Recreational Shellfish Gathering Water Quality


Water quality monitoring for the purpose of assessing the suitability of microbial water quality for recreational shellfish gathering was undertaken at a number of popular recreational shellfish gathering sites during the 2005-06 summer. This monitoring was done concurrently with the marine recreational bathing water quality programme.

This programme involved testing concentrations of faecal coliform bacteria in coastal waters at popular shellfish gathering sites. Seventeen individual sites were monitored at weekly intervals for up to 12 separate occasions from late November 2005 to mid February 2006.

Guidelines for Recreational Shellfish Gathering Water Quality

The guideline for recreational shellfish gathering water quality is a median faecal coliform count not exceeding 14 per 100 ml over a shellfish-gathering season and not more than 10% of samples exceeding 43 per 100 ml. Non-compliance with either of these parameters indicates that the water is not suitable for the purpose of recreational shellfish gathering.

Summary of Results

The results from the 2005-06 monitoring programme indicate that water quality at most areas sampled did not comply with the water quality guideline for recreational shellfish gathering, shown in red in the table below.

Area Median FC
(per 100ml (MPN))
% of samples exceeding 43 FC per 100 ml No. of Samples Collected Guideline compliance
Ngunguru 15 17 12 Fail
Oakura - mid 4 18 11 Fail
Oakura - north 6 17 12 Fail
McLeod Bay 7 17 12 Fail
Taurikura 3 25 12 Fail
Urquharts 1 33 12 Fail
Pataua 30 42 12 Fail
Waitangi 6 0 12 Pass
Te Haumi River 2 0 12 Pass
Tinopai 300 58 12 Fail
Kelly's Bay 5 25 12 Fail
Ruakaka 4 9 11 Pass
Mangawhai 8 36 11 Fail
Pahi 17 27 11 Fail
Taipa 2 9 11 Pass
Coopers Beach 9 36 11 Fail
Cable Bay 4 27 11 Fail

Of the 17 sites sampled four sites exceeded the median faecal coliform limit of 14 per 100 ml and 13 sites had more than 10% of samples that exceeded a faecal coliform count of 43 per 100ml. Four sites; Ruakaka at surf club, Te Haumi River, Waitangi Bridge and Taipa, had 100% compliance with the water quality guidelines for recreational shellfish gathering in the 2005-06 season.

It is acknowledged that these results are indicative only, as they were not collected over an entire shellfish-gathering season (which would be year round in Northland) and more samples are required to have reasonable certainty in testing for compliance with the standard. Nevertheless, these data provide a reasonable snapshot of the suitability of water-quality for recreational shellfish gathering purposes in the areas assessed.