944 



Abstract.— Growth parameter esti- 

 mates were calculated for the tiger 

 shark (Galeocerdo cuvier) by using tag 

 and recapture data. Results were com- 

 pared to published estimates based on 

 bands in vertebrae. The von Bertalanffy 

 parameters (sexes combined) based on 

 tag and recapture growth data were as 

 follows; L„ = 337 cm fork length, k - 

 0.178, and /o= -1.12. Monthly length- 

 frequcmcy data for six year classes from 

 birth to two years old for tiger sharks 

 were used to verify the tag-recapture 

 growth curve for this age range. The 

 predicted age at maturity is 7 years for 

 both sexes. Data from an ongoing in situ 

 study with oxytetracycline were used 

 in conjunction with length data to de- 

 termine the effect of tagging and oxytet- 

 racycline injection on growth. The data 

 suggest that tagging alone or tagging 

 combined with oxytetracycline injection 

 has little or no effect on the growth rate 

 of tiger sharks up to two years of age. 



Growth of the tiger shark, Galeocerdo cuvier, 

 in the western North Atlantic based on 

 tag returns and length frequencies; 

 and a note on the effects of tagging 



Lisa J. Natanson 

 John G. Casey 

 Nancy E. Kohler 



Narragansett Laboratory 



Northeast Fisheries Science Center 



National Marine Fisheries Service, NOAA 



Narragansett, Rhode Island 02882-1199 



E-mail address (for L J Natanson) LnatansoawhsunI wh whoi edu 



Tristram Colket IV 



2020 Cordova Ave 



Vero Beach, Florida 32960 



Manuscript accepted 29 September 1998. 

 Fish. Bull. 97:944-953 (1999). 



Adult tiger sharks, Galeocerdo 

 cuvier, occur worldwide in temper- 

 ate and tropical coastal waters. In 

 the North Atlantic, they reside year 

 round off the coast of Florida and 

 seasonally migrate north as far as 

 Nova Scotia, Canada (Kohler et al., 

 1995), Additionally, tiger sharks are 

 known to make extensive migra- 

 tions throughout the North Atlan- 

 tic, on occasion traveling to Cuba 

 and Africa,' The tiger shark is 

 listed under the large coastal shark 

 category of the Fisheries Manage- 

 ment Plan for Sharks of the Atlan- 

 tic Ocean (Anonymous, 1993), Al- 

 though it is not a target species of 

 the U,S, inshore longline fishery, 

 small tiger sharks are frequently 

 caught and released alive. Tagging 

 and fishery data indicate that there 

 is a nursery ground for tiger sharks 

 on the continental shelf off the 

 southeast coast of the US,' This 

 area extends from about Augusta, 

 GA, to Daytona, FL, and extends 

 from shore seaward to depths of 

 100 m, A similar area exists off the 

 coast of North Carolina,- In these 

 areas, tiger sharks of birth size 

 ranging from 61 cm fork length 

 (FL)) to 120 cm FL are commonly 



caught in the commercial longline 

 fishery. In the Northwest Atlantic, 

 tiger sharks mature between 258 

 and 265 cm FL (Branstetter et al., 

 1987) and have been reported to 

 attain a size of 469 cm FL (Castro, 

 1983), 



Branstetter et al, ( 1987) used the 

 alternating opaque and translucent 

 bands formed in the vertebral cen- 

 tra to age tiger sharks caught in the 

 western North Atlantic and the Gulf 

 of Mexico, Attempts to verify these 

 estimates with length-frequency 

 analysis proved unsuccessful owing 

 to the inability to distinguish age 

 groups, Branstetter et al, (1987) 

 tried to corroborate the vertebrally 

 derived growth rate with results 

 from one tag-recapture individual; 

 however, this individual's length 

 was estimated at both tagging and 

 recapture. Owing to the high age 

 estimates at L„, Branstetter et al. 

 (1987) suggested that as tiger 



' 1992-98. Apex Predators Program, 28 



Tarzwell Dr. Narragansett, RI 02882. 



NMFS unpub. data. 

 ~ Chris Jensen. 1994. Natl. Mar. Fish. 



Serv, NOAA, 28 Tarzwell Dr, Narragansett, 



Rl 02882. Personal Commun. 



