Taxonomy, Systematics, and Ecology of Helminth Parasites of the Ringed Seal, Phoca hispida Schreber, in Alaskan Waters

Authors

Ann Marie Adams, University of WashingtonFollow

Document Type

Learning Object

Date of this Version

1988

Citation

A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy

Committee Chair: Professor Robert L. Rausch

Department of Pathobiology, University of Washington, 1988

Comments

Copyright 1988, Ann Marie Adams. Used by permission

Abstract

The genus Orthosplaochnus Odhner, 1905 (Trematoda: Campulidae) was revised, with eight species recognized. Odhneriella Skriabin, 1915 was placed in synonymy with Orthosplanchnus, and Hadwenius was shown to be valid. Orthosplanchnus rossicus (Skriabin, 1915) (syn. Odhneriella rossica) was redescribed.

Inconsistencies in the diagnosis of the Anophryocephalus Baylis, 1922 (Cestoda: Tetrabothriidae) were discussed, along with the basis for generis revision. The taxonomic histories of certain genera of nematodes (e.g., Contracaecum Railliet and Henry, 1912; Dipetalonema Diesing; 1861; and Pseudoterranova Mosgovoi, 1950) were given to explain their present status.

The helminth-fauna of the ringed seal in the North Pacific was compared to those of other pinnipeds. The helminths of the ringed seal and spotted seal were qualitatively most similar, reflecting common habitats and prey. In contrast, the helminths the walrus and bearded seal differed considerably from those of the ringed seal, due mostly to their feeding on benthic organisms.

An investigation focusing on the helminths, particularly the acanthocephalans (genus Corynosoma Luehe, 1905) indicated that the distributions of the parasite-populations were overdispersed. No significant differences were shown between the populations of acanthocephalans infecting male or female seals. Also, no correlation was found between the numbers of acanthocephalans and the ages of the seals.

Analysis concerning the presence of cement on females and males of Corynosoma spp. indicated that acanthocephalans can differentiate between the sexes; that placement of cement was very specific, and that the incidence of cement on male worms was not a means of sexual selection. Rather, the occurrence of cement on males was most likely accidental and correlated with the numerical density of the worms within the spatial limits of their biotope.