Comparative Parasitology 67(2) 2000 - Peru State College

Comp. Parasitol.
67(2), 2000 pp. 253-254
Research Note
RESEARCH NOTES 253
Colobomatus embiotocae (Copepoda: Philichthyidae) from Shiner
Perch, Cymatogaster aggregata (Osteichthyes: Embiotocidae) in
Canadian Waters
SHELLEY F. JEPPS AND TIMOTHY M. GOATER'
Biology Department, Malaspina University-College, Nanaimo, British Columbia, Canada V9R 5S5 (e-mail:
goatert@mala.bc.ca)
ABSTRACT: During an examination of the parasitic
crustacean fauna of shiner perch, Cymatogaster aggregata
(Embiotocidae) from eastern Vancouver Island in
Nanaimo, British Columbia, Canada, the copepod, Colobomatus
embiotocae Noble, Collard, and Wilkes,
1969 (Philichthyidae), was noted in the sensory ducts
of the preopercular cephalic canals. Prevalence and
mean intensity of C. embiotocae were 59.2% and 1.36
± 0.57, respectively. This parasite was also recovered
from 68.4% (mean intensity = 1.62 ± 0.65) of shiner
perch sampled near Bamfield Marine Station on the
western coast of Vancouver Island. The high prevalence
of C. embiotocae probably reflects increased
transmission resulting from the aggregation behavior
of the fish host. These results establish a range extension
for C. embiotocae in C. aggregata to include Canadian
Pacific waters.
KEY WORDS: Colobomatus embiotocae, Copepoda,
shiner perch, Cymatogaster aggregata, British Columbia,
Canada.
Members of the poecilostome family Philichthyidae
are endoparasitic copepods that occupy
the subcutaneous spaces associated with
the sensory canals of the skull bones and lateral
line of marine fishes (Kabata, 1979). They are
highly specialized parasitic copepods, with pronounced
sexual dimorphism and females exhibiting
reduced organs of attachment, reduced appendages,
and bizarre morphological processes
projecting from their bodies.
The richest genus of this family, Colobomatus,
is recorded from a diversity of marine teleosts
and elasmobranchs (Kabata, 1979; West,
1992). Colobomatus embiotocae Noble, Collard,
and Wilkes, 1969, was first described from shiner
perch, Cymatogaster aggregata Gibbons,
1854, and was found infecting several other spe-
Corresponding author.
cies of embiotocid fishes in California and
Oregon in the United States and in Mexico (Noble
et al., 1969). Samples were not collected
from Canadian waters, though the range of C.
aggregata, among the most widely distributed
embiotocid fish species, extends from Port
Wrangel, Alaska, U.S.A., to Quintin Bay, Baja
California, Mexico (Odenweller, 1975). Arai et
al. (1988) did not find C. embiotocae during
their study of metazoan parasites of C. aggregata
from British Columbia. To date, the only
species of Colobomatus recorded from Canadian
waters is Colobomatus kyphosus Sekerak, 1970,
from Sebastodes alutus Gilbert, 1890, and several
species of Sebastes (Sekerak, 1970; Sekerak
and Arai, 1977; Kabata, 1988).
Females and males of C, embiotocae have 11
body segments; in the female the fourth and fifth
are fused. The average length for females and
males is approximately 3.7 mm and 1.2 mm, respectively
(Noble et al., 1969). Diagnostic morphological
features distinguishing the female
parasite from other species of Colobomatus include
the caudal furcae with a spine on their
inside lateral surfaces, the egg-laying apparatus
with a bulbous structure equipped with a flagellate
seta, and 3 eyes arranged in a compact cluster.
Males of C. embiotocae are distinguished on
the basis of their 6-segmented first antennae and
1-segmented mandibles (Noble et al., 1969).
During an investigation of the parasitic crustacean
fauna of C. aggregata from Piper's Lagoon,
Nanaimo, British Columbia, males and females
of C. embiotocae were noticed infecting
the sensory canals of the skull. A total of 76 C.
aggregata was seined from the littoral region
during March 1996, returned to the laboratory,
and killed in concentrated anesthetic (MS-222),
and their cephalic sensory canals and lateral
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