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M. N. Hesselholt

Publications and source records attributed to M. N. Hesselholt.

5 recordsLinked to original sources
USGS1961

Rapid counting of nematoda in salmon by peptic digestion

The nematode parasite Anisakis sp . can be recovered, relatively unaltered, from chum salmon musculature by high temperature (52°+2°C.) peptic digestion of the flesh. The procedure, which is presented in detail, appears to be more thorough in isolating the parasite than dissection of the flesh and manual isolation of the worms. In addition, the procedure is rapid, comparatively simple, economical, and suitable for the examination of large numbers of samples. The population of Anisakis sp ., larvae in chum salmon appears to be concentrated in the ventral section of the fish, that is, below the lateral line, which ಟ್ಗ that only the ventral quarters of the fish need to be examined for estimating infection intensity.

International North Pacific Fisheries Commission B↗
USGS1958

Rapid counting of nematoda in salmon by peptic digestion

The nematode parasite Anisakis sp . can be recovered, relatively unaltered, from chum salmon musculature by high temperature (52°+2°C.) peptic digestion of the flesh. The procedure, which is presented in detail, appears to be more thorough in isolating the parasite than dissection of the flesh and manual isolation of the worms. In addition, the procedure is rapid, comparatively simple, economical, and suitable for the examination of large numbers of samples. The population of Anisakis sp ., larvae in chum salmon appears to be concentrated in the ventral section of the fish, that is, below the lateral line, which ಟ್ಗ that only the ventral quarters of the fish need to be examined for estimating infection intensity.

Special Scientific Report - Fisheries↗
USGS1957

Teratological hermaphroditism in the chum salmon Oncorhynchus keta (Walbaum)

The anomalous condition of hermaphroditism appears to be no less rare in fish than in other normally dioecious animals. Previous records of bisexuality' in the Pacific salmons, Oncorhynchus spp., are few in number despite the intensive study accorded this group. Rutter (1902) reported the condition in two king salmon ( O. tshawytscha ); Crawford (1927) reported the condition in a silver salmon ( O. kisutch ); and Gibbs (1956) described a bisexual steelhead trout ( Salmo gairdneri ) and briefly noted another instance of hermaphroditism in the king salmon. We wish to record an example of this anomaly in the chum salmon ( O. keta ).

Progressive Fish-Culturist↗
USGS1957

New host and locality record for Triaenophorus crassus forel (Cestoda: pseudophyllidea)

The adult form of Triaenophorus crassus Forel, 1868 (= T. robustus Olsson, 1893; = T. tricuspidatus morpha megadentatus Wardle, 1932) occurs as an intestinal parasite in the pike, Esox lucius L., a holarctic species of wide distribution. Preliminary life-history stages include procercoid development in copepods of the genus Cyclops followed by plerocercoid development in the musculature of a variety of coregonid and salmonid fishes. The unsightly appearance of even moderate plerocercoid infections is often sufficient to render fish unacceptable for human consumption. In the prairie provinces of Canada the incidence and intensity of T. crassus infections in the commercially important whitefishes constitute a serious economic problem.

Alaska, British Columbia, Northwest Territories↗