Figure 1— Hypothetical 

 Production Function. In this case, 

 the function has a flat region 

 where average production is 

 insensitive to the amount of 

 fishing effort This occurs for 

 many populations when the 

 effect of growth and natural 

 mortality on production are 

 almost in balance. But 

 eventually excess fishing effort 

 reduces the size of the 

 population to the point where 

 recruitment fails, and production 

 drops precipitously. 



EVALUATING FISHERY 

 RESOURCE LEVELS 



To evaluate the level of use of a fishery 

 resource (i.e., underutilized, overutilized, or 

 fully utilized) we must see how the existing 

 fishing effort compares with the effort nec- 

 essary to achieve LTPY. To do this, it is 

 useful to compare CPY with LTPY and to 

 compare RAY with both. 



In this report, a fishery resource is de- 

 fined as fully utilized when the amount of 

 fishing effort is about equal to the effort 

 needed to achieve LTPY. For fully utilized 

 fisheries, the RAY and CPY are usually 

 about equal. In most cases, LTPY and CPY 

 are also about equal, but they may differ 

 as a result of production variability. 



A fishery resource is considered over- 

 utilized when more fishing effort is used 

 than is necessary to achieve LTPY. When 

 RAY is greater than CPY, and CPY is less 

 than LTPY, overutilization is indicated. Ad- 

 ditionally, it is possible for RAY, CPY, and 

 LTPY to be about equal while the fishery 

 resource is overutilized. This occurs when 

 adding more fishing effort adds very little 

 to the catch. In such cases, overutilization 

 may not have an apparent adverse effect 

 on production, but it further reduces the 

 size of the population, and it wastes effort 

 and economic resources. 



A fishery resource is termed underuti- 

 lized when more effort is required to 

 achieve LTPY. This situation is generally 

 indicated when RAY is less than CPY and 

 CPY is greater than LTPY. But there may 



be exceptions. For example, RAY may be 

 held below CPY and LTPY to compensate 

 for uncertainty in population estimates. 



These are some of the factors NMFS 

 considers in determining the degree of uti- 

 lization of a resource, but they do not give 

 a complete picture. Therefore, the NMFS 

 has used its judgment to classify fishery 

 resources as underutilized, fully utilized, or 

 overutilized whenever there is sufficient in- 

 formation. 



This report serves as only one informa- 

 tion source on the status of LMR's. Another 

 source is the guidelines set under the Mag- 

 nuson Act that require FMP's define "over- 

 fishing" in a measurable way. Magnuson 

 Act guidelines allow considerable flexibility 

 in the formulation of FMP overfishing defi- 

 nitions. Annual evaluations will determine 

 if fishery resources are overfished accord- 

 ing to these definitions. Determinations of 

 the degree of utilization reported in this 

 document are more narrowly based on 

 traditional principles of fisheries science. 

 The terms "overutilization" as used in this 

 document and "overfishing" as used to 

 fulfill Magnuson Act requirements are not 

 interchangeable. 



This document also reports on marine 

 mammals and sea turtles that are pro- 

 tected under the Marine Mammal Protec- 

 tion Act (MMPA) and/or the Endangered 

 Species Act (ESA). The same scientific 

 principles apply to the population dynam- 



