478 



Fishery Bulletin 94(3), 1996 



10 15 20 25 30 35 40 45 50 55 



10 15 20 25 30 35 40 45 50 55 

 Midpoint of size class (cm) 



Figure 8 



Length-maturity relationships for male (n=66) and female 

 (n=85) barred sand bass (Paralabrax nebulifer) taken in 

 the southern California Bight, including estimated lengths 

 at which 50% of the bass were mature. Solid line repre- 

 sents predicted relationship. 



ter growth rates. A fish recruited in October may not 

 grow appreciably and, with only length as a crite- 

 rion, would appear to be a new recruit in December. 

 Barred sand bass recruitment in King Harbor was 

 low throughout the 1980s; the large increase in num- 

 bers of older fish was probably due to immigration 

 from outside the harbor. 



We believe that the increase in abundance of kelp 

 bass and barred sand bass in King Harbor during 

 the late 1970s and 1980's may be related to a gen- 

 eral warming trend of southern California waters 

 during the period (Stephens et al., 1994). A signifi- 

 cant increase in catches of both kelp and barred sand 

 bass occurred then throughout the southern Califor- 

 nia Bight (Love et al. 2 ). In fact, the increase in bass 

 populations may have been part of a general alter- 

 ation of nearshore fish populations, resulting from 

 warming ocean waters. During this period, colder- 

 water species (such as rockfishes) declined in abun- 

 dance, whereas populations of warm-temperate and 

 subtropical species (including labrids and poma- 

 centrids) increased (Stephens et al., 1986). This trend 



has also been noted among nearshore pelagic spe- 

 cies, such as chub mackerel (Scomber japonicus) and 

 Pacific sardine (Sardinops sagax) (Barnes et al., 

 1992). 



Age and growth 



Although no other study of barred sand bass growth 

 rates is available, some age-length data derived from 

 scales, for kelp bass, have been reported in Young 

 (1963). We compared our age-at-length estimates 

 (from the von Bertalanffy equation) with the mean 

 length at age calculated by Young (Table 3). Except 

 for the very youngest and the very oldest fish, our 

 data sets are similar, particularly at ages 4-7. 



The results of our comparison of growth rates of the 

 two species suggest that there is little difference be- 

 tween kelp bass and barred sand bass. We were un- 

 able to reject our "combined species" model by fitting 

 the age and length data for both species to one growth 

 curve in favor of our "separate" model which fits the 

 three growth parameters separately for each species. 



