41 



AbStreJCt. -Laboratory experiments 

 were conducted to determine the effects 

 of temperature on egg development and 

 survival of four fish species found off 

 southern California. Our objectives 

 were to further understanding of natu- 

 ral spawning patterns and to aid in 

 identifying and ageing field-collected 

 specimens. An egg-staging procedure 

 was devised and eggs were observed 

 every two hours during development at 

 a range of temperatures <8-28°Cl. 

 Barred sand bass, Paralabrax nebulifer, 

 eggs survived to hatching and produced 

 viable embryos at the highest tempera- 

 ture range (16-28°C), reflecting this 

 species' summer spawning season. Fan- 

 tail sole, Xystreurys liolepis, eggs also 

 hatched at a higher temperature range 

 ( 16-24°C). This species spawns prima- 

 rily from summer through fall. Eggs of 

 the two species with winter-spring 

 spawning peaks, white croaker, Genyo- 

 nemus lineatus, and California halibut, 

 Paralichthys californicus, had lower 

 temperature-tolerance ranges (12- 

 20°C). Developmental rate at a specific 

 temperature did not significantly dif- 

 fer between species, whereas within tol- 

 erance limits, temperature strongly af- 

 fected rate of development for all spe- 

 cies. Time to hatching for all species 

 was inversely related to temperature, 

 and the relationship was approximately 

 exponential. Species-specific differ- 

 ences in egg-stage sequence were ob- 

 served; embryonic organogenesis in re- 

 lation to germ-ring migration and blas- 

 topore closure was faster for barred 

 sand bass and fantail sole than for 

 white croaker and California halibut. 



Effects of temperature on the 

 development and survival of eggs 

 of four coastal California fishes 



Dena M. Gadomski 



VANTUNA Research Group, Occidental College 

 1600 Campus Road. Los Angeles. California 90041 



Present address: Columbia River Research Laboratory 



National Biological Service 



5501 A Cook-Underwood Road. Cook. Washington 98605 



Steven M. Caddell 



Natural History Museum of Los Angeles County, Section of Fishes 

 900 Exposition Boulevard, Los Angeles, California 90007 



Present address: GATX 



2000 E Sepulveda Boulevard. Carson, California 90810 



Manuscript accepted 6 July 1995. 

 Fishery Bulletin 94:41-48 ( 1996). 



Many studies have examined the 

 influence of temperature on the de- 

 velopment and survival offish dur- 

 ing early life history stages (see re- 

 views by Pauly and Pullin, 1988; 

 Pepin, 1991). Since the strength of 

 a year class may be established dur- 

 ing early stages (Hjort, 1914; May, 

 1974 ), it is important to understand 

 possible causes of mortality during 

 this period. For high egg viability, 

 the timing and location of spawn- 

 ing must coincide with favorable 

 environmental conditions including 

 sea temperature (Alderdice and 

 Forrester, 1968; Riley, 1974; Thomp- 

 son and Riley, 1981). Additionally, 

 detailed information on the rela- 

 tionship between temperature and 

 the rate of egg development has 

 been used to age field-collected eggs 

 and to backcalculate spawning time 

 (Ferraro, 1980; Thompson and Riley, 

 1981; Haynes and Ignell, 1983). 



We determined the effects of tem- 

 perature on egg development and 

 survival of four fish species found 

 off southern California: barred sand 

 bass, Paralabrax nebulifer ( Serran- 

 idae); white croaker, Genyonemus 

 lineatus (Sciaenidae); California 

 halibut, Paralichthys californicus 

 (Paralichthyidae); and fantail sole, 

 Xystreurys liolepis (Paralichthyi- 



dae). The first three species are 

 important sport and commercial 

 fishes in this area ( Lavenberg et al., 

 1986). The larvae of these species 

 are relatively abundant in the near- 

 shore zone, where white croaker 

 and California halibut spawn most 

 intensely in winter— spring, and 

 barred sand bass in summer (Love 

 et al., 1984; Lavenberg et al., 1986; 

 Walker et al., 1987; Moser and 

 Watson, 1990; McGowen, 1993). 

 Fantail sole larvae are less common 

 off southern California where peaks 

 in abundance occur during late 

 summer and fall (Moser and Wat- 

 son, 1990). Our primary objective in 

 examining the eggs of these four 

 species was to understand how tem- 

 perature affects development and 

 survival during the critical early life 

 history period and thus contribute to 

 a better understanding of temporal 

 and spatial spawning patterns in the 

 wild. A secondary objective was to 

 gather information to aid in identify- 

 ing and ageing field-collected speci- 

 mens. 



Materials and methods 



Brood stocks of 5-12 adult fish were 

 held in the laboratory in tanks rang- 



