F-24 



of 1t10 primaxy production is estimated as 10 000 

 does not appear in the literature any firm figure 

 by Euphausiids although a 10^/ figure has been use 

 (1974) estimate that in growing to I.5 g an indiv 

 gives a conversion ratio of lt40, but since this 

 achieve a maximum size the mean population figure 

 ally used \J . On the basis that krill represents 

 ous zooplankton, the production figures ralculate 



million ton/year (Oulland 1970), There 

 for the conversion rate of phytoplankton 

 d (Oulland I970) . Chekunova and Rynkova 

 idual consumes 60 g of phytoplankton. This 

 is an average figure for an individual to 

 may well be nearer the 1:10 ratio gener- 

 between 10 and 50^ of the total herbivor- 

 d are given below; 



Estimates of krill production (millions of tons per annum) calculated on the 

 basis of total primary production of 10 000 million ton per annum. 



Calculations of the amount of krill eaten by whales have been made by several authors 

 and more recently the same calculation has been made based on the estimated initial whale 

 stocks to give an estimate of "surplus" krill. 



Independent estimates of krill consumed by whales are given in Table 6.8. 



Laws (lnp?8BB)has also estimated the amount of krill consumed by Crabeater, Leopard, 

 Ross and Fur Seals at 53 920 thousand tons each year of which about 99^^. is taken by the 

 Crabeater Seal . 



Estimates of krill conuumption by birds have been made by Provost (in press) and 

 Croxall (pers. comm.). Both agree that the major consumer is the Adelie Penguin 

 ( PygOBcelis adelie )which it is estimated takes about two-thirds of the 14-7 to ?0.3 million 

 tons total eaten by birds. 



There are no estimates in the literature for krill consumption by other groups such as 

 fish and Brpiid although it is quite likely that either or both could be major consumers. 

 Laws (in pre^)eBtimates that sperm whales consume annually 4.6 million tons of scjuid which, 

 assuming they feed predominantly on krill and assuming a ten to one conversion ratio, would 

 account for 46 million tons of krill. The same calculation applied to the estimates based 

 on orfuid eaten by the total initial whale stocks would account for 102 million tons of 

 krill per annum. 



1/ In their paper Chekunova and Rynkova give a detailed breakdown of food consumed 

 at monthly intervals during the lifespan. In the absence of realistic size 

 frequency information it is not possible to produce a better conversion 

 ratio. 



