Coming back into the job market two years later, Mr Bowman set to looking at what was next.
''The first job was an animal pest manager for the Southland Regional Council [now Environment Southland].''
Environmental management was a big change from what he was used to and the job required a lot of learning in the initial stages, he said.
At that stage, the regional council had been operating for only about three years and had just taken over the old pest board function.
''Council really didn't know how they were going to deal with it.''
At the time, rabbits were the major pest in Southland, and in 1997 the region's first regional pest management strategy was developed.
The calicivirus disease was released the same year, which had quite an impact in Southland, Mr Bowman said.
''When I started there were still some quite major infestations in parts of Southland but with land-use change, particularly dairying, and calicivirus it's almost like their numbers followed council policy,'' he said, smiling.
While rabbits were still a problem for some, other pests had made the way in to the region, some staying and others going.
After rabbits, it was bovine Tuberculosis (Tb).
In 1994, when Mr Bowman first started, there were 55 infected herds in Southland.
''In 2008 it was down to zero herds on movement control. At the peak of the programme the council team had 1 million hectares in possum control.''
The control team had possum numbers incredibly low, even below the targeted levels, Mr Bowman said.
''I think they got to about 2% trap catch or below.''
In 2007, the initial pest management strategy was reviewed after 20 years.
While rabbits and possums, as well as plants such as gorse and broom, were still a pest, the council shifted its focus to biodiversity and protecting areas of valued land.
One of Mr Bowman's most enjoyable experiences working for the regional council has been building relationships with other organisations.
The Department of Conservation, Land Information New Zealand, the Ministry for Primary Industries; the list goes on.
With wilding pines one of the biggest issues in recent times, work with the Mid Dome Wilding Trees Charitable Trust had been incredibly rewarding, Mr Bowman said.
When he finishes with Environment Southland next month, he will continue to work with the trust, serving as a trustee.
Another major battle he has been a part of is containing undaria, better known as Asian kelp, in Fiordland.
''We're trying to prevent further spread but it has been a difficult battle,'' he said.
Underwater pest management was a whole different kettle of fish for the council.
''You're never going to get on top of everything. We've tackled some difficult problems. Through partnerships and working with other organisations and stakeholders we can make a difference.''
One positive battle had been with velvetleaf, which was found in the region in 2016, but there had been no more cases since then.
Over three months, 4000ha was covered on foot looking for the pest plant, he said.
''One of the things that has kept me in the job has been the variety ... We've gone way beyond rabbits and broom.''
At the same time, although retirement appears to be just around the corner, Mr Bowman cannot take off his biosecurity hat just yet and warns farmers to be vigilant over velvetleaf, as seeds could lie dormant.
For now, it is business as usual, before he heads for some fishing and to spend time with family.
''I will miss the people here. I've enjoyed it; I wouldn't have been here for so long if I didn't,'' he said.
