We have several invasive species trying to be dealt with here in NZ at the mo. One is a saltwater based plant called "sea squirt". It seems to be none agressive, as in, it stays within close proximity to where it was released. So control is by quaranteeing the area and then they try finding plants and eradicate them. But the one that is out of controll is a fresh water
species of algae called "Didemo". It is rampantly spreading across NZ totaly out of control and is so virilant, it almost destroys any water
way it enters. NZ simply doesn't get cold enough to control this species as it does in its natural environment
IMO, I don't think our "border" is being controlled enough anymore. We seem to be playing catchup to a whole lot of criters and plants that are arriving here.
Here in Blenheim, a species of Australain Blackwidow spider was found last week. And an Asian Golden Orb spider was found just a mile away from were I live. We now have a very well established South African White tail spider. The German Wasp and Argintinian Ant are both out of control. Auckland
has frequent spraying for the painted apple moth and some other criter I can't remember and the wet lands around Marlborough are yearly sprayed for some invasive grass and the White Nile mosquito. When I was a boy, the only poisonouse creature we had was a little spider that lived in dead logs
on the beach called the katipo and even then it wasn't dangerousely poisonouse.
Of course there are too numerouse to mention numbers of other introduced species that were brought here with the first settlers. Oh boy did they stuff up.