to each of the specific fisheries to be studied. 

 It involves a large computer program which 

 provides a framework for studying short term 

 and long term effects of alternative regulatory 

 policies on economic and biological performance 

 of various sectors of a fishery. The basic program 

 is written in a version of FORTRAN IV. A 

 schematic of the basic model is shown in Figure 

 1. The sectors simulated by the program are: 

 products, markets, processors, harvesters, regu- 

 lators, stocks, and locations. General operation 

 of the model is as follows. The stock sector 

 "gi'ows" the resources and determines the 

 amount of each stock which is available for 

 harvest in each location. Harvesters operate in 

 locations of their choosing, catch a portion of 



the available stock, and sell it to processors. 

 Processors convert their purchases into finished 

 goods and offer them for sale in the markets 

 which are available. Demand (and the marketing 

 activity of the processors) determine sales by 

 each processor of each product in each market. 

 The regulators are free to impose restrictions 

 of various types on the activities of both 

 processors and harvesters. In operation the 

 program compiles statistics on the operation of 

 the system and prints out monthly and annual 

 summaries of these statistics. The detail of the 

 printout is optional. 



Each harvesting group operates as a semi- 

 independent unit, constrained only by links to 

 a location and one set of processors. At the start 



Product 

 Sector 



Consumer 

 Market Sector 



Processor 

 Sector 



Harvester 

 Sector 



Location 

 Sector 



Stock 

 Sector 



Regulator 

 Sector 



Stock 

 1 



Regulator 

 1 



Harvester 



Stock 

 2 



Regulator 

 2 



Regulator 



Figure 1. — Structure of fishery simulator. 

 30 



