Defining smaller management areas within CCAMLR

This paper discusses the principles required to develop of small-scale management units and highlights a work program in this development. It provides the theoretical foundation for considering the scales of management units involving the integration of local populations of harvested species, foraging areas of predators, fishing grounds and the potential influences of the environment, including oceanography and metapopulation structure of the harvest species. The integration of these three components requires two different units: the “harvesting unit”, which is at the scale of the metapopulation of the harvested species, and the “predator unit”, which does not have to be a relatively self-contained ecosystem but should be sufficiently self-contained such that fishing in that unit does not inadvertently affect predators being monitored in other units. Harvesting units are defined and a number of additional divisions of CCAMLR statistical areas are proposed on ecological grounds to complete the division of the CCAMLR area. The South Atlantic region (Area 48) is used to illustrate how to define predator units. The derived conceptual model is then used to formulate a work program for the development of fisheries on prey species, notably krill, in other harvesting units. The manner in which predator units can be used to help the CCAMLR Ecosystem Monitoring Program provide strategic advice on the effects of fishing is discussed. In general, the early acquisition of information from within a harvesting unit on the distribution of local populations of krill, the potential foraging density of predators (i.e. abundance of predators, distribution of colonies and foraging range) and the potential fishing grounds will provide the means for circumscribing predator units as well as undertaking an assessment of long-term annual yield. It is proposed that the early development of the fishery could be concentrated in a small number of units to the extent that the fishing intensity in those units is equivalent to the intensity expected across all units once the TAC had been reached. Other units in which fishing was not occurring could be monitored as well. This process could help predetermine whether or not the TAC is likely to cause undesirable effects on predators in any of the predator units. In this way, the need for whether or not local restrictions on harvesting are necessary can be determined well in advance of the TAC being reached as well as the overall requirements for the monitoring program.