Larval Fish Diets in Shallow Coastal Waters off San Onofre, 



California 



William Watson and Raymond L. Davis, Jr. 



ABSTRACT: Stomach contents were analyzed 

 from the larvae of six common coastal fish taxa 

 (Atherinopsis californiensis, Leuresthes tenuis, 

 Paralabrax spp., Genyonemus lineatus, Seriphus 

 politus, and Paralichthys californicus) collected 

 near San Onofre, California. Samples were col- 

 lected at night at approximately monthly inter>als 

 between September 1978 and September 1979 dur- 

 ing a study of ichthyoplankton distributions in 

 these shallow coastal waters. 



Paralabrax spp. and Paralichthys californicus 

 larvae apparently did not feed at night, but high 

 feeding incidences for the atherinids and especially 

 the sciaenids suggested that these lar\ae did feed 

 during early evening hours. Important components 

 of the diets of all six taxa included the tintinnid 

 genus Stenosomella, mollusc veligers, and espe- 

 cially the copepod Euterpina acutifrons. 



The vertical distributions of the fish lanae dif- 

 fered from the reported distributions of some of 

 their principal prey taxa, suggesting that factors in 

 addition to, or other than, specific feeding habits 

 are important determinants in the nearshore distri- 

 butions of fish lanae. The avoidance of seaward 

 dispersal away from the relatively productive and 

 stable nearshore zone may be an important factor 

 influencing larval distribution. 



Most studies on the feeding habits of fish larvae 

 in the Southern California Bight have focused on 

 species whose larvae occur primarily beyond the 

 continental shelf, or are broadly distributed 

 across the shelf and beyond (Arthur 1956, 1976; 

 Hunter and Kimbrell 1980; Lasker 1975; Sumida 

 and Moser 1980, 1984; Theilacker 1986). Larval 

 fish feeding in the shallow coastal zone (depth 

 <75 m) has, until recently, received relatively 

 little attention. Lasker (1975, 1981) examined 

 the requisite conditions for the successful first 



William Watson, MEC Analytical Systems, Inc., 2433 

 Impala Drive, Carlsbad. CA 92009; present address: South- 

 west Fisheries Center LaJoUa LaboratoiT, National Marine 

 Fisheries Service. NOAA. P.O. Box 271, LaJolla, CA 92038. 

 Raymond L. Davis, Jr., MEC Analytical Systems. Inc., 

 2433 Impala Drive, Carlsbad, CA 92009; present address: 

 Sea World, Aquarium Department, 1720 South Shores 

 Drive, San Diego, CA 92109. 



Manuscript accepted May 1989. 

 Fishery Bulletin, U.S. 87: 569-591. 



feeding of larval northern anchovy and sug- 

 gested that the shallow nearshore zone may pro- 

 vide a better larval feeding environment than 

 offshore waters, largely because of the more 

 stable nature of the nearshore zone. 



It has become increasingly apparent in recent 

 years that this shallow nearshore zone is a 

 unique area supporting distinctive, stable as- 

 semblages of fish larvae and zooplankters 

 (Brewer et al. 1981, 1984; Graber et al. 1982; 

 Barnett et al. 1984; Brewer and Kleppel 1986; 

 Petersen et al. 1986; Barnett and Jahn 1987; 

 Walker et al. 1987). Feeding studies are begin- 

 ning to be reported for some of the fish larvae 

 that are largely restricted to this zone (Brewer 

 and Kleppel 19*86; Jahn et al. 1988). 



The purpose of this report is to document the 

 food habits of the larvae of six fish taxa in the 

 shallow coastal waters off southern Cahfornia. 

 These six taxa include larvae occupying all levels 

 of the water column: larval jacksmelt, Ather- 

 inopsis califoniiensis, and gi-union, Leuresthes 

 temds, are largely restricted to the neuston and 

 upper water column; California halibut, Para- 

 lichthys californicus, and kelp and sand bass, 

 Paralabrax spp., larvae occur throughout the 

 water column but tend to be most abundant in 

 midwater; and larval queenfish, Seriphus pol- 

 itus, and white croaker, Genyoneinus lineatus, 

 occur principally in the lower water column and 

 epibenthos (Schlotterbeck and Connally 1982; 

 Barnett et al. 1984; Jahn and Lavenberg 1986). 

 All six taxa occur principally near shore through- 

 out life (Frey 1971; Miller and Lea 1972; Barnett 

 et al. 1984; Lavenberg et al. 1986;). 



METHODS 



Plankton samples were collected between 25 

 July 1978 and 23 September 1979 near San 

 Onofre, CA (lat. 33°20'N, long. 117°30'W). The 

 plankton sampling methodology and rationale 

 are detailed by Barnett et al. (1984) and Walker 

 et al. (1987) and are only briefly summarized 

 here. 



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