The problem of overfishing in the world's oceans could be rectified in two decades if we would all just knuckle down.

This was the word from BBC natural history unit producer Hugh Pearson, formerly the assistant producer for the acclaimed Blue Planet film series.

On June 31 and July 1, he will be in Bermuda to give lectures and show two of his films 'The Great Feast' and 'The Great Tide'. The films will be shown at the Bermuda Underwater Exploration Institute (BUEI) a joint project of the Bermuda Aquarium Museum & Zoo (BAMZ) and the BUEI.

The films are part of the BBC's 'Nature's Great Events' television wildlife documentary series.

The series looks at how seasonal changes powered by the sun cause shifting weather patterns and ocean currents, which in turn create the conditions for some of the planet's most spectacular wildlife events.

The series is narrated by David Attenborough.

Mr. Pearson has spent 15 years observing and filming the world's oceans.

"I am concerned about climate change, but it is one of many issues that the oceans face," he said. "A more pressing concern, and concern which is more easily addressed is overfishing.

"Overfishing is a terrible problem," he said. "The whole of the world's oceans are being overfished.

"It is affecting pretty much everywhere. And it is possible, relatively quickly, to fish sustainably again.

"It would take a decade or two depending on how much people bought into the principles of sustainability."

He said in the North Atlantic, 90 to 95 percent of the top predators such as marlins and sharks have been overfished.

"Predators are important for keeping a balance," he said. "Like any system you need the top predators to keep the system in balance.

"It keeps everyone healthy. If you don't have that, certain species can flourish to the determinant of others."

But there is no shortage of predators in his film 'The Great Tide' which looks at winter's sardine run along the South African coast.

'Frenetic' would be a good word to describe many scenes in the film.

In one, sharks, gannets, dolphins and whales all thrash and vie with each other for millions of tasty sardines.

The sardines are driven north along the eastern coast of South Africa in the winter, if the conditions are right.

Unfortunately, they aren't always right. Mr. Pearson tried to film the sardine run in 2007, and 2008, but the sardines didn't run that year. It is thought that this might be linked to climate change the waters may have been too warm for them to make the run.

"I do think climate change is something we also need to tackle," said Mr. Pearson.

When the sardines do decide to run, they provide a tasty snack for all manner of animals in the area.

Capturing the frenzy of animals chasing the sardine required cameras at several different angles.

"A helicopter filmed from above," said Mr. Pearson. "A boat filmed topside action, and cameramen were in the water filming, which was the most hazardous place of all."

Cameramen were keeping company with hundreds of over-excited sharks.

"Ultimately, they are all fish eating sharks," said Mr. Pearson. "But there is a risk that they could take a lunge at you.

"They wouldn't kill you, but they would hurt you."

For this reason, the cameraman always has a buddy in the water with him to keep watch.

"For most of that filming I was in the helicopter," said Mr. Pearson. "I was directing the aerials because they are the most complicated to film. Sometimes, I was topside on the boat."

Mr. Pearson said 'The Great Feast', about the summer plankton bloom off Alaska, is not quite so intense but it still has its moments.

"There were a couple of sequences that were quite interesting," said Mr. Pearson. "In one scene an Orca, or killer whale, attacked and killed a male sea lion."

A cameraman got into the water, attached to the boat, and filmed the attack on the sea lion.

"That took quite a lot of courage and knowledge to be able to do that safely," said Mr. Pearson.

In one scene, a humpback whale mother and her calf glide across the ocean, high above the cameraman's head.

"It is not true that humpback whales are gentle giants," said Mr. Pearson. "They are very big, powerful animals.

"The female we filmed with her calf was very gentle. She was very comfortable with us in the water. She was the friendliest whale we had seen there in 35 years.

"But there were other females and males who made it pretty clear they didn't want us close. They would nudge us away. They are 40-ton animals covered in barnacles. If they wanted to hurt you they could cut you in half in a flash.

"With any situation that has potential danger, you need to assess it and make sure danger is minimised."

He said the most dangerous film he has shot in his career involved the sardine run in 'The Great Tide'.

"If you watched the last twenty minutes of that, we had our camera crew in the water with a lot of sharks," he said. "That has hazards with it."

He said some of the shots may look easy, but they weren't.

"Often it takes weeks and months to get those shots," said Mr. Pearson. "And the whale can be gone with just one flick of her tail."

This will be Mr. Pearson's first trip to Bermuda. He said he was looking forward to the trip, and also to meeting people in Bermuda's marine research community.

"I am always scouting for potential films," he said. "I am always on the lookout for good stories that you can turn into a film and show people."

Mr. Pearson is originally from London, England and has a degree in marine biology.

"The sea has always been a passion of mine," he said. "After college I was working in medical sales. It wasn't for me.

"I have always loved watching nature films. I realised someone has to make them."

Naysayers told Mr. Pearson that it was a competitive business and he would never get in. He got in, as a runner.

"I started off at the bottom and worked my way up," he said. "I delivered messages and ran tapes around, and made tea."

A few weeks ago 'The Great Tide' received the Marine Animal Behaviour award at the Blue Ocean Film Festival in Savannah, Georgia. It was also a finalist for the Best of Festival award.

Mr. Pearson's advice to local upcoming film producers is that "persistence pays".

"And the great thing about what I do is it is accessible to everyone," he said. "Watch television and films and go to the cinema.

"Look at things analytically. What do you like that works? Do you notice different things about the camera? It is a job that you can learn from watching things."

'The Great Feast' will screen at the BUEI at 6.30 p.m. on June 30. 'The Great Tide' will show July 1 at the BUEI at 6.30 p.m.

Tickets for BUEI and Bermuda Zoological Society members is $15. Membership cards are required. Tickets for non-members are $20. Tickets for film with dinner and drinks is $33.75. Tickets are available from the BUEI or on 292-7219 or www.buei.org.