Ducks Unlimited is doing restoration work in the Quatse Estuary.
Spokesperson Sarah Nathan says an old log weir had been put in to hold back water in one area of the estuary.
She says a data logger installed in the area found the water was getting too warm for the fish. Engineers are removing the larger log weir and will replace with a lower rock weir. Nathan says that should let in more tidal water that should help flush out the warmer water in the area.
Nathan says the crews are also creating benching to support food plants for ducks and salmonid species.
She says the new vegetation will be planted later this spring.