75 



Abstract— The life history of the At- 

 lantic sharpnose shark {Rhizoprion- 

 odon terraenouae) was described from 

 1093 specimens collected from Virginia 

 to northern Florida between April 

 1997 and March 1999. Longitudinally 

 sectioned vertebral centra were used 

 to age each specimen, and the period- 

 icity of circuli deposition was verified 

 through marginal increment analysis 

 and focus-to-increment frequency dis- 

 tributions. Rhizoprionodon terraenovae 

 reached a maximum size of 828 mm 

 precaudal length (PCD and a maxi- 

 mum age of 11-1- years. Mean back-cal- 

 culated lengths-at-age ranged from 

 445 mm PCL at age one to 785 mm 

 PCL at age ten for females, and 448 

 mm PCL at age one to 747 mm PCL 

 at age nine for males. Observed length- 

 at-age data (estimated to 0.1 year) 

 yielded the following von Bertalanffy 

 parameters estimates: L„= 749 mm 

 PCL (SE=4.60), K = 0.49 (SE=0.020), 

 and tg=-0.94 (SE=0.046) for females; 

 and Z,„ = 745 mm PCL (SE = 5.93), 

 ft:=0.50 (SE=0.024l, and ?o = ^0.91 (SE = 

 0.052) for males. Sexual maturity was 

 reached at age three and 611 mm PCL 

 for females, and age three and 615 mm 

 PCL for males. Rhizoprionodon terrae- 

 novae reproduced annually and had a 

 gestation period of approximately 11 

 months. Litter size ranged from one 

 to eight (mean=3.85l embyros, and in- 

 creased with female PCL. 



Life history of the Atlantic sharpnose shark 

 {Rhizoprionodon terraenovae) (Richardson, 1836) 

 off the southeastern United States 



Joshua K. Loefer 



South Carolina Department of Natural Resources 



Manne Resources Research Institute 



217 Fort Johnson Road 



P,0, Box 12559 



Charleston, South Carolina 29412-2559 



E mail address loefer|(S'mrddnr state scus 



George R. Sedberry 



South Carolina Department of Natural Resources 



Marine Resources Research Institute 



217 Fort Johnson Road 



PO Box 12559 



Charleston, South Carolina 29412-2559 



Manuscript accepted 22 July 2002. 

 Fish. Bull. 101:75-88 (2003). 



The Atlantic sharpnose shark (Rhizo- 

 prionodon terraenovae) is a small 

 carcharhinid that inhabits the coastal 

 waters of the western North Atlantic 

 from the Bay of Fundy to the Yucatan 

 (Castro, 1983). It is the most common 

 small coastal species off the southeast- 

 ern U.S. coast and the Gulf of Mexico 

 ( Branstetter, 1990). This species is 

 frequently encountered by a variety 

 of commercial fishing gear, including 

 bottom longline, gill net, bandit reel 

 (used by the snapper-grouper fishery), 

 and shrimp trawl. Rhizoprionodon ter- 

 raenovae is also a common catch in the 

 recreational hook-and-line fishery. 



The age and growth of this spe- 

 cies has been described in the Gulf of 

 Mexico by Parsons (1981, 1983a, 1985) 

 and Branstetter (1981, 1986, 1987a). 

 Although those studies provided sig- 

 nificant information on the age and 

 growth of R. terraenovae, data were 

 collected from 1979 to 1984, a time in 

 which fishing pressure on the R. terrae- 

 novae population was probably not as 

 high as at present (Cortes, 1995). The 

 previous studies dealt with fishes only 

 from the northern Gulf of Mexico, and 

 therefore may not represent the entire 

 stock, although the stock structure for 

 R. terraenovae in the northwestern 

 Atlantic remains unclear (Heist et al., 

 1996). No published age and growth 

 studies exist for specimens collected 



from the southeastern U.S. Atlantic 

 coast. The reproductive biology of this 

 species has been studied in both the 

 Gulf of Mexico and off the southeast- 

 ern U.S. coast (Parsons, 1983b; Cas- 

 tro, 1988, 1993; Castro and Wourms, 

 1993), but the lack of concurrent age 

 and growth data off the southeastern 

 United States limits the utility of these 

 data for fishery management. 



Considering the importance of accu- 

 rate and timely age, growth, and repro- 

 ductive information to fishery manage- 

 ment, this study had two objectives: to 

 describe age, growth, and reproduction 

 in the southeastern U.S. population of 

 R. terraenovae; and to compare these 

 data to those of previous studies on the 

 same species in the Gulf of Mexico. 



Materials and methods 



Rhizoprionodon terraenovae (/!=1093) 

 were collected throughout the year in 

 coastal waters from April 1997 through 

 March 1999. Collection sites ranged 

 from Chesapeake Bay, Virginia, to 

 Port Canaveral, Florida (Fig. 1). The 

 majority of specimens were collected 

 off the coast of South Carolina. A vari- 

 ety of sampling gears were employed 

 for sample collection: bottom longline 

 (47'7f of specimens), otter trawl (22%), 

 port-sampling of commercial fishing 



