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Kathryn J. Frost 

 Lloyd F Lowry 



Alaska Department of Fish and Game 

 1300 College Road 

 Fairbanks, AK 99701 



OCCURRENCE OF SOME PARASITES AND 



A COMMENSAL IN THE AMERICAN LOBSTER, 



HOMARUS AMERICANUS, FROM 



THE MID-ATLANTIC BIGHT 1 



Larvae of the nematode Ascarophis sp. were 

 reported by Uzmann (1967b) from American lobsters 

 collected from Hudson, Block, Veatch, and Corsair 

 Canyons on the edge of the continental shelf east 

 and south of southern New England (Fig. 1). Follow- 

 ing parasitological examinations of over 3,000 coastal 

 and offshore lobsters, Uzmann (1970) reported that 

 the nematode larvae were restricted almost ex- 

 clusively to offshore lobsters. Adult Ascarophis sp. 

 are intestinal parasites of fishes (Uspenskaya 1953). 

 Although coastal and offshore lobsters occur off 



Contribution No. 1277, Virginia Institute of Marine Science, 

 Gloucester Point, VA 23062. 



northern and central New Jersey, coastal lobsters 

 are scarce or absent south of Cape May NJ. There 

 is an active offshore commercial lobster fishery along 

 the edge of the continental shelf south to Norfolk 

 Canyon (Fig. 1). 



Materials and Methods 



To determine whether offshore lobsters in the Mid- 

 Atlantic Bight have larval Ascarophis sp., we ex- 

 amined the guts of 218 American lobsters, Homarus 

 americanus, collected from August 1975 through 

 March 1977. Lobsters from this region had not been 

 examined previously for parasites. 



One hundred and ninety-seven of the lobsters ex- 

 amined were caught in lobster traps or trawl nets 

 by commercial and research vessels in Norfolk and 

 Washington Canyons and from the shelf and slope 

 between and adjacent to those canyons (areas III-V, 

 Fig. 1) at depths of 73-402 m. The remaining 21 

 lobsters were caught by trawl nets from research 

 vessels off the coasts of Delaware and New Jersey 

 at depths of 57-95 m (area VIII, Fig. 1). 



The intestines and rectum were excised from live 

 lobsters on shipboard (70% of the samples) or in the 

 laboratory at the Virginia Institute of Marine 

 Science, split longitudinally, and fixed in 10% 

 Formalin 2 or in Davidson's fixative No free parasites 

 were found in the gut contents. In the laboratory, 

 the gut was transferred to 35% glycerine in 70% 

 ethanol, and part of the ethanol evaporated in a 55° C 

 oven. Pieces of the gut were then laid open, pressed 

 between two 35 x 50 mm slides, and examined for 

 the presence of cysts. This procedure followed the 

 recommendation of J. R. Uzmann 3 . 



Results 



Thirty-nine American lobsters were infected with 

 larval Ascarophis sp., encapsulated in the anterior 

 wall of the rectum (Table 1). The proportion of infec- 

 tion in 218 lobsters (17.9%) from the Mid-Atlantic 

 Bight was similar to that reported by Uzmann 

 (1967b), when examined in a 2 x 2 contingency table 

 and using Yates' correction for continuity (Elliott 

 1971). Uzmann (1967b) reported 77 infections in 314 

 lobsters (24.5%) collected east and south of southern 

 New England. However, Boghen (1978) reported in- 

 fection in the gills of 82 out of 233 lobsters (35.2%) 



2 Reference to trade names does not imply endorsement by the 

 National Marine Fisheries Service, NOAA. 



3 J. R. Uzmann, Northeast Fisheries Center Woods Hole Labora- 

 tory, National Marine Fisheries Service, NOAA, Woods Hole, MA 

 02543, pers. commun. June 1974. 



FISHERY BULLETIN: VOL. 84, NO. 1, 1986. 



197 



