Whitianga marina – baseline ecological survey and on-going monitoring

Purpose: Baseline ecological survey and monitoring for resource consent. The initial report provides a pre-impact baseline for which to measure possible marina effects. It includes a description of biological community structure within Whitianga harbour with an emphasis on sandy intertidal shellfish and seagrass communities. Analysis of harbour waters for concentrations of bacteria and selected heavy metals associated with antifouling compounds is undertaken, as well as analysis of pipi for concentrations of faecal coliforms, total petroleum hydrocarbons and selected heavy metals.

36 sites covering approximately 1km of coast, intertidal and subtidal. Species lists Quadrat counts Species occurrence and dominance along transect lines Descriptive transects on eastern side of harbour Water sampling for heavy metals and enterococci Shellfish sampling for heavy metals (copper, lead and zinc), total petroleum hydrocarbons and faecal coliforms Sediment sampling for particle size analysis

Whitianga Harbour and eastern end of Buffalo Beach

Whitianga Harbour in vicinity of marina – E2752078 N6481712, NZMG, 1:20000, AREA Eastern end of Buffalo Beach – E2751550 N6482579, NZMG, 1:10000, AREA

26 Nov – 14 Dec 1992

The pre-construction survey involved: A presence/absence species list compiled from previous studies and this study. 9 transect lines from the western shoreline to the main channel between Robinson Road boat ramp and the harbour entrance. Habitat types were sampled using randomly-placed 1m x 1m quadrats taken along transects to sample substrate type and cover-class or abundance estimates of species present. 8 mid-channel sites in the harbour – site descriptions and random quadrat data. Occurrence and abundance of selected organisms at each of the channel sites includes cockles, pipi and mussels. 7 stations on the eastern shoreline of the harbour. Used 0.5mm sieve, measured not less than 50 bivalve individuals of commercial size only. 13 cross-sectional depth profiles of the harbour were described with echo-sounding.

Not reported. The description of the methods used to undertake the ecological baseline survey is lacking in detail and would be difficult to replicate with certainty. The placing of quadrats and cores, sampling along transects, and the number of replicates within a habitat type is not clear. 'Worms' are identified to species level in the presence/absence data but are not in the quantitative quadrat data (Appendix II and III). (pers.com. M Graeme) Gaps in collection: Not reported Data quality: Biological - consistent with guidelines recommended by the Department of Conservation (1991) for 2nd and 3rd order Coastal Resource Inventories. Water sample preparation and analysis – US EPA protocol Attribute accuracy: Not reported except for water and shellfish monitoring. Smith (1993) recommends changes to the monitoring methods as sampling sediment for metals and hydrocarbons was impractical. Recommended changes include eliminating sediment sampling and substituting hydrocarbon analysis of the shellfish. Completeness: Not reported

report, electronic Digital Format: MS Word, MS Excel

Freely available Sensitivity/Confidentiality: None

The micro-organism, heavy metal and petroleum hydrocarbon analysis was undertaken by NIWA (Smith 1993). Proposes ongoing monitoring programme of quantitative sampling of sites 0, 6, 12 and 36 months after the final construction. Biological communities appear to have been relatively stable since 1986 and of high quality. Appendix VI seems to be missing from the report.