# S4 method for echosounder
summary(object, ...)an object of class "echosounder", usually, a result of
a call to read.echosounder(), read.oce(), or
as.echosounder().
further arguments passed to or from other methods.
Other things related to echosounder data: 
[[,echosounder-method,
[[<-,echosounder-method,
as.echosounder(),
echosounder-class,
echosounder,
findBottom(),
plot,echosounder-method,
read.echosounder(),
subset,echosounder-method