FISHERY BULLETIN: VOL. 81. NO. 1 



man and Springer 1950). Bigelow and Schroeder 

 (1948) reported that specimens from Texas 

 showing traces of the umbilical scar were from 

 280 to 407 mm long. 



Among R. terraenovae populations, adults are 

 commonly 26 to 30 in (66 to 76 cm) total length 

 (TL) (Baughman and Springer 1950), but the 

 size at which male and female Atlantic sharp- 

 nose sharks mature is unknown. In his revision of 

 the genera Scoliodon, Loxodon, and Rhizoprion- 

 odon, V. G. Springer (1964) reported that insuffi- 

 cient information was available to establish the 

 size at which males first mature but it appeared 

 that maturation occurs at >640 mm TL. Bass et 

 al. (1975) reported that male R. acutus mature 

 between 68 and 72 cm and females at 70 to 80 cm 

 TL. 



The present study is an attempt to clarify some 

 of the known aspects of R. terraenovae reproduc- 

 tive biology as well as to provide additional in- 

 formation. The reproductive "strategy" of the 

 Atlantic sharpnose shark is also examined. 



METHODS AND MATERIALS 



Atlantic sharpnose sharks, Rhizoprionodon 

 terraenovae (Richardson), were collected in the 

 north central Gulf of Mexico from June 1979 to 

 May 1980. The principal sampling devices em- 

 ployed were longline, trawl, and rod and reel. 



Floating longline generally gave the best re- 

 sults (Table 1). The technique, as used by Japa- 

 nese fishermen, is described by Lopez et al. 

 (1979). Because of the hazard to navigation that a 

 floating longline represents, longlining opera- 

 tions were undertaken exclusively in deep waters 

 offshore (Fig. 1). Longline sets were made in 10 

 to 28 fathom (18 to 51 m) depths, approximately 

 due south of Dauphin Island, Ala. A trawl was 

 used to collect specimens both inshore as well as 

 offshore. Rod and reel, gill net, and seine were 

 used exclusively inshore. 



Specimens were immediately weighed and 

 sexed. Total, fork, and standard lengths were 



30 u 

 30' 



30" 



15' 



30 u 



00' 



29 u 

 »5' 



29 u 

 30' 



MOBILE 



O. 

 O 



0^2) 

 DAUPHIN q 

 ISLAND 



fort Morgan' 

 o 



••-S 



GULF OF MEXICO 



10 fm 



20 fm 



30 fm 



15' 



00' 



87° k5' 



Figure 1.— Coastal Alabama study area of the Atlantic sharp- 

 nose shark. Offshore points (closed circles) represent longline 

 and trawl sites. Inshore points (open circles) represent trawl, 

 gill net, rod and reel, and seine sites. 



measured to the nearest 0.1 cm. Lengths of the 

 claspers and siphon sacs were measured on all 

 male specimens. All specimens were dissected 

 immediately in the field by an incision starting 

 at the cloaca and extending to the midpectoral 

 region. Notes on reproductive condition in males 



Table 1. — Landings of Atlantic sharpnose sharks by month and by method. Longline and trawl produced more than 60% of the 

 sharpnose shark specimens. Sharpnose sharks were collected in 10 of the 12 mo of the study period. — indicates no collections; 

 indicates collections attempted but no sharks landed. 



62 



