NOTE Hazin et a\: Reproduction of Carchannus aaonotus 



147 



arv>, mating and fertilization during April and 

 May (autumn ) would result in a gestation peri- 

 od of approximately 8 months — slightly short- 

 er than that suggested by Schwartz ( 1984) and 

 Dodrill 1 1977) (9 and 10 to 11 months, respec- 

 tively) for stocks off the southeastern United 

 States. Further, the periods required for vi- 

 tellogenisis and gestation indicate that repro- 

 duction of C acronotiis off northeastern Brazil 

 could be completed within 10 to 11 months. 



With the simultaneous capture of nongravid 

 and gi-avid females off Florida, Dodrill (1977) 

 proposed a biennial reproductive cycle for C. ac- 

 ronotus. Although we also collected gravid and 

 nongi-avid (i.e. postpartum and resting) females 

 together (i.e. mostly during December and Jan- 

 uary), the latter individuals could have given 

 birth 3 or 4 weeks earlier If these females sub- 

 sequently ovulated 2 months later (in April), 

 then reproduction could conceivably be annu- 

 al. A fast vitellogenic period, combined with 

 clear reproductive progress, is also supportive 

 of a 1-year cycle. An alternative hypothesis that 

 supports biennial reproduction is that the rest- 

 ing females represented some proportion of seg- 

 regated nongravid females that moved with the 

 relatively large numbers of gravid females into 

 the parturition area. Given the lack of adult fe- 

 males in catches between June and November (winter to 

 late spring), it is likely, however, that they frequent other 

 areas after copulation. Without additional fishery-indepen- 

 dent data, it is impossible to determine these locations and 

 whether some proportion of the female population consists 

 of nongravid or resting individuals throughout the yean 



Our evidence suggests a shorter reproductive cycle for 

 C. acronotus than that previously noted in the literature. 

 Given the 6-month difference between times of ovulation 

 and parturition for females off northeastern Brazil and 

 those off the southeastern United States, our results also 

 indicate the existence of at least two separate stocks. Not- 

 ing temporal differences in the sizes of embryos from fe- 

 males, Schwartz (1984) proposed two partially separated 

 populations off the southeastern United States: one off 

 North Carolina and the other comprising individuals from 

 Florida and the Gulf of Mexico. Additional research is 

 needed to determine if the population in the southwest- 

 ern Atlantic is separate from those in the north because 

 the existence of a unit stock off northeastern Brazil would 

 require separate management measures according to the 

 status of that stock. 



Acknowledgments 



This study was funded by the Comissao Interministerial 

 para os Recursos do Mar (CIRM) through the Programa 

 Nacional de Avalia^ao dos Recursos Vivos da Zona 

 Economica Exclusiva ( RE VIZEE ), the Fundagao de Amparo 

 a Ciencia e Tecnologia do Estado de Pemambuco ( FACEPE ), 

 and the Conselho Nacional de Ensino e Pesquisa (CNPq). 



We thank T. Souza, H. Requiao, P. Pinheiro, and L. Wojciuk 

 for technical assistance and R. Lessa for critically reading 

 the manuscript. 



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