estimateLake: Lake-Wide Fish Estimates from Acoustic and Midwater Trawl...

Description Usage Arguments Details Value

View source: R/estimateLake.R

Description

Estimate lake-wide fish density and total number (in number per ha and millions) and biomass density and total biomass (in g per ha and t) from acoustic and midwater trawl data.

Usage

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estimateLake(
  maindir,
  rdat = "ACMT",
  ageSp = NULL,
  region,
  regArea,
  TSrange = c(-60, -30),
  TSthresh = 1,
  psi = 0.007997566,
  soi = c(106, 109, 203, 204),
  spInfo,
  sliceDef,
  short = TRUE,
  descr = "ACMT Estimates"
)

Arguments

maindir

A character scalar giving the directory where rdat is located and where output will be placed. Use forward slashes, e.g., "C:/temp/".

rdat

A character scalar giving the name of the RData file in maindir with the acoustic and midwater trawl data, typically the output from readAll.

ageSp

A numeric vector giving the species codes for species for which age-length keys should be used, default NULL.

region

A character vector, names of regions used in laying out sampling design.

regArea

A numeric vector, corresponding areas (in ha) of region.

TSrange

A numeric vector of length 2, the target strength range of interest, minimum and maximum in dB, default c(-60, -30).

TSthresh

A numeric scalar, the minimum number of binned targets required to incorporate the TS information from a given (interval by layer) cell.

psi

A numeric scalar, the transducer-specific two-way equivalent beam angle in steradians, default 0.007997566.

soi

A numeric vector, codes of fish species for which estimates will be generated, default c(106, 109, 203, 204).

spInfo

A data frame with five variables

  • sp = numeric, species code, must include all codes listed in soi, may include codes not listed in soi

  • spname = character, species name

  • lcut = numeric, the length cut off (in mm) at which to divide the corresponding species data into two groups (those with fish lengths <= lcut and > lcut) for estimation, use 0 for species with no length cut offs

  • lwa and lwb = numeric parameters of length-weight relations, Wg = lwa * Lmm ^ lwb, where Wg is the weight (in g) and Lmm is the total length (in mm)

sliceDef

A list of at least two named sub-lists defining the slices into which observations will be classified. Each sub-list contains one or more named numeric vectors of length two, identifying the parameter (the name of the vector) and the range of values (see Details) that contribute to the slice definition, with one exception. For slicing by regions, the named vector is character (not numeric), is of length one or more (not necessarily two), and specifies all of the regions that contribute to the slice definition. The name of each sub-list is the name of the slice to be assigned. See Examples.

short

Logical scalar, indicating aspect of map area. If TRUE, the default, the mapped area is assumed to be wider (longitudinally) than tall. Used to better arrange multiple maps on a single page.

descr

A character scalar to be incorporated in the name of the saved output files, default "ACMT Estimates".

Details

The sigma for each acoustic cell is estimated as the mean of the linearized target strength (TS) weighted by the number of targets in each dB bin using the TS frequency distribution.

The number of scatterers per unit volume, Nv, is estimated according to Sawada et al. (1993) (see estNv). So called "biased" sigmas where Nv > 0.1 are replaced with mean "unbiased" sigmas from cells in the same layer and (if possible) transect. Then, Nv is recalculated.

Value

A rich text file (rtf) with a *.doc file extension (so that it will be opened with Word by default) is saved to maindir.

Seven different data frames are saved as objects in an Rdata file and are written to csv files in maindir:

The Rdata and csv files are named using the lake and the year.


JVAdams/EchoNet2Fish documentation built on Feb. 15, 2021, 4:27 a.m.