meh {gamair}

Data from 2010 horse mackerel and mackerel egg survey

Description

The data relate to the distribution of horse mackerel (meh, Trachurus trachurus) eggs and mackerel (med, Scomber scombrus) eggs and were collected as part of the 2010 mackerel survey aimed at assessing the mackerel spawning stock biomass using the daily egg production method.

Usage

data(med)
data(meh)

Format

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

count

The number of stage I eggs in this sample.

la

sample station latitude

lo

sample station longitude

vol

volume of water sampled

T.surf

surface temperature in centigrade

T.x

temperature at x metres depth.

T1.x

Second temperature measurements.

Sal20

Salinity at 20m depth

b.depth

seabed depth in metres for med only.

lon

The longitude of the sample station in degrees east.

lat

The latitude of the sample station in degrees north.

time

The time of day (in hours) at which the sample was taken.

salinity

The salinity (saltiness) of the water at the sampling location.

period

sampling period

country

Country responsible for sample

ship

Vessel ID

DT

sample data and time

ID

Sample ID

gear

type of sampling gear used

The remaining fields are undocumented.

Details

The original data files do not always exactly match the file documentation, so these data should not be treated as definitive.

Source

ICES Eggs and Larvae Dataset 2012, ICES, Copenhagen

http://www.ices.dk/

http://eggsandlarvae.ices.dk/Download.aspx

Examples

require(gamair)
par(mfrow=c(1,2))
data(meh);data(med);data(coast)
# plot the egg counts against location
plot(meh$lo,meh$la,cex=0.2+meh$count^.5/10,col="grey",
     pch=19,xlab="lo",ylab="la",main="horse mackerel")
ind <- meh$count==0
points(meh$lo[ind],meh$la[ind],cex=0.1,pch=19)
lines(coast)

# same for med
plot(med$lo,med$la,cex=0.2+med$count^.5/10,col="grey",
     pch=19,xlab="lo",ylab="la",main="mackerel")
ind <- med$count==0
points(med$lo[ind],med$la[ind],cex=0.1,pch=19)
lines(coast)