40 



LANDINGS 



: FREEPORT 



<I5 



15-20 21-25 26-30 31-42 43-50 51-65 

 NUMBER PER POUND (HEADS-OFF) 



>65 



Figure 9. — Size composition of brown shrimp sampled from landings, July 1965. 



50 



40 



O30 



O20 



K 10 



15-20 21-25 26-30 31-40 41-50 

 NUMBER PER POUND (HEADS-OFF) 



51-67 



>67 



Figure 10. — Size composition of brown shrimp landings from published data, 



July 1965. 



Table 3.--A comparison of three estimates of 

 catch rates (kilograms per hour) for a 

 particular fishing area 



Comparisons of our data with the published 

 information suggest that the reported data 

 on size are satisfactory for description of 

 general trends. When more accurate infor- 

 mation is required for estimating growth or 



mortality of shrimp, we must supplement the 

 reported size data with measurements. The 

 published data on landings do accurately re- 

 flect catch rates of shrimp in areas where 

 interviews with crew members are obtained. 



James P. Clugston, Project Leader 



POSTLARVAL AND JUVENILE SHRIMP 



The abundance of postlarval and juvenile 

 brown shrimp collected near Galveston, Tex., 

 has been used for the past 6 years to estimate 

 offshore supplies of adult brown shrimp. Our 

 indices of abundance for the two younger 

 stages and the monthly catch of adult brown 

 shrimp along the Texas coast are shown in 

 figure 11. The initial occurrence ofpostlarvae 

 and the duration of their movement into 

 Galveston Bay vary from year to year, but 

 peak numbers ordinarily are found between 

 mid-March and mid-April. Often August or 

 September has a second smaller peak. The 

 strength of the year class is correlated with 



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