Chiang et al.: Analysis of sex-specific spawning biomass per recruit of Istiophorus platypterus in off eastern Taiwan 
271 
A 
2 B 
Figure 5 
Yield per recruit ( Y/R ) against fishing mortality per year for 
female (A) and male (B) sailfish (Istiophorus platypterus) in the 
waters off eastern Taiwan. • = F c UR and O = F 01 . 
Table 5 
Estimates of current fishing mortality (E CUR ) and the reference points of SSB/R SSBx and SPR at different levels of natural mor- 
tality ( M ) for female sailfish (Istiophorus platypterus) in the waters off eastern Taiwan during the period from July 1998 to July 
2005. F SSBx = the fishing mortality rate corresponding to SSB /R SSBx ; SSB/R SSBx = a specific percentage ( x% ) of the spawning 
biomass per recruit at the unfished level; SPR (spawning potential ratio) = the SSB/R at a given fishing mortality divided by the 
SSB/R without fishing. 
M 
(1/yr) 
^CUR 
(1/yr) 
^SSB40 
(1/yr) 
^SSB25 
(1/yr) 
SSB/R cur 
(kg) 
SSB/R ggB40 
(kg) 
SSB/R ggB25 
(kg) 
SPRcur 
(%) 
0.20 
0.26 
0.36 
0.67 
32.50 
26.56 
16.60 
48.96 
0.26 
0.24 
0.46 
0.94 
22.22 
15.53 
9.71 
57.20 
0.30 
0.22 
0.54 
1.22 
17.42 
11.14 
6.96 
62.57 
0.35 
0.20 
0.70 
1.73 
12.97 
7.52 
4.70 
68.95 
the changes in F but were very sensitive to the uncer- 
tainty in M. Adding the uncertainty in t c resulted in 
slightly higher estimates of F 0 1 than that for the base 
case. Higher estimates of F 0 1 could have resulted from 
t c with values larger than 5 years (base case) selected 
in this scenario. In the case of this study, higher t c pro- 
