NOTE Ebert and Southon: Confirmation of longevity for Stmngylocentrotus franciscanus with '''carbon 



919 



-130 



130 



0.0 0-5 1.0 1.5 2.0 2,5 0.0 0.5 1.0 1.5 2.0 2.5 



Jaw length (cm) 



Figure 3 



Change in J C %c with successive milled samples from the esophageal end of red sea 

 urchin jaws collected at Halftide Rocks, Washington (48°28.8'N, 1220°59.8'W), 21 Oct. 

 1992. Step width in lines is the width of a milled sample. Jaws of three sea urchins are 

 drawn but a total of 7 were sampled; jaw lengths are A = 2.58 cm, B = 2.54, C = 2.53, 

 D = 2.51, E = 2.29, F = 2.01, G = 1.80 cm; primes represent replicate jaws from the same 

 sea urchin; jaw C is labeled just at the final milled sample (initial sample is just below 

 the initial sample for jaw Al; bands labeled 1 through 4 on jaw G show how samples 

 were milled from the jaw after the surface layer had been removed by approximately 

 0.5 mm. Shaded areas of the jaw, which were not sampled, indicate an area below the 

 top surface where a shelf exists for articulation with the epiphysis, another ossicle of 

 Aristotle's lantern. 



ing elasticity analysis (de Kroon et al., 1986) of a matrix 

 model and have shown that small changes in survival of 

 individuals larger than 9 cm would have a greater effect 

 on population maintenance than survival of smaller sea 

 urchins (Ebert, 1998). The conclusion from matrix analysis, 

 which is supported by the '''C test of growth and age of 

 Strongylocentrotus franciscanus we present in our study, is 

 that the preservation of large individuals must be included 

 in long-term management plans for this species as well 

 as for other long-lived sea urchins in developing fisher- 

 ies such as that for Evechinus chloroticus (Barker, 2001). 

 Finally, our work strongly suggests that life spans of other 

 exploited sea urchm species should be explored in greater 

 detail in developing management plans because preserva- 

 tion of large and old individuals may be very important for 

 the long-term viability of these fisheries. 



Acknowledgments 



Tagging and processing sea urchins were done in collabora- 

 tion with S. Schroeter and J. Dixon, with support from the 

 Pacific States Fishery Commission, a self-imposed landing 

 tax of sea urchin fishermen administered by the Calif 

 Dept. Fish & Game, Oregon Sea Urchin Community Com- 

 mission, and Ore. State Univ. Sea Grant; field work was 

 facilitated by resource managers in California, Oregon, and 

 Washington (P. Kalvass, N. Richmond, A. Bradbury). Stable 

 isotope analysis was done at the University of California 

 at Davis and radiocarbon analysis was funded by a Center 

 for Accelerator Mass Spectrometry minigrant at Lawrence 

 Livermore National Laboratory and was carried out under 

 the auspices of the US DOE. The manuscript benefited 

 from a critical reading by G. Fox. 



