A karakia was performed by local iwi, and the whale was buried.
Determining a cause of death would be difficult, Mr Tawa said.
"We can't confirm the cause of death, but it was tangled in some of the spat lines, which are young muscles," he said.
"It could have been dead before it arrived or got caught up in the lines, we're just unable to confirm a cause of death."
However, if it had been caught up in the lines, DoC would have expected reports of a whale in distress, Mr Tawa said, as it was close to a popular fishing spot and boating route.
A whale getting fatally tangled in spat lines was "quite unusual", he said, as the we're "reasonably light and easy to get out of".
"I guess it's not normal, I'm only aware of two other incidents where it's occurred in the last kind of 20 years," Mr Tawa said.