Two honorary fishery officers arrived to check compliance.
They were met with a degree of opposition and intimidation by some of those present.
While the officers were inspecting the seafood for compliance, Engu approached one while armed with a bait knife and objected to their presence.
The victim was 75 years old.
When the officer said some of the catch might be seized, Engu said to him: "I'll murder you," while still holding the knife and jabbing it in the officer's direction.
The officers completed their inspection and left, satisfied the group's catch was compliant.
Police were notified of Engu's behaviour.
The following day, Engu was stopped by police on Riverside Dr and spoken to about his behaviour the previous day.
The victim was present and, on seeing him, Engu said: "You are done. I will get someone to take you out."
The bait knife was then seized by police.