'Dead zones' prompt tour operator Pennicott to fund marine study of D'Entrecasteaux Channel

For more than two decades, Rob Pennicott has taken visitors on boat tours of the D'Entrecasteaux Channel, the waterway between Bruny Island and mainland Tasmania.

The regular snorkeller loves to explore the area both above and below its surface, but he is alarmed by changes he has noticed.

"What I've seen over the past 25 years are major changes, and I'm really interested in true sustainability for future generations," said Mr Pennicott, tourism operator and local.

He is so concerned that his philanthropic foundation has given $900,000 to scientists to take a look.

His observations have him worried — and he's not alone.

Mr Pennicott said he was seeing fewer abalone and lobster and areas that appeared to be devoid of life.

"In a dead zone, I'm seeing very dark colour, very little life, areas with no abalone, no crayfish, the things you get used to seeing all the time just aren't there, and there's sludge as well in those areas," Mr Pennicott said.

On this day, Mr Pennicott is a passenger on a research vessel, watching as scientists survey reefs in the channel with underwater cameras. 

This is the study his organisation is funding.

Mr Pennicott said changes to the channel were a regular topic of conversation among locals and colleagues.

Some people argue the shifts are natural, but others blame the salmon-farming industry in the channel. 

Rob Pennicott is unsure and wants evidence.

"There are a lot of salmon farms. I've had meetings with salmon farms. They think it's a good chance it's agriculture and global warming," he said.

Jeff Ross, a senior scientist with the Institute for Marine and Antarctic Studies (IMAS), has worked on Macquarie Harbour and the D'Entrecasteaux Channel.

He admitted that monitoring of the channel has not kept up with the expansion of salmon farms down the waterway.

"For some of those habitats, like rocky reefs, as the industry expanded, monitoring hasn't kept up. There's certainly info on rocky reefs, but we've never had the opportunity to provide this really holistic systematic approach," Professor Ross said.

"It's really hard to provide evidence to decision makers without baseline studies.

"We didn't understand enough about that system before the industry [salmon] expanded, and now we're … having to deal with those consequences," he said.

The money will fund a five-year study, which is already underway, with divers to survey reefs across the waterway.

Scientists are happy private money has stepped in where the state government has been reluctant to go.

"Long-term money is generally underfunded, and that's Australia-wide, not just in Tasmania, so a generous donation is allowing us to make a sustained long-term effort in the channel," team leader Camille White said.

The study will cover a much larger area than other monitoring programs.

It's early days, but already the team has filmed a mix of healthy reefs and dead zones.

As Mr Pennicott watches, their underwater cameras also inadvertently drag up bright green algae, a weed that locals and scientists alike are talking about.

"It's the one people complain about a lot, that's where you get the stories, 'We didn't see any of this 20 years ago,'" Dr White said.

For Rob Pennicott, it's an important start.

He is hopeful the research will help answer some questions, once and for all, and help protect a treasured waterway.