II. STOCK ASSESSMENT INFORMATION REQUIREMENTS^^^'^^ '^^'^^^ 



In order to understand various fisheries populations, assessment 

 science seeks to meet the following parameters: 



1. Determination of the Unit Stock ; i.e., the extent to which a fish 

 population and the fishery based on it can be treated as a unit system 

 (necessary for the purposes of calculation). This unit stock is determined 



by 



• Distribution of the species 



• Identification of spawning areas 



• Age composition data .q, 



• Morphological and physiological characteristics ^^^ 



2. Population Parameters of that Unit ; i.e., the size and age composition 

 of that unit stock. 



• Rate of growth and source of food 



• Food requirements 



• Natural mortality 



• Age of recruitment 



• Basic productivity 



3. Effects of Environmental Factors on Stocks 



• Temperatures 



• Bottom conditions 



• Currents 



t Seasonal changes 



• Pollutants 



Effects of Human Activities on Stocks 



• Catch-effort coefficient, i.e., the amount of effort necessary to 

 harvest a portion of the population 



