Valle et al : Habitat use by Paralichthys califomicus and Paralabrax nebulifer 



653 



■O 



-o 

 c 



o 



Z 



280 

 240 



200 



20 1 



BE 



(n=870) 



20 40 60 80 100 120 140 160 180 200 220 240 260 



20 40 60 80 100 120 140 160 180 200 220 240 260 



MS 

 (n=61) 



20 40 60 80 100 120 140 160 180 200 220 240 260 



24 

 20 

 16 

 12 







6- 



4- 



10 



4- 



BE 



(n=83) 



20 40 60 80 too 120 140 160 180 200 220 240 260 

 10 

 8 



oCH 



BS 

 (n=29) 



20 40 60 80 100 120 140 160 180 200 220 240 260 



MS 



(«=21) 



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20 40 60 80 too 120 140 160 180 200 220 240 260 



Size class (mm) 



Figure 4 



Length-frequency distributions of California halibut tParalichthys califomicus) captured in unvegetated and eelgrass iZostera 

 manna ) habitats in Alamitos Bay from May 1992 through November 1995. Dark bars represent unvegetated habitats and stippled 

 bars represent eelgrass habitats. See Figure 3 for further explanation. 



Topsmelt showed a mixed pattern; they were signifi- 

 cantly more abundant in eelgrass at Marine Stadium 

 (P<0.05l but significantly more abundant in 

 unvegetated area at Belmont Shore (P<0.05). 



Stratifying by habitat and comparing abundances 

 among sites, we found that most fishes were signifi- 

 cantly more abundant at Marine Stadium or at 

 Belmont Shore (P<0.05)( Table 4). Only shiner perch, 

 giant kelpfish, and bay blenny had significantly more 

 individuals at Bay Entrance than at one of the other 

 two sites, but abundances at Bay Entrance were never 

 significantly greater than at both of the other sites. 



Discussion 



California halibut and barred sand bass 



Abundance of California halibut was habitat specific. 

 California halibut was one of the few fishes whose 

 abundance was much higher in unvegetated areas 



than in eelgrass beds. Although eelgrass blades may 

 provide shelter from predation for some inhabitants 

 (Heck and Thoman, 1981; Sogard and OUa, 1993), 

 California halibut typically avoid detection by preda- 

 tors and prey by partially burying themselves in sedi- 

 ment (Haaker, 1975). Other fiatfishes show substrate 

 preferences (Tanda, 1990; Burke et al., 1991; Rogers, 

 1992 ), and California halibut <63 mm SL prefer bare 

 sand over eelgrass in the laboratory (Drawbridge, 

 1990 ). Thus, sediments supporting eelgrass beds may 

 not be preferable for settlement. It is also possible 

 that eelgrass physically impedes halibut from set- 

 tling there. If this were solely the case, then fewer 

 halibut would be expected in eelgrass beds where dis- 

 tances between shoots were shorter (dense beds I than 

 in beds where distances between shoots were greater 

 (sparse beds). However, we found this not to be true; 

 more halibut were found in a dense eelgrass bed (Bay 

 Entrance) than in a sparse bed (Belmont Shore). 



Barred sand bass abundance was also habitat spe- 

 cific; they were almost exclusively found in eelgrass 



