condition. A box found suitable for holding 

 large numbers of live shrimp aboard a vessel 

 is shown in figure 2, Box size may be modi- 

 fied according to available deck space, and it 

 will ordinarily be best to carry two boxes 

 of equal size — one on each side of the vessel 

 to prevent undesirable list. On small vessels 

 where extra weight may create a problem, 

 the amount of water carried in the boxes can 

 be decreased without materially altering the 

 usefulness of the holding box by merely 

 lowering the height of the overflow hole. 



All water should be screened before it is 

 piped into holding boxes. A coarse filter 

 placed at the intake and a fine-mesh filter 

 inserted in the water supply line just before 

 it connects with the holding box adequately 

 serve this purpose. With about 15 pounds' 

 pressure, the 1-inch pipe will deliver 6 to 8 

 gallons per minute of well-aerated sea water 

 through the four siphon filler-drain nozzles 

 (figs. 2 and 3). 



If growth rate is to be estimated from 

 stained shrimp recaptures, marked specimens 

 should be of uniform size when released. Allen 

 and Costello (1962) describe a simple yet 

 efficient sorting device adaptable to any field 

 condition. 



MASS- MARKING TECHNIQUES 

 Equipment (Shore- Based) 



Field equipment, which facilitates rapid 

 marking of large numbers of shrimp, is 

 shown set up ready for use in figure 4. It 

 consists of lightweight, portable equipment. 

 The water pump is driven by a gasoline 

 engine, so no electrical supply is required. 

 The holding box is of simpler design than that 

 suggested for shipboard use. This box (item M, 

 fig. 4) will hold 3,000-4,000 medium-sized 

 shrimp (total length, 85 to 110 mm.) 6 to 8 

 hours without excessive mortality. 



TOP VIEW- DETAIL OF BOX 

 BOTTOM WITH 

 SCREENING OFF 



*4 NIPPLE 



EXIT OF V PLASTIC 

 AIR VENT HOSE 



jbj ]\ n, ^ 



WATER ENTERS HERE 

 THROUGH I" PIPE 



TO WATER PUMP 



5/4* PLASTIC AIR VENT HOSE 



V«" PLASTIC FRICTION TYPE 'T' 



3,^ MARINE PLYWOOD 



2"« 4" FIR 



3' O VERFLOW HOLE. 

 SCREENED WITH '/« 

 HARDWARE CLOTH 



. I DRAIN HOLE 



AIR VENT 

 HOSE EXIT 



J,4 MARINE 

 PLYWOOD 



SCREEN FRAME 



.5 



00^5^-^ 



2'«4' FIR 



36- 



— 2i4 FIR 



SHRIMP HOLDING BOX 



END VIEW - SCREENED 

 (S«fl ScfMn DataJI Owg) 



Figure 2.— Shrimp holding box suitable for use at sea. A box of these dimensions will hold 6,000-8,000 shrimp 

 (85 to 110 mm. total length) for several days if the temperature is maintained between 60° and 75° F. 



