COMMERCIAL YIELD (millioni of pound!, htadi-on) 



JV/^ 



LV.^^- P 



,/v< 



/^\ / 



1956- I960 



Analysis of commercial pink shrimp statistics, 

 Obregon-Campeche grounds, 1956-1960. 



of the population ordinarily vulnerable to the gear employed, and interpreta- 

 tions given analyses of associated statistics apply only to members occupy- 

 ing the upper size or age strata. 



Involving only the population phases composed of pink shrimp equiv- 

 alent to 19-24 count size (heads-on) and larger, a plot of monthly biomass in- 

 dices for the period 1956-1960 yields the seasonal abundance curve typical of 

 Gulf shrimp populations (see figure^ B). Its amplitude of relatively low order 

 can be attributed to the fact that landing statistics pertained solely to older 

 population segments, the curve in no way reflecting actual status of the great- 

 er part of pink shrimp aggregations occupying the grounds. Thus, the most 



24 



