Horizons removes rabbit weir to enhance Ākitio River native fish passage

One of the greatest barriers to native fish migration in the Horizons Region, which has been in place for more than a century, has been removed in preparation for future inhabitants.

Horizons Regional Council freshwater coordinator – fish passage Courtney Bond says a large section of the Ākitio rabbit weir, located along the Ākitio River near Waione, was removed in early April to open up more habitat for native fish.
 
“The weir was built in 1889 as part of the Southern Hawke’s Bay Rabbit Fence in an attempt to halt the northward migration of rabbits. The fence slowed, but ultimately failed to stop, the migration.
 
“The weir, while built with the best intentions, had the impact of creating an impassable barrier for fish trying to get to upstream habitats.”
 
Native fish had been impeded from accessing more than 440 kilometres of river and tributary habitat since the weir’s construction, says Mrs Bond.
 
“Removing this barrier opens the upper reaches of the Ākitio River for fish passage, giving native fish such as tuna (longfin eel), common bully and redfin bully, as well as introduced trout, more habitat for breeding, feeding and living. 
 
“We worked with many partners throughout the removal process, including the Puketoi to the Pacific Catchment Collective, Rangitāne o Tamaki nui-ā-Rua, Ngāti Kahungunu ki Tāmaki-nui-a-Rua, Pouhere Taonga Heritage New Zealand, and the asset owner Toitū te Whenua Land and Information New Zealand. We are thankful for their expertise, input and support.”
 
The history of the weir will be acknowledged, with parts of the weir provided to the Dannevirke Museum, Pongaroa Community Hall and Weber Community Committee as part of a recognition project, says Mrs Bond.
 
“A 3D laser scan and photogrammetry survey of the weir was completed to digitally record the structure, while Horizons will host information about the weir on our website in the future and have a piece of the weir at our Woodville office.
 
“Many of Aotearoa New Zealand’s native fish need to move throughout freshwater waterways and the sea as part of their lifecycles, including whitebait species īnanga, kōaro and kōkopu. 
 
“There is one remaining barrier in the lower reaches of the Ākitio River preventing these species lower down the catchment from accessing the upper reaches. 
 
“Remediation options for this structure are being worked through with the community. One day in the near future, and after being excluded for more than 136 years, these whitebait species will be able to inhabit the upper reaches of the Ākitio River.”

Image: The weir before it was removed. The large concrete structure was impassable by native fish species.