Historical extent of mussel beds in the Firth of Thames

Substantial green-lipped mussel fisheries used to operate in the Hauraki Gulf and the Firth of Thames. These fisheries, and their eventual sharp decline and collapse, were summarised in a fisheries technical report (Reid 1968), and a scientific paper (Greenway, 1969). Included in these works are maps of mussel distributions from the 1960s and earlier. Purpose: To identify the historical extent of green-lipped mussel beds in the Firth compared to today.

Distribution of mussel beds in 19 60s.

Firth of Thames

Firth of Thames – 2725589, 6453054, NZMG, 1:20,000, AREA

1960s and earlier

Based on published literature of fisheries catch data. Frequency of collection: One off review of literature.

Not reported Gaps in collection: Not reported Data quality: Not reported Attribute accuracy: Not reported Completeness: Not reported

reports, maps Digital Format: GIS (ArcView)

freely available - Digitised shape files for the historical extent of mussel beds in the Firth of Thames are held by DoC - Jason Roxburgh (FOT only) and Clinton Duffy (HG and FOT combined). Sensitivity/Confidentiality: None

Complete

Additional comments: As part of the Seafloor acoustic mapping of the Hauraki Gulf, NIWA scanned and overlaid the 1960s mussel distribution maps as spatial coverage on the current acoustic survey information. Ground-control points were used to correct the image to real-world coordinates, although some inconsistencies with the coastline data remain (due to different resolutions and scales used). Related information: DoC Firth of Thames/Hauraki Gulf seafloor acoustic mapping