FISHERY BULLETIN: VOL. 81, NO. 3 



1.6 



1.0 



 



.8 



DISTANCE 



.6 



.4 



SPECIESrTAXON 



Group 



Engraulis mordax 

 . Seriphus politus 



 Genyonemus lineatus 



• Peprilus simillimus 

 . Atherinld spp. 



• Scomber japonicus 



 Trachurus symmetricus 



 Sarda chiliensis 



. Anchoa compressa 



• Sphyraena argentea 



• Xenistius califomiensis 

 'JJmbrina roncadqr 



• Myliobatis calitornica 



• Phanerodon furcatus 



 Hyperprosopon argenteum 



 Menticirrhus undulatus 



 Amphisticus argenteus 



 Cymatogaster aggregata 



 Paralichthys californicus 



 Paralabrax nebulifer 



• Scorpaena guttata 



IV 



FIGURE 5. — Dendrogram depicting the clustering of 20 species and 1 taxon based on abundance within lampara samples. Four species 

 groups (Roman numerals) are recognized according to the Bray-Curtis index of dissimilarity (ecological distance). 



shallow depths during the night. More individuals 

 were collected during the warmer months, although 

 this relationship was highly dependent on the 

 catches of E. mordax. 



The catches of all the members of species Group I 

 were correlated with time of collection and depth 

 (negative) (Table 4). Only the abundances of E. mor- 

 dax (positive) and atherinid spp. (negative) were cor- 

 related with temperature. Scomber japonicus and T. 

 symmetricus of Group II were usually found farther 

 offshore in the study area (positive with depth). The 

 catches of S". japonicus and Sarda chiliensis were 

 positively correlated with temperature. However, T. 

 symmetricus, like many of the other species, was 

 collected in greater numbers at night, while S. chilien- 

 sis was captured almost exclusively during the day. 

 The catches of all members of species Group III were 

 negatively correlated with depth and temperature, 

 although the temperature correlation for X. calif or- 

 niensis was not significant. Six of the eight species in 

 species Group IV were negatively correlated with 



depth, although no other consistent pattern was 

 apparent. 



The occurrence and distribution of the 2 1 abundant 

 species are displayed graphically in relation to diel 

 period and depth in Figures 6 and 7. Species are pre- 

 sented in the species groups derived for the den- 

 drogram of species associations (Fig. 5). Only species 

 with >10% occurrence during the particular diel 

 period are included in the illustrations. 



During daylight periods, species Groups I, III, and 

 IV were distributed close to shore, mostly within the 

 5-11 m depth block (Fig. 6). The high variance of 

 catches during the day indicated that the species are 

 highly clumped in distribution and are probably 

 schooling at this time (especially members of Groups 

 I and III). Species of Group II were primarily found 

 offshore within the 12-16 m and 18-27 m depth 

 blocks and occurred mainly during the warmer 

 months. Group III on the other hand occurred during 

 the colder months. 



At night the distribution of species was quite dif- 



578 



