12 



MSY 



adult 



depleted 



recruit 



For the purposes of fisheries management, both of these definitions 



(21) 

 have limited utility. 



8. Stability 



Although environmental fluctuations are recognized as elements of 

 marine ecosystem stability, they are extremely long-term in effect, 



difficult to predict and far exceeded in impact by the development of 



(22) 

 sophisticated marine fisheries. Consequently, the ecosystem usually 



is treated as a stable system with regard to stock assessment. 



9. Simulation Arrangements 



"...Biological models are all static inasmuch as they convert 

 yearly figures into long-term averages. The aim is to erase yearly 

 fluctuations and to allow year-to-year comparisons so that the addition 



of all the successive yearly averages gives a systemmatic and dynamic 



(23) 

 picture of the long-term developments..." 



The general assumption here has been that interspecific trends as 



well as long-term developments would result from monitoring single 



species over time.^^' 



