FISHERY BULLETIN: VOL. 82, NO. 1 



500 



400 



< 



I 300 



m 



3 

 Z 



200 



100 



FIGURE 18.— Lengths of white croaker retained by com- 

 mercial gill net fishermen off southern California, 1980- 

 81. 



100% 



18 20 22 24 26 28 



TOTAL LENGTH (cml 



30 



32 



34 



depths of perhaps 9 m (Skogsberg 1939), whereas 

 Cheilotrema saturnum are common over reefs to 

 perhaps 15 m (occasionally to 45 m) (Limbaugh 

 1961). 



Most eastern Pacific drums are limited to the warmer 

 waters south of Point Conception (Miller and Lea 

 1972) or, like the queenfish and white seabass, are 

 rare north of the Point. Conversely, white croaker are 

 abundant north to San Francisco. Temperature pre- 

 ference experiments 12 indicate that juvenile white 

 croaker have wide metabolic thermal optima (11°- 

 17 C, based on routine oxygen consumption rates) 

 that may account for their wide depth and 

 latitudinal ranges. 



Though white croaker are most abundant over sandy, 

 featureless substrata, they are occasionally found in 

 large numbers in kelp beds. This is particularly the 

 case in beds anchored on sand, such as those off San 

 Onofre and Santa Barbara. Similarly, though they 

 spend most of their time near the bottom, we have 

 noted schools in midwater, 20-40 m or more above 

 the substrata. We have also seen white croaker at the 

 surface, chasing anchovy schools. 



Maturation and Reproduction 



We computed the length-maturity relationship 

 using standard length to compare our results with 



1! Hose, J. E., and W.H.Hunt. 1981. Physiological responses of 

 juvenile marine fish to temperature. Occidental College Annual 

 Report submitted to Southern California Edison, 17 p. 



those of Issacson (1967). We found 50% of the males 

 mature by 12.0 cm SL and 50% of females by 13.0 cm 

 SL, both at 1 yr. This was in sharp contrast to Issac- 

 son's statement that "The white croaker matures 

 between 147 and 164 mm standard length at an age of 

 3 to 4 years." Why such a disparity should exist is 

 unclear. 



White croaker is the only southern California drum 

 that spawns in the winter. Winter spawning is 

 unusual even among tropically derived temperate 

 species off California. All species in the families 

 Blenniidae, Carangidae, Labridae, Pomacentridae, 

 Scombridae, and Sphyraenidae are either summer 

 spawners or spring and summer spawners with a 

 summer spawning peak. An exception are the rock- 

 fishes (Scorpaenidae), the vast majority of which 

 spawn in winter and/or spring. 



The more or less continuous (or perhaps dual- 

 peaked) spawning season seen in white croaker in 

 Monterey Bay is an interesting phenomenon. Most 

 California marine fishes have restricted spawning 

 seasons. If spawning does continue for extended 

 periods (as in the bocaccio, Sebastes paucispinis), 

 there is usually only one peak spawning period. An 

 exception is the northern anchovy, Engraulis mor- 

 dax, that may spawn year-round and which exhibits a 

 major peak in late winter-early spring and a minor 

 one in early fall. 



Fishes of the northeastern Pacific tend to have a 

 longer spawning season in the southern part of their 

 range, as favorable conditions are usually more re- 



194 



