7704

• UCREFRP Catalog Number: 7704
• Author: Wolf, D. J.
• Title: Editor
• USFW Year: Series
• USFW - Doc Type: 1977
• Copyright Material: YES

ZOOLOGY

99-B

and a key to the genera of parasites was prepared as well as
diagnosis and illustration of each species.
New synonymies proposed in the Monogenea were: the
genus Syncleithrium Price, 1967, as a junior synonym of Ac-
tinocleidus Mueller, 1937; and the species Dactylogyrus atro-
maculatus Mizelle, 1938, as a junior synonym of Dactylogyrus
microphallus Mueller, 1938; Dactylogyrus heterolepis Hanek,
Molnar and Fernando, 1975, as a junior synonym of Dactylo-
gyrus banghami Mizelle and Donahue, 1944; Dactylogyrus
pyriformis Mizelle and Klucka, 1953, and Dactylogyrus vannus
Mizelle and Klucka, 1953, as junior synonyms of Dactylogyrus
cornutus Mueller, 1938. Synonymy proposed in the Cestoda
was the genus Corallotaenia Freze, 1965, as a junior synonym
of Corallobothrium Fritsch, 1886.
In general, the parasites showed a high degree of host spec-
ificity: 66 (78%) of the Monogenea, 14 (74%) of the Digenea and
17 (74%) of the Cestoda were recovered from only one host
species; 23 (15%) of the Monogenea, 3 (16%) of the Digena and
6 (26%) of the Cestoda were recovered from 2 host species;
only 6 (7%) of the Monogenea and 2 (10%) of the Cestoda were
recovered from more than 2 host species. When multiple host
species were infected by a single parasite species, infections
were limited to fishes of the same family.
Order No. 77-14,676, 229 pages.

THE BIOLOGY OF TWO SPECIES OF ECHINORHYNCHUS
(ACANTHOCEPHALA) FROM MARINE FISHES IN OREGON

MILLER, Richard Leo, Ph.D.
Oregon State University, 1977

Two species of acanthocephalans which parasitize marine
fishes along the Oregon coast were studied during 1972-73.
Echinorhynchus !1;adi infections were observed in Dover sole,
Microstomus pacificus and Rex sole, Glyptocephalus zachirus
and constituted new host records for the parasite. The adult
worm was redescribed since the acanthocephalan from the two
pleuronectid flatfishes is identical to E. !1;adi as described in
the literature, except for the regular occurrence of 17 rows of
longitudinal hooks on the proboscis.
Echinorhynchus sp., found only in the Pacific staghorn
sculpin, Leptocottus armatus, is an undescribed species and
resembles only E. laurentianus which parasitizes pleuronectid
flatfishes on the east coast of North America. The adult worm
was described.
Echinorhynchus sp. was observed in L. armatus from all
sampling sites and in Yaquina Bay fish throughout the year.
The prevalence and intensity of infection in Yaquina Bay fish
greater than 100 mm total length were similar in all size
classes and substantially higher than in young fish.
A non -seasonal parasitic cycle was operating and restricted
in Yaquina Bay and EChinorhynchus sp. was being acquired and
lost from L. armatus throughout the year. The lack of a sea-
sonal cycle was indicated by: little variation in monthly preva-
lence and intensity of infection; the monthly consistency of
average worm length; the occurrence of small immature worms
all months and the presence of all stages of sexual development
in female worms each month.
Echinorhynchus !1;adi infections were found in all samples of
M, pacificus and G. zachirus. Although the prevalence and in-
tensity of infection of E. gadi generally increased with fish
length and age for both hosts, no apparent seasonality of infec-
tion was observed, However a seasonal maturation cycle was
evident by the growth of worms and the sexual development of
the worm population. Only small immature parasites of both
sexes were found in the spring and only large mature individu-
als were collected in the fall and winter.
The seasonal cycle o[ E, gadi in M. pacificus and G. zachirus

was as follows: a single period of new infection acquisition
during the spring onshore migration, followed by growth and
mating during the summer and maturation, egg production and
eventual elimination of spent adult worms during the fall and
winter. The seasonal cycle is the first reported for a marine
acanthocephalan in which migration of the definitive host and
the restricted distribution of the unknown intermediate host
(zone of infection) are primary factors controlling the distribu-
tion of the parasite.
Differences were observed between M, pacificus and Q.
zachirus in prevalence, intensity, parasitq growth, parasite sex
ratios and number of unisexual infection~;' The observed dif-
ferences are probably related to habitat preferences and phys-
iological factors affecting the host-parasite relationship of ~.
gadi and M. pacificus.
The life cycle of Echinorhynchus sp. was completed experi-
mentally in the laboratory. Eggs ingested by the amphipod in-
termediate host Anisogammarus confervicolus hatch and the
acanthor penetrates the intestine within two days. The develop-
ing acanthella, surrounded by a thin capsule of amphipod hemo-
cytes, remain attached to the intestinal serosa for about ten
days and then drop free into the hemocoel. T~e acanthella be-
comes infective in 33 days at 230C. Acanthors of E. lagenifor-
mis and E. gadi were always encapsulated and melanized in ~.
confervicolus and did not dE;velop,
Order No. 77-15,368, 118 pages.

GALVANOTROPIC ORIENTATION OF GOLDFISH
(CARASSIUS AURATUS)

WOLF, Daniel Jay, Ph.D.
University of Illinois at Urbana-Champaign, 1976

The orientation of goldfish (Carassius auratus) with respect
to the flow of direct current (galvanic current) was observed
with the aid of video tapes. The consequence of 15 seconds of
direct current stimulation was found to be a biphasic tropism.
At low stimulus intensities goldfish orient toward the cathode
pole of the current source, while at high intensities, anodic
orientation is evident. The roles of subject size and electrical
properties of the water, in determining the response of subjects
to a given stimulus intensity, were also investigated. A linear
relation between the precision of orientation of subjects (mea-
sured as the resultant vector of 10, 12, or 24 trials) and the
potential difference along the length of the subjects was deduced.
The partition of electric current flow between the subjects and
surrounding water is also discussed with respect to the problem
of determining the effect on an individual, of an externally ap-
plied voltage gradient in a tank of water.
In addition to the quantitative study of orienting precision of
intact animals, a study was made of the orientation of animals
that were neurosurgically altered. The principal findings in-
cluded a loss of anodic orientation at high intensities for fish
with spinal transections, and a significantly decreased preci-
sion of anodic orientation (at high intensities) [or fish with bi-
lateral labyrinthectomies. A similar decrease in anodic orient-
ing precision was found for fish that had Xylocaine solution
irrigated through the otic canals, compared with shams (saline
irrigation).
These studies have led to two conclusions concerning the
galvanotropic orientation of goldfish. The precision of orien-
tation is a linear function of the potential difference along the
length of fish, and the cathodic and anodic phases are under
control of different neural systems. The involvement of
labyrinthine organs in the expression of galvanotropic orien-
tation is discussed in relation to the phenomenon of electro-
reception by fish species possessing specialized electrore-
ceptors. Order No. 77-9243, 187 pages.