A gear of the right name proves nothing: it might be one the model already
had, and setting its effort would then leave the fishing the scan is supposed
to replace still switched on, so the scanned mortality would be added to the
existing mortality rather than replacing it. Nor is it enough for the gear to
look like the one scanFishingMortality() adds, for the same reason.
scan_gear_installed(params, gear_name, species, gear = NULL)TRUE if this model already carries the installation.
A MizerParams object.
The name of the gear to check.
The target species.
The gear whose mortality the scan replaces, or NULL for all of the gears catching the species.
What is checked is therefore the whole installation, exactly as
install_tmp_gear() leaves it: the name carried by exactly one row, which
catches the target species with catchability 1, and at least one original
gear still present with every gear it was supposed to replace switched off.