Mrs Beresford said foul play was not the answer, and gave the wrong impression of her son.
"He used to say to me 'I'm a good person mum'."
Giving evidence, Senior Constable Paul Herman said 48-year-old Michael was described as a "very competent" fisherman, and had sent three text messages to family and friends on the day of his disappearance.
In one of the messages, he told a friend he was going fishing and would hopefully give him some of the catch later that night.
In her decision, Coroner Herdson said June 30, 2006 was the presumed date of Mr Beresford's death, but the cause of death remained unknown due to gaps in evidence.
"I can't improve the evidence and I can't speculate as to what might have happened."
She expected to make her full written decision available in a matter of weeks.
Other inquests heard by Coroner Herdson and Coroner Deborah Marshall today included:
Andrew John Dawson - Warkworth, Auckland.
Mr Dawson went hunting in the Waiwhiu Valley and was reported missing by his family on April 1, 1987 just over two months before his 22nd birthday.
He had only been hunting once before and had little firearms experience.
Detective Nick Salter told the court he believed Mr Dawson had either met with an accident or been accidently shot by another hunter, with his body lost in the hilly terrain.
Coroner Marshall said she could indicate she would find he had died, but would release her written finding next week.
Peter Robert Austyn - Titirangi, Auckland
The 64-year-old was last seen by his landlady riding his bicycle on February 25, 1993.
He was described by police as eccentric, a keen cyclist and "ardent natural health follower", well known to Titirangi Library staff, which he frequented often.
His bike was found more than a year after his disappearance secured to a punga tree in an area of bush near South Titirangi Road.
Senior Constable Herman said police were concerned he went looking for fungi and might have misidentified a poisonous mushroom specimen for an edible one.
Coroner Marshall said she was reserving her decision but said she could indicate she was finding Mr Austyn dead.
Ang Ja Lee - Avondale, Auckland
The 35-year-old father went fishing at Piha Beach on January 20, 1991 and never came home.
Senior Constable Herman said the most likely scenario was Mr Lee had gone fishing and drowned.
Coroner Herdson reserved her decision but excluded suicide on the basis of the evidence.
Heather Joy Carroll, Te Atatu South, Auckland
The 39 year old was reported missing on July 5, 1981. Coroner Herdson said it was likely her death was self-inflicted.
