Estimating the Relative Abundance of Fish From a Trawl Survey
This function applies the time series method of Pennington (1986) for estimating relative abundance to a survey series of catch per tow data
vector containing the time series of numeric year labels.
vector containing the time series of mean catch per tow data.
a logical value indicating whether the natural log-transform should be applied to the mean catch per tow values. Default is TRUE.
a logical value indicating whether a graph of the observed and model fit should be drawn. Default is TRUE.
Parameters for a first difference, moving average model of order 1 are estimated from the trawl time series using function
Following Equation 4 in Pennington (1986), fitted values are calculated from the model residuals and the estimate of theta.
List containing summary statistics (sample size (n), the first three sample autocorrelations (r1-r3) for the first differenced logged series) and parameter estimates (theta, theta standard error, and sigma2), the observed log-transformed index and fitted values, and the ARIMA function output.
Gary A. Nelson, Massachusetts Division of Marine Fisheries email@example.com
Pennington, M. P. 1986. Some statistical techniques for estimating abundance indices from trawl surveys. Fishery Bulletin 84(3): 519-525.
Want to suggest features or report bugs for rdrr.io? Use the GitHub issue tracker.