Equipment (Shipboard) 



Adaptation of shore-based marking equip- 

 ment for use aboard a vessel involves attach- 

 ing large items securely to the deck. In 

 inclement weather, baffles should be placed 

 in shrimp-holding boxes to minimize any 

 injury the shrimp might receive from surging 

 water. 



Staining Instruments 



Tuberculin syringes of 1/2 or 1 cc. capacity 

 and fitted with 1/4-inch hypodermic needles 

 are used for staining. Thirty-gauge needles 

 have proved best for injecting stain into all 

 sizes of shrimp. Small-gauge needles cause 

 little tissue damage at the injection, sites. 

 Their use also reduces dripping of low- 

 viscosity staining solutions between injections 

 and measurably speeds the staining process. 



Staining Procedure 



As live shrimp are received for marking, 

 they are placed in the large holding box 

 (M, fig. 4). If grading is required, it precedes 

 the marking operation. The shrimp are placed 

 in the shrimp-grading device (L) suspended 

 in the large holding box. Ungraded or graded 

 shrimp are dipped, a small number at a time, 

 into the table trays (D). After injection, 

 marked shrimp are tossed into the trough 

 of running sea water (E) where they are 

 carried to holding cage (B). 



Stains may be injected into shrimp through 

 the articular membrane of either the fifth or 

 the sixth abdominal joint with the former 

 being the preferred site (fig. 5). Very small 

 shrimp (60 mm. total length or smaller) are 

 more easily marked by injecting the stain 

 laterally through the sclerite of the first 

 abdominal segment (fig. 6). 



Dawson's (1957) description of the proper 

 method of handling shrimp for injection Is 

 quoted as follows: 



Holding the syringe in the right hand, a shrimp was 

 grasped with the left so tliat its head was pointed 

 toward the left wrist and with its abdotnen held in a 



Figure 5. — Injection through articular membrane of 

 fifth abdominal joint is recommended for shrimp 

 longer than 60 mm. total length. 



Figure 6.— Injection laterally through sclerite of first 

 abdominal segment is recommended for shrimp 

 shorter than 60 mm. total length. 



flexed position by tiie left thun* and forefinger. The 

 needle was then introduced through the articular mem- 

 brane of the sixth abdominal joint slightly to the left 

 of the middorsal line and at an angle approximating 

 45 degrees. The needle was inserted to a depth of 

 from 2 to 4 millimeters until stain was visibly entering 

 the blood-vascular system through the dorsal abdominal 

 artery. 



Care should be taken not to puncture the 

 hindgut when the hypodermic needle is in- 

 serted. Also, injection of air in the form of 

 minute bubbles during the staining process 

 will cause shrimp mortality. This problem 

 can be eliminated by holding the syringe and 

 needle in a vertical position (needle up) for a 

 moment after the solution is drawn and forcing 

 out any visible bubbles by slight pressure on 

 the plunger. 



