Shellfish sites have poor water quality

16:00, Mar 31 2014

Shellfish gathering from some Southland sites could be a risky business.

For the third year in a row, water at shellfish gathering sites across the region monitored by Environment Southland was poor.

For the season July 2012 to June 2013, only three of the eight sites monitored met the Ministry for the Environment guidelines for water quality.

Environment Southland monitorsbacteria at recreational shellfish gathering sites once a month throughout the year. High levels of bacteria means disease-causing micro-organisms are more likely to be present, meaning a higher risk to human health.

Two of the sites, Toetoes Harbour at Fortrose and Jacobs River Estuary, returned seasonal results well in excess of Ministry for the Environment guidelines, breaching levels in 75 per cent of samples taken.

Environment Southland coastal scientist Nick Ward said shellfish were filter feeders, meaning they were very susceptible to changes in the water around them.

The sites were both riverine-influenced, meaning they were affected by what comes down through the river catchment feeding them, he said.

There were two branches of contaminants that could affect shellfish, toxicants such as metals, pesticides and chemicals, and microbiological agents, such as bacteria and viruses, he said.

Environment Southland does not monitor the shellfish themselves, rather the water they live in. When the water results show high levels of contaminants the chance of getting sick from consuming the shellfish was higher.

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