422 



Fishery Bulletin 105(3) 



breeders were not significantly (P=0.42) different from 

 each other and were thus combined to produce a single 

 equation to describe the likelihood of producing one or 

 two broods of eggs: 



POoA= exp[-0.3lx]n{DA + l) + 0J42]-l. 



The above relationship between appendage damage and 

 the likelihood of lobsters developing ovigerous setae, or 

 the likelihood of lobsters producing one or two broods 



£. 40 



A New appendages 



B E 



30 



- S 20 - 



10 



Females. n=25,218 

 Males, n=1 6,482 



60-69 



70-79 



80-89 



90-99 100-109 110-119 120-129 



Females, n=25,218 

 Males, n=1 6,482 



of eggs at the Abrolhos Islands, was very similar in the 

 other two coastal management zones. 



The influence of appendage damage on fecundity 



The mean fecundity per spawning season of female 

 P. cygnus with a standardized CL of 77.0 mm did not 

 differ significantly (P>0.05) between females with and 

 without damaged appendages (i.e., 249,885 ±7873 eggs 

 and 234,164 ±7094 eggs, respectively). Furthermore, 

 regressions between fecundity (F) and 

 carapace length (CL) of female P. cygnus 

 with and without damaged appendages 

 (Fig. 5) did not differ from each other 

 (P>0.05 ) and were both very similar to the 

 relation of carapace length to fecundity 

 recorded for this species by Chubb (1991). 

 The effect of damaged appendages on 

 the number of eggs produced per spawn- 

 ing season by female P. cygnus at the 

 Abrolhos Islands was greater for large 

 than for small females (Fig. 6). For 

 example, two damaged appendages re- 

 duced the fecundity of a 70-mm-CL lob- 

 ster by about 114,000 eggs, whereas the 

 fecundity of a 120-mm-CL lobster was 

 reduced by about 1,000,000 eggs (Fig. 6). 

 The total number of eggs produced 

 in the 2002 survey was estimated for 

 each of the three management zones 

 separately for females with and with- 

 out appendage damage. The inclusion 

 of appendage damage significantly (all 

 P<0.001, paired <-test) reduced egg pro- 

 duction estimates by 8.5%, 3%, and 9% 

 in zones A, B, and C, respectively. 



60-69 



70-79 



80-89 



90-99 



100-109 110-119 120-129 



£ « 20 



> i 



CO CT 



O CO 



r ^10 



O Q. 

 CO 0) -> 



C Regenerated appendages 



Females, f?=25,218 

 Males, n=1 6,482 



60-69 70-79 80-89 90-99 100-109 110-119 120-129 



Carapace length (mm) 



Figure 3 



Percentage of female and male western rock lobster ^Panulirus cygnus) 

 in different size classes with (A) new or (B) old appendage loss, or (C) 

 with regenerated appendages. The analysis uses 2001-0.5 fishery-inde- 

 pendent breeding stock survey data from all five coastal sites. 



Discussion 



The incidence of appendage damage 



The proportions of lobsters with damaged 

 appendages varied markedly between 

 sexes, sizes, and locations sampled. How- 

 ever, the timing and frequency within 

 a year that molting takes place for the 

 sexes, and for different-size animals, 

 plays only a relatively minor role in influ- 

 encing these differences. Female west- 

 ern rock lobsters generally molt twice 

 a year; February-March and again in 

 May. A significant proportion of large 

 breeding females occasionally skip the 

 February-March molt, but all take part 

 in the May molt (de Lestang and Mel- 

 ville-Smith, 2006). 



New appendage damage occurred 

 around the time of capture and could 

 mostly be attributed to the survey sam- 



