"I can, I can swim up, upstream!"

North Shore City Council is hoping a new 10m-long 'fish bridge' built in Eskdale Stream, Birkdale, last week will encourage fish life to move further upstream and breed.

Close to seven cubic metres of rocks have been carefully placed in the stream to help fish (including white bait/inanga) swim up to and through a culvert.

Project manager Tom Mansell says a study of 26 streams carried out in 2002 highlighted the barrier for fish passage in the stream.

"The Stream Walk Programme looked at fish passage, upstream movement and habitat," he said. "The presence of fish life in our urban streams is a good indicator of general environmental health and it was important to identify any areas where man-made works may have affected that environment.

"This new fish bridge is part of a series of works designed to improve the condition of the stream and address stormwater issues in the catchment. The placement of rocks in the stream will also protect the surrounding banks from erosion."

A population count carried out near the Eskdale culvert before the establishment of the fish bridge found more than 70 fish in the stream including longfin and shortfin eel, redfin and common bully, inanga and koura.

Mr Mansell expects the rock placement to encourage more fish travelling up the stream past the culvert.

"We'll measure the resident fish population below and above the culvert area during the next two breeding seasons", he says. "Our findings will hopefully contribute to our knowledge of urban streams and give us some good pointers on how to minimise disturbance in the future."

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