Protecting lampray fishes in Christchurch

28/04/2021

The Marshlands Bridge project is one of Christchurch’s most ecologically sensitive projects, with lizards (skinks), a NZ native climbing nettle and the lamprey fish all within the project area.

Before works could start the skinks had to be trapped and relocated outside of the project by the projects Herpetologist (lizard wrangler), and any climbing nettles within the site were relocated.

The riverbank and nearby drain are known breeding habitats of the lamprey. The lamprey (kanakana/piharau) is a unique freshwater fish species that has been around for 450 million years. It is a jawless fish, with a distinctive sucking disk mouth. The lamprey migrates into rivers to spawn, and the juvenile lamprey spends four years in rivers and streams before migrating out to sea. The lamprey is a taonga, and is a traditionally important mahinga kai species. It is threatened with extinction.

The team has ensured that the ecologist is on site before any excavation of the bank has occurred and that only areas cleared by the ecologist are earth worked. So far, over 200 juvenile lamprey have been relocated. The ecologist has been using electro fishing as well as sifting through the silt deposited in a half skip to make sure we save as many as possible. With over 50% of the bank checked so far, a final tally is likely to be in the 300’s. It is great to see our teams involved to help ensure this species will be around for another 450 million years.