Background
- Larval decapod (Image:Anita Slotwinski/TAFI)
Australia is depauperate in zooplankton time series. Globally there are zooplankton times series spanning more than 15 years in no fewer than 30 countries, including many relatively small and developing nations. The Sir Alister Hardy Foundation for Ocean Science (SAHFOS) has the longest marine biological dataset that has been monitoring plankton in the Northern Hemipshere since 1931. However, the longest ongoing times series in Australia is 2 years and consists of a single cross-shelf transect. Given its diversity of marine habitats and the economic and social importance of fishing, Australia is clearly impoverished in long-term zooplankton datsets. The Australian Continuous Plankton Recorder (AusCPR) project will help redress this situation by providing estimates of plankton abundance monthly along the east coast of Australia and between Australia and Antarctica.
- Sir Alister Hardy deploying one of the first CPR instruments
History of the Continuous Plankton Recorder
On the Discovery expedition of the Antarctic in 1926, Sir Alister Hardy collected continuous records of phyto- and zooplankton abundance that showed dramatically the patchiness of plankton in the Southern Ocean. He called the new sampling device the "Continuous Plankton Recorder" (CPR) and it remains in use and virtually unchanged to this day (left). This extremely robust and durable device is towed monthly near the surface over extended transects (1000s km), collecting plankton on a filtering silk.
The AusCPR survey builds on the success of the 'mother' CPR survey run by the Sir Alister Hardy Foundation for Ocean Science (SAHFOS) which is based in Plymouth, Uk. The marine monitoring program has been collecting data in the North Atlantic and North Sea on the ecology and biogeography of plankton since 1931, and is one of the longest biological marine time series in the world. The unique marine biological dataset has provided a wide range of environmental and climatic indicators used by scientists and policy makers to address marine environmental management issues such as harmful algal blooms, pollution, climate change and fisheries. SAHFOS has successfully collected and archived over 170,000 plankton samples on a monthly basis since 1946 in the North Sea and North Atlantic Ocean through this practical and cost-effective methodology.
Ships of Opportunity
The strength of the CPR lies in its unique ability to collect samples frequently over large spatial scales. This is possible because the CPR is a simple, robust device that can be towed behind ships of opportunity (SOOPs) on their normal trading routes at their conventional operating speeds, usually 15–20 knots, unaccompanied by research staff. Other large-scale surveys are often conducted as part of fish stock surveys (because of cost constraints) and are thus usually conducted annually, whereas samples that are collected frequently (weekly– monthly) are usually point samples taken close to the coast where they are subject to local coastal processes. Sampling from SOOPs is so cost effective that it is now spawning new satellite surveys.
Other CPR Surveys
In addition to the 'mother' North Atlantic CPR survey (pictured below) and the AusCPR survey, there are 3 other CPR surveys: viz. North Pacific, Northwest Atlantic and Southern Ocean. The North Pacific survey, operated from the Sir Alister Hardy Foundation for Ocean Science (SAHFOS) in the UK, has been running since 2000 and samples down the west coast of Canada and the US, and between the US and Japan. The Northwest Atlantic survey is operated by the Northeast Fisheries Science Center (NEFSC) USA and runs down the east coast of USA and has been operating since 1977. The Southern Ocean CPR survey has been run by the Australian Antarctic Division since 1991 (below). This survey tows mainly during the early spring to late autumn (September-April) in the Southern Ocean when research and supply vessels are operating. Occasional tows are conducted in winter when the opportunity arises.
- Spatial coverage of the CPR survey over the past 65 years in the North Atlantic (Map:Anthony Richardson/SAHFOS)
- CPR coverage in the Southern Ocean (Map:AAD)