Tagging and Tag-Recovery Experiments With 

 Atlantic Menhaden, Brevoorf/a tyronnus 



By 



RICHARD L. KROGER 1 and ROBERT L. DRYFOOS 2 



ABSTRACT 



Laboratory tagging experiments with adult and juvenile Atlantic menhaden were 

 conducted at Beaufort, N.C., in 1965 and 1969. Tag-recovery experiments were done at 

 menhaden processing plants at Beaufort, N.C. Internal ferromagnetic body tags of appro- 

 priate sizes are suitable for tagging adults and juveniles, and the tags can be recovered 

 effectively on magnets in the processing plants. 



INTRODUCTION 



Information on the movements, mortality, 

 and recruitment of Atlantic menhaden are avail- 

 able from catch, effort, and length-frequency 

 data; but more direct, independent estimates 

 of these parameters, derived from mark-recap- 

 ture studies, are desirable. We conducted a se- 

 ries of laboratory experiments in 1965 to deter- 

 mine the best techniques for tagging and han- 

 dling adult menhaden. These experiments were 

 designed to estimate the amount of tag shed- 

 ding and fish mortality that could be expected 

 for fish exposed to different techniques of tag- 

 ging and handling. Our tag-recovery experi- 

 ments were designed to estimate the recovery 

 rates for tags which entered each menhaden 

 reduction plant. In 1969 we conducted similar 

 experiments with juvenile menhaden using 

 smaller tags. This paper reports the methods 

 we used and the conclusions we reached and 

 includes a brief review of former tagging exper- 

 iments. 



i National Marine Fisheries Service, Atlantic Estu- 

 arine Fisheries Center, Beaufort, N.C. 28516. 



2 National Marine Fisheries Service, Northeast 

 Fisheries Center, Narragansett Laboratory, Narragan- 

 sett, Pv.I. 02882. 



REVIEW OF MENHADEN 

 TAGGING 



Since menhaden are mass-processed into meal, 

 oil, and solubles, the fish must be marked with 

 tags that can be recovered mechanically or elec- 

 tronically from the reduction plants. Internal 

 metallic tags were experimented with initially 

 since they had been found satisfactory to mark 

 clupeids by other workers (Rounsefell and Dahl- 

 gren, 1933; Dahlgren, 1936; California Division 

 of Fish and Game, 1945; Fridriksson and Aasen, 

 1950; Bayliff and Klima, 1962; and Newman, 

 1970). 



The results from the first attempt, in 1959, 

 to mark juvenile menhaden with internal ferro- 

 magnetic tags were unsuccessful (Reintjes, 

 1963). This tag, a nickel-plated iron toroid, 19.0 

 by 4.0 by 1.5 mm, with rough edges, caused 

 internal damage to the small menhaden. 



A photoelectric device to detect fish marked 

 with biological stains and dyes was designed, 

 constructed, and tested during 1959-62 (Reintjes, 

 1963). He reported that the naturally occurring 

 fluorescence in menhaden and other marine or- 

 ganisms made discrimination of marked men- 

 haden impractical without modification of the 

 photoelectric device. 



