Figure 11. — Lightweight refrigeration unit for cooling water in holding tanks. 



the acceptability of the polyvinyl chloride tag 

 and that of the Vaseline-pigment secondary 

 mark. 



Richard A. Neal, Project Leader 



POSTLARVAL AND JUVENILE SHRIMP 



We have learned that abundance indices of 

 the postlarval and juvenile life history stages 

 of brown shrimp can be used to predict the 

 subsequent abundance of adults. The juvenile 

 index is more reliable, but predictions based 

 on postlarval indices have a greater potential 

 value because infornnation is available about 

 2 months sooner. In 6 of the 7 years for which 

 data are available, indices of abundance of 

 juvenile brown shrimp, developed from Galves- 

 ton Bay bait shrimp fishery statistics, have 



Table 6. --Comparison of the survival time of shrimp marked with 

 biological stain and with biological stain plus fluorescent pigments 



portrayed the general magnitude of the adult 

 brown shrimp harvest along the entire Texas 

 coast. 



Postlarvae 



Systematic sampling for innmigrating post- 

 larval shrimp continued at Galveston and at 



16 



