"So far the (autopsy) results are not inconsistent with drowning," said Kinney.
Kinney said there was no evidence of trauma or foul play.
The coroner's office is still in the process of performing a toxicology screen to see if Stevenson had any alcohol or drugs in his system.
"(A drowning diagnosis) is a process of exclusion," said Kinney.
"We have to eliminate all other possibilities."
The final autopsy results will not be released for another three months.
Stevenson, 42, disappeared last Thursday night from a fishing boat anchored near Wool Bay, about 10 kilometres west of Yellowknife on Great Slave Lake.
Commercial divers found his body Aug. 19, not far from the area where he disappeared.
Fishermen at Wool Bay say Stevenson's boat, the A7, was sailing out of Yellowknife before he disappeared, not Hay River as had been previously reported. Stevenson was the father of a four-year-old daughter.
He was born in Hay River, where his father still resides, says family spokesperson Karen Thomas, his first cousin. Stevenson's mother died when he was very young.
"He was very kind-hearted," says Thomas, noting he often tried to help others. "He never had a mean word to say about anyone."
She says her cousin worked very hard to support his family.
"Jimmy started fishing when he was very young," she says, adding he also worked as a camp attendant at Diavik for about five years.
"He's going to be missed by his family quite a bit," she says. "It was an awful accident."
Thomas says the family is relieved that their loved one's body was recovered from Great Slave Lake, since it will allow closure on the tragedy.
A funeral for Stevenson is to be held today in Hay River.