When the CCAMLR Working Group on Ecosystem Monitoring and Management (WG-EMM) last met in Cambridge in July 2003, a major task was to hold a workshop to review the CCAMLR Ecosystem Monitoring Program (CEMP).
CEMP was established in 1984 in response to the development of a krill fishery in the Southern Ocean. The original objectives of CEMP were to (i) detect and record significant changes in critical components of the ecosystem to serve as a basis for the conservation of Antarctic marine living resources, and (ii) distinguish between changes due to the harvesting of commercial species and changes due to environmental variability, both physical and biological.
A broad framework for CEMP was initially established by selecting indicator species, including Adélie penguins, fur seals and black-browed albatross, identifying ecological parameters to be measured, developing standard methods for measurement of parameters, and establishing a network of sites around the continent and three integrated study regions across a latitudinal gradient (South Georgia, Antarctic Peninsula and Prydz Bay). Within this broad framework, a number of major monitoring and directed research programs were established by Australia, Japan, South Africa, UK and the USA, with additional contributions from Argentina, Chile, Germany, New Zealand and the former USSR. These programs have produced a number of long-term time series data sets on selected indicator species and at recognised CEMP sites.
Initial CEMP studies by Australia were undertaken in the late 1980s at Magnetic Island near Davis station. In 1990 the focus for Australia’s CEMP work shifted to the Mawson region, where the potential for overlap between the krill fishery and krill predators was greater. From 1990–91 to the present day, monitoring of virtually all of the recommended CEMP parameters for Adélie penguins has been undertaken annually at Béchervaise Island, which has provided a 13-year time series of data. In addition to the CEMP data, surveys of krill availability in the foraging range of the Adélie penguin populations nesting at Béchervaise Island have been undertaken in 2000–01 and 2002–03 to improve our understanding of how each of the parameters varies with food availability.
After some 15 years of application, and the accumulation of much scientific and practical knowledge, a review of CEMP was appropriate and timely. The time series of data were now large enough to assess the extent of natural variation and its likely causes, allowing consideration of whether a critical initial objective of CEMP, distinguishing between changes due to natural variability and harvesting, was possible. In the light of experience gained since its inception, the review also aimed to consider issues such as the strengths and weaknesses of the program in relation to the original objectives, potential additions and improvements to the existing program, the extent to which data from CEMP sites were representative of the areas in which they are located, and the ability to develop management advice from CEMP data. These issues were discussed in Cambridge at a five-day review workshop, the first in a series of WG-EMM workshops aimed toward developing management procedures for the krill fishery, which will include a revised monitoring program.
The workshop agreed that the original objectives of CEMP remained appropriate but recommended that an additional objective, the development of management advice from CEMP data, be adopted. This is an important development as it focuses the program on the problem of providing management advice.
Arguably the most important conclusion reached by those at the workshop was that, with the existing design of CEMP, it may never be possible to distinguish between natural changes and those changes resulting from harvesting. This conclusion recognised the fact that there are multiple sources of natural environmental variation which could all be confounded with the effects of harvesting. The existing CEMP is also not the result of a rigorous design process but has been formed by the incorporation or development of research within national programs, usually at existing study sites, and so is not optimally configured. This has important consequences for any future CEMP, and recognises that there will always be some level of uncertainty inherent in the provision of management advice.
A second conclusion relating to the lack of an explicit design for CEMP, is that we need to know how representative CEMP sites are of their local areas and regions. Currently, most nations collect data from a single site on the assumption that changes at that site represent changes of a similar nature across a larger region. Collection of data from multiple sites in a region would be desirable, but we would need to find an appropriate balance between increasing the generality and certainty of our understanding of change, with the cost of a larger scale program.
The workshop concluded that the existing CEMP program has many strengths, which include the provision of a detailed quantitative description of Southern Ocean processes, and that data collected through CEMP were appropriate for the recording and detection of change in critical components of the ecosystem. The workshop recommended that further work on the nature, magnitude and significance of changes in CEMP parameters be undertaken, and recognised that the accumulated time series of data across several species and sites will be an extremely valuable resource in this undertaking.
Rather than completing the review of CEMP in a single workshop, CCAMLR has begun a review process that will continue over the next few years along with other CCAMLR developments, as an integrated management procedure for the krill fishery is developed. The findings of the review to date provide a focus for further strategic research, through the analysis of existing data and through the collection of additional data to fill gaps that existing information cannot address. The eventual aim of this process will be to develop a new monitoring program that is an integral component of krill fishery management procedures.
Colin Southwell, Antarctic Marine Living Resources Program, AAD