s? 10- 



SITE A 



X = 88 7 1 1 1 5 



n=502 



50 



x = 95.8^8.0 

 n= 306 



UL 



80 90 100 no 

 SHELL LENGTH (mm) 



~~r" 



50 



— r- 



60 



.III 



'O 80 90 100 



SHELL LENGTH (mm) 



li. = 



FISHERY BULLETIN: VOL. 87, NO. 1 



SITE B 



X = 902*98 



n = 509 



Uli 



-1 — ^ 



50 60 70 80 90 100 110 120 



SHELL LENGTH (mn) 



j< = 97.4t 7.5 

 n=l67 



lii_ 



70 80 90 100 110 120 



SHELL LENGTH (mm) 



Figure 3.— Length frequencies of tagged abalone at each site at the beginning (June 1984 - T(,) and at end 



Growth of northern abalone at the transplant and 

 control sites was compared by using the Walford 

 regression to estimate final lengths and associated 

 confidence intervals for abalone of initial lengths 

 equal to the lower (75 mm) and upper (100 mm) size 

 range of abalone placed at the two transplant sites 

 (Table 4). As confidence intervals are narrowest at 

 the mean value of Iq, between site comparisons 

 using these more extreme values are more rigorous 

 than using l^ values which fall between 75 and 100 

 mm. The hypothesis that predicted i, values at Iq = 

 75 and 100 mm for transplanted northern abalone 

 are greater than the corresponding /j value for con- 

 trol abalone was then tested (one tailed ^test). All 

 differences were significant at P < 0.05 (Table 4), 

 indicating that northern abalone growth was 

 significantly greater for abalone transplanted to 

 sites A and B as compared with nontransplanied 

 abalone at the control site. 



Economic Feasibility 



The economic feasibility of transplanting wild 

 northern abalone seed for subsequent commercial 

 harvest depends primarily on three factors: 1) the 

 cost to collect and transplant stock, 2) the rate of 

 recovery of legal-sized abalone after a suitable grow- 



Table 4.— Estimates of growth calculated from Walford plots 

 for abalone for the lower (75 mm) and upper (100 mm) size 

 range of transplanted abalone. Values are expressed + 95% 

 confidence interval. /(, = length at initiation of study, /, = 

 length after nine months. Values in parentheses are / - statistic 

 and degrees of freedom comparing the /, values at each 

 transplant site with the corresponding /, values at the control 

 site. P < 0.05 in all cases. 



Site 



Length after 9 months /, (/,) 



/„ = 100 mm 



A 

 (transplant) 



B 

 (transplant) 



C 

 (control) 



84.7 ± 0.7 

 (16.22, 305) 

 83.3 + 0.9 

 (10.02, 166) 

 78.6 ± 0.4 



102.7 ± 0.5 

 (7.97, 305) 



102.8 ± 0.5 

 (8.85, 166) 



100.5 ± 1.0 



ing period, and 3) the price of abalone. The first fac- 

 tor depends on abalone density in the source area 

 and the distance to the transplant sites. The pres- 

 ent study shows that the second factor (recovery 

 rate) can vary greatly between sites. 



In this study 6 diver-days were required to col- 

 lect 5,000 sublegal-sized northern abalone at the 

 source area and move them to the transplant sites. 

 This variable cost was estimated to be $1,500, at a 

 rate of $250 diver-day ' for wages and fuel costs. 



100 



