A manually operated gun with a magazine hold- 

 ing 100 tags (14 mm x 3 mm x 0.5 mm) was 

 used to insert the tags. Individually numbered 

 tags enabled us to determine species, date, and 

 location tagged, and date and location recovered. 

 The gun was designed so that approximately 

 5 mm of the tag protruded from its barrel. The 

 incision for inserting the tag was made by push- 

 ing the tag through the body wall. By holding 

 the end of the barrel against the fish and de- 

 pressing the plunger, a tag was inserted approx- 

 imately 5 mm through the body wall into the 

 body cavity (Figure 2). Tests were not per- 

 formed to determine tagging mortality. How- 

 ever, experiments on menhaden indicate a tag- 

 ging mortality — tag shed rate of 10-20% for fish 

 over 110 mm having this tag.' 



Thread herring were tagged aboard menhaden 

 carrier vessels. Fish were dipped from the purse 

 seine, placed in live boxes (2 ft X 2 ft X 4 ft) 

 supplied with running seawater, tagged, and im- 

 mediately released overboard. Each box held 

 200-500 thread herring (average 150 mm fork 

 length) for as long as 45 min. Fish did not 

 exhibit overexcitement or die when held in these 

 numbers. Water temperature was 23°C. 

 Average recovery efficiencies and the range of 

 efficiencies are shown for each recovery area by 

 year in Table 1. All recovery efficiencies were 

 calculated from recoveries on primary magnets 

 except the Fernandina Beach, Fla., area in 1968. 

 Only one tag was recovered there on a secondary 

 magnet. Using the average recovery efficiencies, 



^ Kroger, R. L., and R. L. Dryfoos. Preliminary tag- 

 ging and tag-recovery experiments with Atlantic men- 

 haden, Brevoortia tyrannus. Manuscript in preparation. 

 National Marine Fisheries Service, Atlantic Estuarine 

 Fisheries Center, Beaufort, NC 28516. 



Figure 2. — Close-up of thread herring being tagged. 

 Inset: Stainless steel tag. 



we estimated the total number of tagged fish 

 recaptured from our field tagging (Table 2). 



Movements 



Directions of the movements of fish were de- 

 termined from recaptures of tagged thread her- 

 ring (Figure 3) . In the South Atlantic the men- 

 haden fishing fleets operate near the processing 

 plants, and catches are landed on the same day 

 they are caught. A daily inspection of magnets 

 enabled us to determine the area and date of 

 tag recapture. 



In 1968 an estimated 92 tagged fish were re- 

 captured. Twelve of these tagged fish were re- 

 captured near Southport, N.C., about 75 miles 

 south of the release site within 25 days after 

 release. Two months after release, the fish had 

 migrated about 370 miles south to Fernandina 



Table 1. 



-Tag recovery efficiencies by year and location where tagged thread herring 

 were recovered, 1968-70. 



298 



