ALLKN: LITTORAL FISH ASSKMHLACIK 



mates because quantitative estimates of densi- 

 ties could not be obtained for the large members 

 of this mobile species. 



Data Analysis 



Cumulative Species Curve 



The cumulative number of species in Febru- 

 ary (low fish density) and June (high fish density) 

 was plotted against the number of samples taken 

 in order to assess the adequacy of sampling. Two 

 random sequences were used for the arrange- 

 ment of the 30 samples taken each month by the 

 four methods. Each method sampled a unique 

 subhabitat within the littoral zone. Cumulative 

 species curves (reflecting presence/absence) 

 were based on a combination of methods to in- 

 sure that all possible species occupying the lit- 

 toral zone at a particular time were represent- 

 ed. 



Diversity 



Both the Shannon- Wiener information func- 

 tion (Shannon and Weaver 1949) and species 

 richness were used as measures of diversity for 

 pooled station and upper bay samples. The Shan- 

 non-Wiener index reflects both species richness 

 and evenness in a sample. 



factors— temperature (TEMP), salinity (SAL), 

 dissolved oxygen (DO), distance into the upper 

 bay from the Highway 1 bridge (DSTUPB), aver- 

 age particle size of the sediment (APRTSZ), and 

 depth of capture (DPTHCAP); the second in- 

 cluded only temperature and salinity to deter- 

 mine the amount of variation these two factors 

 accounted for alone. 



RESULTS 



Temperature and Salinity Patterns 



Water temperatures of the littoral zone at all 

 three stations increased steadily during the peri- 

 od January-June from 14°-15°C to 26°-28°C( Fig. 

 2). The temperatures remained high (>25°C) 

 throughout the summer months and then de- 

 clined gradually until November. Between No- 

 vember and December the temperature dropped 

 sharply at each station. Temperatures in the 

 pannes were generally higher than the tempera- 



30 

 20 

 10 



Cluster Analysis and Canonical Correlation 



The Ecological Analysis Package (EAP) de- 

 veloped by R. W. Smith was used at the Univer- 

 sity of Southern California Computer Center to 

 determine species associations (cluster analysis), 

 species abundance correlations to abiotic factors 

 (multiple regression subprogram), and possible 

 effects of abiotic factors on individual species 

 abundance (canonical correlation). 



The cluster analysis utilized the Bray-Curtis 

 index of dissimilarity (Clifford and Stephenson 

 1975). This index allowed quantitative cluster- 

 ing without assuming normality in the sampled 

 population. A square-root transformation of spe- 

 cies counts was done to counter the tendency of 

 this index to overemphasize dominant species. 



Canonical correlation analysis was used to de- 

 termine whether and to what extent abiotic fac- 

 tors interacted with individual species abun- 

 dances in the 39 station samples over the study 

 period. Two separate canonical correlation anal- 

 yses were made: The first run included six abiotic 



V 



o 



o 



3 



o 



a 

 a. 



E 

 e 



Panne 

 Inshore 



30 

 20 

 10 



J78FMAMJ J AS ONDJ79 

 Months 



Figure 2.— Month-to-month variation (January 1978-January 

 1979) in water temperature (°C) for the alongshore area and 

 panne at each of the three sampling stations. (* - panne dried- 

 up.) 



773 



