FISHERY BULLETIN: VOL. 73. NO. 1 



Table 5. — Occurrence of Thalassomyces marsupii on three species of amphipods taken in 

 quarterly sampling with a 1.8-m Isaacs-Kidd mid-water trawl (August 1965 to February 1967) 

 in southeastern Alaska. 



specimens collected in sampling by the National 

 Marine Fisheries Service (NMFS) in southeastern 

 Alaska, south-central Alaska, the eastern Bering 

 Sea, and the southeastern Chukchi Sea. Hoffman 

 and Yancey (1966), who reported that T. fagei 

 parasitized Thysanoessa raschii in Kachemak 

 Bay, south-central Alaska, followed the develop- 

 ment of external portions of the ellobiopsids from 

 April through June. Examination of euphausiids 

 collected during 4 yr (1962-66) of plankton 

 sampling by NMFS in southeastern Alaska indi- 

 cates that the ellobiopsids are most evident 

 during May. Maturing ellobiopsids are seen on 

 T. raschii as early as April and occasionally as 

 late as December. A similar pattern of occur- 

 rence was described by Mauchline (1966) for 

 Thalassomyces fagei on euphausiids in the North 

 Atlantic. 



Euphausia pacifica Hansen is abundant in 

 lower Chatham Strait, southeastern Alaska, but 

 is rarely parasitized by T. fagei. Euphausia 

 pacifica bears this ellobiopsid off southern Cali- 

 fornia (S. B. Collard, Marine Environmental 

 Sciences Consortium, Dauphin Island, AL 36528, 

 pers. commun.). An unidentified Thalassomyces 

 was found onE. pacifica and Thysanoessa longipes 

 Brandt in British Columbia (T. H. Butler, Biologi- 

 cal Laboratory, Fisheries Research Board of 

 Canada, Nanaimo, B.C., pers. commun.). In view 

 of the wide distribution (Jones 1964) and known 

 occurrence on at least 19 species of euphausiids 



(Vader 1973b), the British Columbia Thalasso- 

 myces is probably /a^ei. Komaki (1970) records 

 T. fagei parasitizing E. similis G. O. Sars from 

 Suruga Bay, Japan and Thysanoessa inermis 

 (Kr0yer) from the Bering Sea. 



Thalassomyces capillosus (Fage 1938) 



Amallocystis capillosus — McCauley (1962). 

 Thalassomyces capillosus — Collard (1966), Hoff- 

 man and Yancey (1966), Vader (1973a, b). 



Thalassomyces capillosus is a parasite of the 

 pelagic shrimp Pasiphaea pacifica from Coos 

 Bay, Oreg., (McCauley 1962) to Prince William 

 Sound, Alaska (Hoffman and Yancey 1966). I 

 found nearly 700 T. capillosus in varying stages 

 of development the year-round on Pasiphaea 

 collected with a 1.8-m Isaacs-Kidd trawl in 

 Chatham Strait and Lynn Canal. They were 

 most abundant during the late spring and early 

 summer, when it was not unusual to find 5 to 

 10% of the Pasiphaea in a sample parasitized; 

 in one sample (May 1965 at the southern end 

 of Chatham Strait) 47 of 115 Pasiphaea were 

 parasitized by T. capillosus. Thalassomyces capil- 

 losus is also common in British Columbia (T. H. 

 Butler, Biological Laboratory, Fisheries Research 

 Board of Canada, Nanaimo, B.C., pers. commun.). 

 Although T. capillosus are common in the north- 

 eastern Pacific, Vader (1973a) records only about 



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