Moser and Pommeranz Distribution of eggs and larvae of Engraulis mordax 



941 



below the peak depth zone of anchovy larval abun- 

 dance before the storm, whereas it coincided with 

 the depth zone of highest larval abundance after- 

 wards. Pre- and poststorm peak concentrations of 

 important fish larva prey coincided with pre- and 

 poststorm peaks in the chlorophyll maximum (MuUin 

 et al., 1985). If starvation was the reason for the de- 

 cline in anchovy larvae, then it is likely that the cause 

 was disruption of micropatches of food, as suggested 

 by Mullin et al. (1985). In this case, Lasker's (1981) 

 stable ocean hypothesis was operative at the centi- 

 meter scale, and reduced survival was a result of dis- 

 ruption of the fine-scale geometry of food patches 

 (Vlymen, 1977; Owen, 1989).Another explanation for 

 the poststorm decline in anchovy larval abundance 

 would be advection of larvae away from the study 

 site (Mullin etal., 1985). The strong northwest winds 

 resulted in offshore movement of surface water (the 

 upper 10 m) by Ekman transport at a rate of about 

 10 cm per second; thus, virtually all the surface wa- 

 ter at this region of the shelf was moved offshore 

 during the storm and was replaced by deeper water 

 (WinantM. This could explain the sharp decline in 

 anchovy larval densities at the slope station after 

 the storm, providing, of course, that densities of an- 

 chovy larvae were lower over the shelf than at the 

 station before the storm. The latter would not be 

 expected since Barnett et al. ( 1984 ) showed high con- 

 centrations of anchovy larvae over the shelf at a simi- 

 lar habitat south of our inshore station. 



The storm had an opposite effect on densities of 

 shorefish larvae (Genyonemus lineatus, Seriphus 

 politus, Pepriliis simillimiis, Paralichthys califor- 

 nicus, Citharichthys spp.), which occurred in ex- 

 tremely low densities or which were absent in 

 prestorm samples. Larval densities of these species 

 began to increase immediately after the storm, 

 peaked within 1-2 days, and then declined abruptly 

 to prestorm levels. The sudden appearance of these 

 larvae at the nearshore station after the storm was 

 a result of storm-induced advection from shallow 

 regions of the shelf The narrow shelf in this region 

 of the coast would make nearshore fish lai"vae par- 

 ticularly vulnerable to transport off the shelf during 

 storms with northwest winds. Such advection may 

 be important in the transport of nearshore fish lar- 

 vae seaward where they become available to slope 

 or eddy circulation, thus providing the opportunity 

 for dispersion to other regions. The subsequent rapid 

 decline in larval densities could have been caused 

 by mortality associated with disturbance of micro- 



ti C. D.Winant. 1998. Center for Coastal Studies, Scripps In- 

 stitution of Oceanography, La JoUa, CA 92093. Personal 

 commun. 



patches of food, by predation, or by active or passive 

 movement of larvae away from the sampling site. 

 Starvation of these inshore larvae over slope waters 

 may be related to the difference in composition and 

 concentration of prey organisms in nearshore and 

 offshore waters (Watson and Davis, 1989). Some por- 

 tion of the larvae that appeared at the inshore site 

 after the storm may have been transported back to 

 the nearshore region. This return transport may have 

 been enhanced by upward movement of these larvae 

 to the surface where they could be carried by shore- 

 ward currents created by internal wave cells (Shanks, 

 1983, 1986). 



Among the species with deeper-living larvae, those 

 of Sebastes spp. declined markedly in all strata after 

 the storm, whereas those of Stenobrachiiis leucop- 

 sarus showed a decline in deeper strata but increased 

 in strata shallower than 30 m. This probably was 

 caused by upward turbulent advection of larvae from 

 deeper strata. Likewise, larval density of Leuro- 

 glossus stilbius increased in strata shallower than 

 50 m following the storm, with sporadic high counts 

 in individual tows, suggesting pulses of upwardly 

 advected larvae. 



Acknowledgments 



We are indebted to the members of the scientific party 

 of Cruise 8003-EB (Jack Brown, John Butler, Carol 

 Kimbrell, Barbara Sumida-McCall, Elaine Sandknop 

 Acuha, and Elizabeth Stevens) for their outstanding 

 work in all phases of cruise operations. The efforts 

 of Captain L. E. Davis and the crew members of the 

 RV Ellen B. Sc/'ipps were crucial to the completion 

 of the cruise objectives. The late J. T Thrailkill su- 

 pervised sorting of the plankton and processing of 

 the fish eggs and larvae. Barbara Sumida-McCall, 

 Elaine Sandknop Acuiia, and Elizabeth Stevens 

 staged the anchovy eggs and identified and measured 

 fish larvae. We are indebted to Carol Kimbrell for 

 directing the chlorophyll sampling at sea and to Rob- 

 ert Owen for his help in working up the chlorophyll 

 data from these samples. Richard Charter assisted 

 us in all aspects of data processing associated with 

 this study. William Watson checked identifications 

 of some nearshore fish families and offered sugges- 

 tions that improved the manuscript. We thank 

 Michael Mullin for reading the manuscript and for 

 his comments and suggestions. Discussions with 

 Clinton Winant were helpful in understanding 

 nearshore circulation and transport. We are grate- 

 ful to Nancy Lo for her review of the manuscript and 

 for statistical procedures. The comments and sug- 

 gestions of three anonymous reviewers greatly im- 



