New Zealand CPR Survey

Karen Robinson - Plankton Analyst, NIWA

The New Zealand CPR Survey is being managed by the National Institute of Water and Atmospheric Research (NIWA). Currently two regular CPR routes are being sampled which are providing data for areas previously under-sampled.

Analysis is carried out in the NIWA laboratory in Christchurch with a Phytoplankton Colour Index score being recorded as a measure of phytoplankton biomass, and all plankton in five nautical mile segments being identified to species level where possible. These data are combined with environmental parameters collected by the ship's underway monitoring equipment during the tows to provide an overall view of plankton ecology and dynamics.

Map showing the Chatham Rise CPR survey routes

The Chatham Rise Survey

The Chatham Rise is a relatively shallow underwater plateau located to the east of New Zealand. This area is oceanographically complex, being a dynamic frontal zone between subtropical and subantarctic surface water masses. As a result it is a highly productive area that has been extensively studied, and has two permanent biophysical moorings situated north (subtropical water), and south (subantarctic water), of the Rise which record in situ environmental parameters.

The first dedicated CPR tow across the Chatham Rise was carried out in 2007 as an addition to an existing long term research program carried out by NIWA with funding from the Ministry of Science and Innovation (MSI). This research provides the opportunity for repeatable runs on a regular basis, and also produces detailed data on biological and environmental variables between the moorings. Population dynamics within the convergence zone have been shown to be complex and the CPR Survey should add valuable data on species variability.

Two routes have now been established (see map below) . Sampling occurs twice a year in spring and autumn. Analysis of these surveys is in the initial stages, with three out of nine sets of silks completed. Data obtained from the CPR will contribute to the GACS database, and will provide a benchmark for surveys in this region.

Map showing the Southern Ocean CPR survey routes

The Southern Ocean Survey

The Southern Ocean Survey was established in 2008 through funding from the Ministry of Fisheries, (MFISH) and Land Information New Zealand (LINZ) in order to map the changes in the quantitative distribution of epipelagic plankton in NZ's Economic Exclusion Zone, transiting to the Ross Sea, Antarctica. This survey carries out annual tows between 44°S and 70°S during the Austral summer. The Survey was set up for a period of five years and utilises a commercial fishing vessel, the San Aotea II, run by Sanford Ltd. The route will provide valuable data on the spatial and temporal changes in plankton communities in an area sensitive to global climate change, and will extend the range of data currently available in the Southern Ocean region which is concentrated south of Australia. The data from this Survey will contribute to the SCAR SO - CPR Survey overseen by the Australian Antarctic Division and also the CCAMLR's Ecosystem Monitoring Program C-EMP.

 To date, three years of sampling have been carried out. Twenty two tows have been collect with 12 silks processed and analysis on the latest set of tows is about to begin. Preparation is currently underway to ready the CPR for the 2011-2012 summer sampling run.

As the NZ-CPR Survey is still in the early stages of CPR collection and analysis, few trends can be presented. However for the Chatham Rise, results have already shown distinct changes in populations directly attributed to the position of the frontal zones, as well in timing and positions of blooms. The Southern Ocean Survey has also provided evidence of zonal population changes as well as population diversities similar to that recorded by other SO-CPR sections.