mack {gamair}R Documentation

Egg data from 1992 mackerel survey

Description

The data relate to the distribution of mackerel eggs and were collected as part of the 1992 mackerel survey aimed at assessing the mackerel spawning stock biomass using the daily egg production method.

Usage

data(mack)

Format

A data frame with 16 columns. Each row corresponds to one sample of eggs.

Details

At each of a number of stations located as defined in lon and lat, mackerel eggs were sampled by hauling a fine net up from deep below the sea surface to the sea surface. The egg count data are obtained from the resulting samples, and these have been converted to (stage I) eggs produced per metre squared per day - the egg density data. Other possibly useful predictor variable information has been recorded, along with identification information, and some information that is probably useless!

Source

The data are effectively a combination of datasets mackerel and smacker from the sm library. They were originally analyzed using GAMs by:

Borchers, D.L., S.T. Buckland, I.G. Priede and S. Ahmadi (1997) "Improving the precision of the daily egg production method using generalized additive models". Can. J. Fish. Aquat. Sci. 54:2727-2742.

Examples

data(mack)
# plot the egg densities against location
plot(mack$lon,mack$lat,cex=0.2+mack$egg.dens/150,col="red")

[Package gamair version 0.0-5 Index]