Description Usage Arguments Details Value Author(s) References Examples

View source: R/meanLengthCommunity.R

This function calculates the Mean Length of the Community
weighted by biomass or abundance for *j* areas and *i* years.

1 | ```
meanLengthCommunity(X_length, metric, years)
``` |

`X_length` |
A dataframe of fishery independent data derived from research
vessel survey data or model output, with columns |

`metric` |
A character string indicating which column in |

`years` |
A vector of years for which to calculate indicator. |

*MeanLength = Σ(Length_m * metric_i)/Σ metric_j*

where
*Length_m* is the length (cm) of an individual in size class *m*,
*metric_i* is the biomass or abundance of species *i* and
*metric_j* is the total biomass or abundance of the community (Shin et
al., 2010).

Returns a dataframe with 3 columns. `ID`

, `YEAR`

, and
`MeanLength_metric`

.

If there is no data for spatial scale *j* in year *i*, indicator
value is assigned `NA`

.

Danielle Dempsey Danielle.Dempsey@dfo-mpo.gc.ca, Adam Cook, Catalina Gomez, Alida Bundy

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.

Shin, YJ, Shannon LJ, Bundy A, Coll M, Aydin K, Bez N, Blanchard JL, Borges, MF, Diallo I, Diaz E, Heymans JJ, Hill L, Johannesen E, Jouffre D, Kifani S, Labrosse P, Link JS, Mackinson S, Masski H, Möllmann C, Neira S, Ojaveer H, Abdallahi KM, Perry I, Thiao D, Yemane D, and Cury PM. 2010. Using indicators for evaluating, comparing and communicating the ecological status of exploited marine ecosystems. Part 2: Setting the scene. ICES Journal of Marine Science, 67: 692-716

1 2 3 4 5 | ```
data(X_length)
# Weighted by abundance
meanLengthCommunity(X_length, metric = "ABUNDANCE", years = c(2014:2019))
# Weighted by biomass
meanLengthCommunity(X_length, metric = "BIOMASS", years = c(2014:2019))
``` |

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