H-50 

 PRACTICAL IMPLEMENTATION OF THE RESEARCH PROGRAMME 



3.1 .2 Microscale studies on the ecology ofkrill swarms 



The interaction between phytoplankton composition and biomass and the swarming of 

 krill under the influence of oceanographic factors can be studied at the rate of 10 km per 10 

 days; two to three ships are needed in a complete experiment of this type. Measurements to 

 provide information on vertical transport and stability and on advection should be made, and 

 samples taken in order to determine the spatial distribution and densities of swarms of krill in 

 relation to the abundance and size spectra of phytoplankton, which will enable us to 

 understand the reactions of a krill swarm to its food base and the effects of grazing on the 

 phytoplankton. Quantitative recordings and sampling for analyses of phytoplankton 

 distribution and zooplankton abundance and composition in different depth layers and at 

 different times of day and night will provide additional information on the spatial structure of 

 the biotic environment of krill. Echo sounding and sonar observations should provide 

 three-dimensional pictures of the changes in time of zooplankton concentration. 



These studies should be carried out at several selected places, mainly in areas of high kriU 

 concentration at the ice edge, in the neritic zone of the Antarctic Peninsula and of the 

 Antarctic islands, as well as in the open ocean of the West Wind Drift, the East Wind Drift and 

 the upwelling zones. If possible the studies should be repeated at different times of the year. 



3. 1 .3 Microscale studies of food chain structures and functions 



In order to learn more about possible future effects ofkrill fishing on the structure of the 

 first and second trophic levels, the composition of phytoplankton and its productivity should 

 be studied in places and seasons which differ in relative abundance of krill, salps or other 

 herbivores. These studies must be based on quantitative plankton sampling at various depths, 

 and can be considered as an extension of 2.2.2 into areas and seasons where alternative grazing 

 and predation strategies lead to changes in the quantitative composition of the herbivore level. 



3.1 .4 Macroscale studies of zooplankton, nekton and benthos 



There is still a need for further quantitative sampling of zooplankton, pelagic squids and 

 fishes in various regions of the Southern Ocean, and the benthos of the Antarctic is poorly 

 known. Quantitative data are needed on the abundance of the dominant elements of plankton 

 and benthos in the different regions. The position of the dominant species within the food 

 chains should be ascertained by studies of stomach contents and feeding apparatus. Benthos 

 studies may be combined wath observations on sedimentation and decomposition of fecal 

 pellets, dead zooplankton, particularly krill, and diatoms. The biological and sedimentological 

 surveys are very time consuming, and more than one research vessel will be needed, even if the 

 intention is to cover only one oceanic sector each summer. 



3.1.5 Seagoing activities of other vessels 



The seagoing research tasks require the co-operation of a number of oceanographic and 

 other vessels in the Southern Ocean. The majority of the seagoing studies need fully equipped 

 research vessels, particularly the multidisciplinary studies on the relationship between krill and 

 the environment. The success of the biological programmes will depend largely on good design 

 and effective integration with physical studies of horizontal transport and vertical mixing. It 

 would neither be sufficient nor economical to add small biological programmes to physical 

 expeditions and vice versa, but full scale programmes of both disciplines could be combined. 

 International co-operation is essential in view of the large support needed for a 

 multidisciplinary study which includes several vessels and a considerable number of speciahsts. 



