When rangers and police swooped, the culprits had gone, but their nets were seized.
"We have a couple of leads and they are being followed up," Mr Carlton said.
Since then, rangers had found two other unattended nets that were also seized.
The law says whitebaiters must always be within 10m of their set nets and fishing is permitted only from 5am to 8pm, or 6am-9pm once daylight saving begins in October.
But apart from the two seizures of nets there had been no problems, Mr Carlton said.
As for the catches across the Bay's rivers, they had been "variable".
"We've had some people telling us they have had reasonably good catches and others telling us there's not a lot out there."
Mr Carlton said the start of the season had been affected by poor water conditions after heavy falls of rain in the high country.
"It all comes down to the water conditions."
Patrols will be continued regularly through to the end of November, when the whitebaiting season wraps up.