O100 

 E 90 

 U 80 

 u. 70 

 Z 60 

 H 50 

 5 40 

 U 30 



cc 



UJ 



Q. 



20 

 10 



OlOOr 

 £ 90 



80 

 ff 70 



1 60 

 (- 50 

 z 40 

 O 30 

 £ 20 



Q. 10 



gioo 



u 



in 



90 

 80 

 70 

 £ 60 



\- 50 

 g 40 

 y 30 

 2 20 



°> 10 



H. aduncum 



510 



1620 26 30 36 40 



TOTAL LENGTH (CM) 



M.sebastis 



46 



510 



1620 2630 3640 



TOTAL LENGTH CM) 



46 



Lepeophtheirus sp. 



510 



-4T 



q100 

 UJ 90 

 O 80 

 £ 70 

 Z 60 

 t 50 



5 *oi- 



(3 30 

 £ 20 

 Q. 10 



O100 



£ 90 



O 80 



£ 70 



Z 60 



K 50 



Z 40 

 ui ^ v ' 



O 30 

 £ 20 

 Q- 10 



q100 

 UJ 90 

 O 80 

 £ 70 

 Z 60 

 H 50 

 40 

 30 

 20 

 10 



UJ 



UJ 



o. 



N. girellae 



./' 



510 



1620 

 TOTAL 



2630 3640 



LENGTH (CM) 



Myxozoa sp. 



46 



/ 



/ 



5-10 



1620 2630 3640 



TOTAL LENGTH (CM) 



H. sebasta 



46 



/ 



/ 



./ 



510 

 H. spinulus 



1620 2630 3640 



TOTAL LENGTH (CM) 



46 



1620 2630 36 40 



TOTAL LENGTH (CM) 



46 



FIGURE 2. — The relationships between host length and percent prevalence of infection by seven parasite species from olive rockfish 

 taken off Diablo Cove, Calif. All relationships show significant difference at P =£ 0.05. See Table 3 for numbers offish examined in each 

 length interval; see Table 1 for the number of specimens per size class. 



ward fish and away from zooplankton (Love and 

 Westphal 1981) probably accounts for the increase 

 in Hysterothylacium aduncum infections, as fish 

 are thought to be intermediate hosts for this 

 species (Margolis 1970). The prevalence of 

 Clauella parva was the opposite — it was found 

 only in hosts <10 cm in length. Clauella parva 

 attaches to dorsal, anal, and caudal fin rays. 

 Perhaps structural barriers (such as ray diameter 

 or surface characteristics) or increased water flow 

 over the fins in larger fish prevent infection. Simi- 



lar infection patterns were noted in Sebastes 

 alutus and S. caurinus by Sekerak (1975). 



Among species with seasonal patterns of infec- 

 tion, winter maximum infections were exhibited 

 by Lepeophtheirus sp., Holobomolochus spinulus, 

 the gallbladder myxozoans, and Deretrema 

 cholaeum. The first three forms listed have direct 

 life cycles. Olive rockfish are winter and early 

 spring spawners (December-March) with internal 

 fertilization occurring from November to Feb- 

 ruary. It is possible that these parasites time their 



534 



