\), indicator value is set to NA.

Details

Fishing-in-Balance (FiB) Index: $$FiB = log(Y_k*(1/TE)^{TL_k}) - log(Y_0 * (1/TE)^{TL_0})$$ where \(Y\) is the catch, \(TL\) is the mean trophic level in the catch, \(TE\) is the transfer efficiency, \(k\) is any year, and 0 refers to any year used as a baseline. By default, \(TE\) is set to 0.10 (Pauly and Christensen 1995).

This indicator captures changes in fishing strategies and their impact on system productivity: a positive FiB index indicates that the fishery has expanded and/or bottom-up effects are occurring, and there is more catch than expected, while a negative FiB index indicates it is likely that the fishing impact is so high that the ecosystem function is impaired and the ecosystem is less productive owing to excessive fishery removals (Pauly et al., 2000).

References

Bundy A, Gomez C, Cook AM. 2017. Guidance framework for the selection and evaluation of ecological indicators. Can. Tech. Rep. Fish. Aquat. Sci. 3232: xii + 212 p.

Pauly D, Christensen V, Walters C. 2000. Ecopath, Ecosim, and Ecospace as tools for evaluating ecosystem impact of fisheries. ICES J Mar Sci 57:697 706

See Also

Other resource potential indicators: allPotential, resourcePotential

Examples

# NOT RUN {
data(land)
data(species.info)
fishingInBalance(land, TL.table = species.info, minTL = 0, TE = 0.1,
   base.start = 2014, base.end = 2015, years = c(2014:2019))
# }