A passion for exploring and understanding the natural world drove Great Yarmouth naturalist, Percy Trett, who has died aged 86 after a long illness.

For more than 25 years, he was one of the team of four specialists who wrote the EDP's In the Countryside column. After the death of Ted Ellis, who always signed himself as EAE, he became a regular contributor in 1986. 'Ted Ellis was really my mentor . . . who was like an older brother to me,' he told the EDP on his 80th birthday.

He was still working in the family's Victoria Road garage in Yarmouth at the age of 84, although it was later sold in early 2011. It marked the end of an era of Trett's business involvement in the town, which had been started by his grandfather, also called Percy, in 1898.

A magistrate for 26 years, he had also been chairman of Great Yarmouth Juvenile Court, and was also actively involved in a range of bodies and charities in the town. He was a former chairman of Yarmouth branch of the RSPCA, the Norfolk and Suffolk Animal Trust and the Yarmouth Archaeological Society. He was especially pleased to have been elected as president of the Norfolk & Norwich Naturalists' Society.

Born in Ormesby on May 11, 1926, he started learning about the natural world when he was taken out by his grandfather in a sailing boat on the Norfolk broads. After leaving Yarmouth's former Duncan Hall School, he wanted to study marine biology at Leeds University. However, the war intervened and he ended up flying Tiger Moths, Lysanders and gliders in the Army Air Corps as well as completing a series of parachute jumps.

Returning to Yarmouth in 1945, his father, who was then in poor health, asked if he would take over the garage business for a year. 'It turned into a long year,' he recalled. For many years, he also turned part of the garage after hours over to local weightlifters and fitness enthusiasts. As a seasoned weight-trainer, his club had almost 50 members at one stage.

His enthusiasm for all aspects of wildlife, and for sharing it with others, led to his founding the Norwich branch of the Wild Fowlers' Association and also the East Anglian branch of the British Sub-Aqua Club.

Shortly after the war, he took up diving in the North Sea – wearing a coloured woollen wet suit and then made a primitive breathing apparatus with oxygen cylinders cobbled together from army surplus. While equally happy to be sitting on the seabed feeding crabs and lobsters, he also explored the coast. Finds included the wreck of the steamer tug, Victoria, which sank in 1888 after striking the church steeple of the former village of Shipden, off Cromer. A part of the vessel was later presented to Cromer Museum.

In an early column in September 1986, the 60-year-old described diving to 65ft down into the hold of a wrecked coaster – and then catching a lobster, weighing more than 8lbs and with claws larger than a man's hand. 'In 40 years of diving, I have never seen such a concentration of lobsters,' he wrote.

Over many years, he also treated and cared for a succession of weary seabirds at his former Victoria Road home including ospreys.

After he had been diagnosed with Parkinson's disease, he maintained his strict daily discipline of rising at 5.30am – and was normally the first to arrive in his overalls at garage before 8.30am. Well into his 80s, he once said: 'People tell me that I am the oldest MOT tester in the country.'

He was also one of the hardy band of swimmers, who worked up an appetite for Christmas dinner by going for a dip. He had braved the winter waters off Yarmouth for more than 42 years, telling the EDP when aged 61: 'We are old fools.'

He also built up an amazing photo archive of the natural world, including some 12,000 old pictures of the town.

Married for almost 60 years, he is survived by his wife, Jan, and leaves three children, Marcus, Rebecca, and Simon, and two grandchildren.

Funeral arrangements to be announced.Michael Pollitt