62 FTRTT AND GAME COMMISSION 



2. Knowledge of the species and fishery. 



3. Continuous observation of abundance. 



4. Catch statistics. 



In applying this program, a piece of information gained does not 

 fit neatly into one of the four pigeonholes but usually applies to or is 

 useful in an understanding of more than one of the categories outlined. 



Studies of the supply approximate a census by picturing relative 

 abundance from year to year by one or both of the following : 



a. Return in catch per unit of fishing effort. 



Involves character, amount and intensity of fishing effort. 



b. Departures from normal proportion of size or age classes 



in the fish population. 



Studies of the species should determine : 



a. One uniform population or more than one local race. 



Racial studies 

 Migrations 



Tagging 



Sampling 



b. Spawning. 



Season, areas, intensity 



c. Growth rate. 



Age at sexual maturity 

 Mortality rate 



d. Abundance of each entering age class. 



A plan for continuous observation of abundance depends upon the 

 character of the fishery and knowledge of the species but is usually 

 a simplification of methods developed in the studies of relative 

 abundance. 



Detailed catch statistics are basic in determining : 



a. Crop harvested 



b. Intensity of fishing effort 



c. Population abundance 



d. Balanced regulation of the fisherv 



o' 



Although catch statistics are mentioned last in the above outlin*^ 

 actually an adequate system for gathering accurate catch records, not 

 only to show the total crop harvested but in sufficient detail to give 

 return per unit of effort, is the first point of attack in the study of any 

 fishery and for this reason the initiation of such a system was coinci- 

 dent with the establishment of the research laboratory. 



PROBLEMS STUDIED 



Such a research plan as outlined above requires several years of 

 intensive preliminary study as well as continuous observation of the 

 fishery, so obviously it could not be applied to all of the fisheries of 



