ALLEN: LITTORAL FISH ASSEMBLAGE 



a. 



15 - 



10 - 



Random Seq. #2 



'•= 5 " 



Number of Samples 



15 - June 



_ 10 - 



o 



Z 



5 - 



Number ol Samples 



Figure 4.— Cumulative number of species as a function of the 

 number of samples of all methods at stations 1-3 combined in 

 upper Newport Bay for two different months (February and 

 June 1978) during the study period. Curves were generated by 

 two random sequences for each month. 



that the range of fish species in the area had been 

 adequately sampled by the four methods. Ac- 

 cumulation of species in June, however, was gen- 

 erally more rapid than in February. 



Seasonal Abundance and Diversity 



Fish abundance and diversity fluctuated 

 markedly during the 13 mo of the study (Fig. 5). 

 As a whole, the ichthyofauna of the littoral zone 

 showed increased species richness from 10 spe- 

 cies in January to 16 species in July 1978. The 

 number of species was elevated (>14) for the 

 entire spring-summer period from May to 

 August 1978. Richness then decreased through 

 the fall, reaching its lowest point of six species in 

 December 1978. Diversity H' values fluctuated 

 in a pattern opposite to that of species richness. 

 H'\ decreased during the summer from a high in 

 May of 1.76 to a low in June of 0.44. H' B also de- 

 creased sharply in summer but unlike H'\ con- 

 tinued to decline for the remainder of the study. 

 Both the number of individuals and biomass be- 

 gan to increase dramatically during May 1978 



and reached peaks of 21,907 individuals and 21.7 

 kg in June. Both numbers and biomass decreased 

 in August with number of individuals increasing 

 again in September. Biomass declined once 

 again in September during a period of rainfall 

 and then increased in October. In the months 

 from October 1978 to January 1979 a rapid de- 

 cline in both numbers and biomass was evident 

 and was especially pronounced from November 

 to December. A greater number of individuals 

 (992-579) and much greater biomass (4,692-597 

 g) was obtained in January 1979 than in January 

 1978. 



Species Associations 



Cluster analysis based on individual samples 

 yielded five species groups which, upon further 



2.0 

 x 1.0 



° » 10 

 Z o> 

 a 



§ 6 



C 



. O ' 

 O 



H Diversity 



Number of Species 



zJS 



cT 16 

 o 



X 



~~ 12 



in 



E 

 a 



en B 



c 



Number of 

 Individuals 



o> 



Biomass 



1 1 1 ! 



J78 F M A M J J A S O N D J 79 

 Months 



Figure 5.— Monthly variation (January 1978-January 1979) in 

 total number of species, diversity H' (for numbers, Hn, and 

 biomass, H B ), number of individuals and biomass (g) for fishes 

 collected by all methods at stations 1-3 combined in the littoral 

 zone of upper Newport Bay. 



777 



