Figure 1. — The holding tank, baffles, and filters used in shrimp marking experiments. 



Figure 2. — Aeration unit and siphon filler-drain nozzle 

 through which water enters tank. 



plate of the cooling tank, consists of a piece of 

 0.6-cm (0.3-inch) diameter stainless steel tubing, 

 20.3 cm (8 inches) long, and is sealed at one 

 end. The top of the chilling tank is reinforced 

 by a 30.5 by 30.5 cm (12 by 12 inches) frame 

 made from angle aluminum stock 3.8 by 3.8 by 

 0.6 cm (1.5 by 1.5 inches by 0.25 inch). 



Two experiments were completed to deter- 

 mine the cooling capability of the unit. Water 

 was recirculated through the chilling unit at 

 rates of 114 to 132 liters (30 to 35 gal) per 

 min, and thermographs recorded water and air 

 temperatures (Fig. 5). The temperature at- 

 tained after 24 hr was about 15.6° C (60° F) 

 and was lower than that required for shrimp- 

 marking procedures. Field observations have 

 indicated that water temperatures can be main- 

 tained within 2° C (4° F) of desired levels, ir- 

 respective of fluctuations in air temperatures. 



A table top with plastic pans 33.0 cm (13 inch- 

 es) long, 38.1 cm (15 inches) wide, and 13.97 

 cm (5.5 inches) deep equipped for continuous 

 water circulation (Fig. 6) slides over the lip 

 of the holding tank and extends about 5 cm (2 

 inches) beyond the ends of the tank. When in 



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