optimum Sustainable Yield 



One of the most important management 

 principles set out in the law is that manage- 

 ment plans should result in optimum yield. 

 Optimum yield, according to the broad defini- 

 tion in the Act, is the allowable catch which 

 (A) will provide the greatest overall benefit to 

 the Nation, with particular reference to food 

 production and recreational opportunities; 

 and (B) which is determined as such on the 

 basis of the maximum sustainable yield (MSY) 

 as modified by any relevant economic, social, 

 or ecological factors. 54 



Implicit in optimum yield is the idea that 

 the concepts and data from all the fields indi- 

 cated in the Act should be integrated and not 

 treated as separate entities. Management plans 

 based on the finest concept will do little good 

 if their implementation results in dangerous 

 depletion of the fish stocks or massive social 

 disruption with attendant political agitation. 

 Unfortunately, integration of biological, 

 economic, and social information poses major 

 problems. 



In the past, it was considered adequate to 

 analytically determine the total allowable 

 catch that each species could sustain without 

 damage to the parent stock. That figure was 

 known as the maximum sustainable yield 

 (MSY). However, most fishery experts would 

 now agree that MSY cannot be determined for 

 any species because there are too many 

 unknown biological factors which influence 

 the size and health of fish stocks. This situa- 

 tion is further complicated by the traditional 

 common-property nature of fish resources 

 and incomplete knowledge of the entire 

 marine ecological system. 



In addition, social and economic factors are 

 of considerable importance in a free society 

 and do, in fact, have a major effect on actual 

 utilization of each species. The concept of op- 

 timum as opposed to maximum (or "best" as 

 opposed to "most") is to take these social and 

 economic factors into consideration. 



Like an MSY figure, a precise optimum- 

 yield figure for each fishery is not attainable at 

 this time. However, a process can be sought 

 for considering all factors and reaching a com- 

 promise set of guidelines to follow for good 

 management. 



Such optimum yield concepts should be 

 adaptable to changes in resource priorities, 

 knowledge about the resource, information 

 about its use, and the trade-offs that result 

 from management. Optimum yield is the core 

 of each management plan which will probably 

 include such other items as: quantities and 

 types of fish to be harvested; methods and 

 techniques to be used; and measurements and 

 evaluations to be conducted. 



No specific process for seeking optimum 

 yield for a fishery has been established yet. 

 The yield figures used by the National Marine 

 Fisheries Service in drawing up preliminary 

 management plans are estimates based on ex- 

 isting data, which is mostly biological in 

 nature. However, NMFS and the Regional 

 Councils are wrestling with the problem of 

 how to pursue optimum yield. A workshop of 

 council members and Federal officials is being 

 planned for purposes of devising a method of 

 seeking the optimum yield for each fishery. 

 New concepts need to be developed and much 

 new information must be gathered in order to 

 obtain an integrated view of the fisheries of 

 the United States and to determine the op- 

 timum yield of a fishery. In the meantime, it is 

 clear that at least the following factors should 

 be considered: 



62 



