Love et al Life history aspects of Paralabrax clathratus and P nebulifer 



479 



Since individuals of both species appear to be ad- 

 equately described by a common age-length relation- 

 ship, a comparison of size records for each species 

 may provide some insight into their relative 

 longevities. Eschmeyer et al. (1983) reported maxi- 

 mum lengths of 72 cm and 65 cm for kelp bass and 

 barred sand bass, respectively. These lengths suggest 

 that kelp bass may be the longer lived of the two spe- 

 cies. Indeed, the oldest kelp bass we found was 33 yr (a 

 new record), the oldest barred sand bass was 24 yr. 



Length and age at first maturity 



Clark ( 1933) reported on length at first maturity for 

 kelp bass and barred sand bass taken in the com- 

 mercial catch and landed at San Pedro. In that study, 

 all kelp bass <25 cm were immature (note that she 

 used fork length [FL]), and she assumed that the 

 "average size at first maturity" was about 26 cm FL. 

 We also found that there was little difference in 



Table 2 



Maximum-likelihood estimates for the parameters of the lo- 

 gistic equation relating proportion mature to lengths and ages 

 of kelp bass (Paralabrax clathratus) and barred sand bass (P. 

 nebulifer). Predictive length W 050 ) and age (a £ e o50* at ^0^ 



Males 

 Females 



-5.67 

 -4.11 



13.81 

 11.91 



2.0 

 3.0 



0.94 

 0.91 



length at first maturity for the two species. However, 

 if we take "average size at first maturity" to mean 

 length at which 50% of the individuals are mature, 



