NOTES 



ATLANTIC THREAD HERRING 



(OPISTHONEMA OGLINUM) - 



MOVEMENTS AND POPULATION SIZE 



INFERRED FROM TAG RETURNS 



Atlantic thread herring, Opisthonema oglinum 

 (Lesueur), occur from Massachusetts south- 

 ward along the Atlantic coast of the United 

 States, throughout the Gulf of Mexico, and into 

 the Caribbean (Berry and Barrett. 1963; Reint- 

 jes and June, 1961) . In the South Atlantic area 

 this species is occasionally caught by purse seine 

 vessels fishing for menhaden, Brevoortia tyran- 

 nus. In the period 1968 through 1970 the catch 

 of thread herring in the South Atlantic averaged 

 2,000 metric tons. Thread herring have been 

 considered a potential supplement to the declin- 

 ing menhaden catch on the Atlantic coast, al- 

 though very little is known about population size, 

 distribution, or movement of this species. 



The primary objective of this study was to 

 determine if the thread herring population is 

 large enough and is distributed widely enough 

 to provide an alternate resource for the Atlantic 

 menhaden fishery. In September 1968, we 

 tagged 1,582 thread herring about 1 mile off 

 the North Carolina coast: 299 approximately 2 

 miles west of Beaufort Inlet and 1,283 approx- 

 imately 5 miles east of Bogue Inlet (Figure 1). 



Tags were recovered on magnets at menhaden 

 processing plants during the manufacture of 

 fish meal. Magnets had been installed earlier 

 at all of the plants for recovery of steel tags 

 placed in menhaden. Primary magnets are lo- 

 cated in the plant conveyor system between the 

 fish scrap driers and the scrap storage shed. 

 Almost all tags pass over these magnets the 

 same day fish are processed. Secondary mag- 

 nets were located at other positions in the con- 

 veyor system and may not recover tags until 

 months after the fish are landed when the scrap 

 is ground into meal or is shipped from the plant. 



Test tags were placed in dead fish entering 

 the plant to determine recovery efficiences. Each 



BEAUFORT INLET 

 BOGUE INLET 

 SOUTHPOBT 



Figure 1. — South Atlantic coast of the United States 

 showing areas of tag release and recovery. 



week 100 tags were put into fish at each plant, 

 and recoveries throughout the season from these 

 tests were averaged to determine the plants' re- 

 covery efficiency. 



Recovery Efficiencies 



Average recovery efficiencies were calculated 

 for each recovery area by recovery year. The 

 following formula was used to determine recov- 

 ery efficiency for each test: 



Recovery efficiency = Number of test tags recovered 



Number of test tags released 



Methods and Materials 



The tags and methods currently being used 

 to tag menhaden were applied to thread herring. 



297 



