Watchdog group Guardians of Pauatahanui Inlet marked Sea Week 2001 by inviting Mike Hine of NIWA to present an illustrated talk on the findings of his research into the health of cockles in the Pauatahanui Inlet. It was a sobering evening as Mike, contrary to all expectations, had found that cockles in the Inlet were very unhealthy. Tissue exposed to the water showed significant inflammation, similar to pneumonia in humans. This was a disconcerting result for a study originally designed to establish the usefulness of cockles as an indicator species.
Mike had selected two pairs of similar harbours for the study - Kaipara and Manukau, and Porirua and Pauatahanui - a polluted and a pristine example at either end of the North Island. The cockles in Pauatahanui were the only ones to show this level of damage. In looking for reasons for this type of pathology, Mike pointed to the fact that roads almost completely ring the margins of the inlet. Overseas literature seems to suggest that polycyclic aromatic hydrocarbons (PAH's) in road run-off could be implicated. More research is urgently needed to identify the culprit irritants in the water. The Mayor of Porirua and deputy Chair of Wellington Regional Council, both present at the talk, have both been given this strong message to take back to their councils. If the link between cockle ill-health and roading is confirmed, resolving storm water and roading issues around the Inlet will need to be given high priority.
