TEGNER ET AL : BIOLOGY AND MANAGEMENT OF RED ABALONES 



c 



D 



180 

 172 

 164 



155 



148 



140 



132 



124 



1160 



108 



100 

 I 

 180 



172 



164 



156 

 148 

 140 



FISHING MORTALITY RATE 



Figure 8.— Continued— anfished cohort. See text for procedure. Parameters were all identical with 

 those used in Figure 6. 



1,008) commercial minimum legal-sized animals. The 

 density of red abalones at Johnsons Lee is compar- 

 able to the average 0.2 abalones per m- found in 

 the Victorian fishery for H. rubra (Beinssen 1979a) 

 but considerably less than recent mean densities 

 of H. kamtschatkana in British Columbia (Breen 

 1986). 



Bar cuts have been a continuing problem in 

 California abalone fisheries. Burge et al. (1975) 

 reported market sampling data from 1974, indi- 

 cating that commercial divers cut 8.6% of their red 

 abalone catch. They felt that the bar cut rate of 

 picked and replaced sublegal animals was likely to 

 be higher because of their more cryptic nature. 

 These authors found a nearly 60% mortality rate in 

 laboratory studies of//, rufescens with a 13 mm cut 

 in the foot; mortality is likely to approach 100% in 



the presence of predators. They presented size- 

 frequency data for pink, H. corritgata, and green, 

 H. fulgens, abalones which showed decreases in the 

 number of animals within 6 mm of commercial mini- 

 mum legal size. While the decreases could have been 

 caused by sport harvest or commercial take of sub- 

 legal animals, Burge et al. (1975) believed that they 

 were caused largely by the mortality of picked and 

 replaced short abalone. Figures 3A and 4 illustrate 

 similar marked drops in the number of red abalones 

 within 5 mm of both sport and commercial minimum 

 legal size. The size-frequency distributions of shells 

 (Fig. 5) provide strong evidence for mortality of 

 picked and replaced short abalones by sport and 

 especially commercial fishermen. The approximately 

 10% of total observed mortality which we have at- 

 tributed to bar cuts is especially damaging to fish- 



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