On 6th June Allegrow held a field day at Otanemutu Lands Trust farm and orchard near Ōpōtiki. The farm is managed by Aaron Johnston who is passionate about the history of the land and biodiversity.
The farm is adjacent to the coast and the many waterways and drains run from the hills towards the coast providing a passage for fish species between these areas. The property includes protected wetland areas and retired bushland. A new wetland area is proposed near the roadside where it can be enjoyed by trustees and kaumatua without disturbing farming activities.
The kiwifruit orchard is irrigated using water from a purpose built pond. The area surrounding the pond is fenced off and includes native plants. There are two large culverts which convey the overflow from the pond into the stream below. The culverts were installed before much thought was given to the passage of fish. Modifications to the culverts to improve fish passage have been carried out by fish passage expert Kelly Hughes (ATS Environmental).
Jo Cranswick, Fish Passage Officer from BOPRC attended the field day and provided advice to participants. Baffles have been installed in the culverts to break up the flow, reduce velocity and create places for the fish to rest on their way up the culvert.
The weir at the culvert outlet directs the water across the mussel spat rope. The mussel spat ropes provides a medium for climbing fish species to travel upstream.
The effectiveness of fish passage structures can be monitored using EDNA testing before and after installation. A sample of water is taken and sent away and analysed for the different types of DNA to see what species are present.
You can find more information on fish passage here or by contacting your Regional Council.
Lilian Harley – Director