Global Veterinaria 11 (4): 414-419, 2013
ISSN 1992-6197
© IDOSI Publications, 2013
DOI: 10.5829/idosi.gv.2013.11.4.76137
New Record of Parasitic Praniza Larva of Gnathia pantherina; Smit and Basson, 2002;
from Arabian Gulf Greasy Grouper Epinephelus tauvina Caught
from Saudi Coastal Water of Dammam
1,2
Elsayed M. Bayoumy, 2Hanadi B. Baghdadi and 3Mohey A. Hassanain
Hydrobiology Department, National Research Center, Giza, Egypt
Department of Girls Science College, Dammam University, Saudi Arabia
3
Zoonotic Diseases Department, National Research Center, Giza, Egypt
1
2
Abstract: Praniza Larvae of Gnathia pantherina were collected fromgills, pectoral fins and mouth cavity
especially tongue and palate of Epinephelus tauvina. The total incidence (58.33%) 35 out of 60 examined fish.
The effects of feeding on fishes in the infested E. tauvina are reported and the role of gnathiids as vectors is
assessed. Ecological interactions between gnathiid larvae, client and cleaner fishes are summarized.
Identification of parasitic praniza larvae of G. pantherina were done through light and scan electron
microcopies and it characterized by large size (5.6±0.1mm, n=10). Compounds eyes large, each one is consist
of number ocelli that penta-shaped. Maxilliped consists of five-articles, proximal article the largest and
the distal four ones with plumose setae. Palp 4 times as long as wide, with three articles and article 3 with
6-8 simple setae. Other morphological features were compared with the most related described species of
the same genius. The present work recorded gills, pectoral fins and mouth cavity record as new predilection
site of these gnathiid larvae. E. tauvina and Arabian Gulf, especially off Dammam are new host and new
geographical distribution of G. pantherina.
Key words: Parasite
Isopoda
Gnathiidae
Gnathia pantherina
INTRODUCTION
Praniza larvae
Epinephelus tauvina
of commercially important fishes around the world and
cause significant economic losses to fisheries by killing,
stunting, or damaging these fishes [5]. In fact, they are
one of the most morphologically diverse of the
crustacean groups. The relation between parasite
specially crustaceans life cycle, host, host-parasite and
parasite-parasite associations are considered very
complicated biological relations [6, 7]. Isopods of the
family Gnathiidae have free-living adults and parasitic
juveniles feeding on the blood and tissue fluids of teleost
and elasmobranch fishes [8].Gnathiids infest many
species of marine and estuarine teleosts and
elasmobranchs [3,9].
Marine fishes are parasitized by a variety of
copepods so parasitic copepods are increasingly serious
problems in cultured fish and can also impact wild
Each parasite has two-sided effect on host,
one beneficial to the host and the other is harmful. To find
out the point of benefit or harm, we must know the exact
structures of this parasite. Parasites are becoming
recognized as significant players in the evolutionary game
and are being seen as excellent model systems for general
evolutionary studies [1]. Most parasitic crustaceans
spend part of their life cycle as particularly male ones,
where the fertilized female are parasitic to lay their eggs
and to maintain the continuation of their life and
developmental stages in the water column [2-4].
Crustaceans are increasingly serious problems
in cultured fish and can impact wild populations.
Isopods are crustaceans that associate with many species
Corresponding Author: Elsayed M. Bayoumy, Hydrobiology Department, National Research Center, Giza,
Egypt and Department of Girls Science College, Dammam University, Saudi Arabia.
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Global Veterinaria, 11 (4): 414-419, 2013
RESULTS
populations [3, 10, 11]. Many of species parasitic
copepods have long been recognized to have the
potential to affect the growth, fecundity and survival of
wild hosts [12-14]. Arabian Gulf represents one of the
most important sources of animal protein in Saudi Arabia
as it contains numerous types of fishes. Groupers are one
of the most important of these fish and it is also among
the highest priced fish. Literatures on copepod parasites
of Arabian Gulf grouper are relatively rare. For that
reason, the present work aims to study the prevalence and
description of gnathiid isopod from Greasy Grouper
Epinephelus tauvina caught from Saudi coastal
waters off Dammam through light and scan electron
microscopes.
Gnathiid Prevalence and Intensity: The obtained results
indicated that (58.33%) 35 out of 60 examined E. tauvina
found infested by gnathiid parasite. The intensity of
infestation ranged 15-35 (22) parasites/infested fish with
weight range 150-230 g. While, it ranged 5-12 (8)
parasites/infested fish with weight range 90-150 g.
Clinical Examination: Female gnathiid parasites were
collected from the gills, pectoral fins and mouth cavity
especially tongue and palate of upper jaw (Fig. 1A-C).
Abundance of mucus surrounds the gill filament and
the inner surface of the operculum and their erosion
(Fig. 1B and C). Moreover, tongue and palate of upper
Jaw of the infested fish showed multifocal hemorrhagic
spots below and between the pectoral and pelvic fins
(Fig.1A).
MATERIALS AND METHODS
Fish: A total of 60 Arabian Gulf greasy grouper
E. tauvina were purchased freshly-caught from the
local fish market in Dammam area for parasitological
examinations.Fish samples were collected at a period
extended from January to February 2012.
Description: Total length of Gnathia praniza larva
(5.6±0.1mm, n=10) 3.8-5.9 mm.
Cephalosome: Posterior margin straight, slightly wider
than anterior margin, almost as wide as long, lateral
margins slightly convex (Figs. 1D and 2B). Many sensory
pits and three pairs of simple setae are on dorsal surface
of cephalosome (Figs. 1D, 2A and B). Compounds large
eyes, well developed, oval-shaped, on lateral margins of
cephalosome. Each one consists of a number ocelli that
penta-shaped (Fig. 2A and B). Medio-anterior margin
of cephalosome is straight with lateral concave
excavation to accommodate first articles of antennae
(Figs. 1D and 2B).
Clinical Examination: Fish samples under investigation
were grossly examined for determination of clinical signs
and any external parasite [15].
Parasitological Preparations: For light microscopy,
Parasites were collected from the gills, branchial chambers
and mouth cavity of the investigated fish species.
The copepods were preserved in 70% ethyl alcohol.
They were then dissected and mounted in lactophenol as
temporary slide preparations and examined on an
Olympus compound microscope.
For scan electron microscopy, gnathiids were
rehydrated in a descending sequence of acetone and
washed in distilled water to clean them of any salt and
debris, according to techniques described by
Smit and Van As [14], the gnathiid larvae were
post-fixed in1% osmium tetroxide (Oso4) for one hour,
then dehydrated through graded acetone and dried in a
CPD 750 critical-point-dryer using liquid CO2.
The specimens were whole-mounted on an aluminum stub
and fixed by double- phase sticker. The specimens were
then coated with gold palladium in a sputter
coating unit (Polaron E5000; Polaron Equipment,
UK) and examined using a scanning electron microscope
(JEOL SEM T330; JEOL, Japan) operating at 20 Kev.
Labrum: semicircular with apical process, truncate
posterior margins, anterior margin concave. Ventral part of
it covers mandibles dorsally and laterally (Fig. 2B and C).
Antennae: Both antennae are approximately of equal size
(Fig. 2B). Antenna 1 with three peduncle articles, a pair of
feather-like setae on articles 1 and 2 respectively,
article 3 largest with hair-like setae. Antenna 2
with four 4 peduncle articles and the fourth one is the
largest.
Mandible: Long, almost the same length as cephalosome,
more than twice as long and wide, curved inwards with
seven to nine processes (Fig. 2B and C). Apex conical and
incisor present, terminating in acute point.
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Global Veterinaria, 11 (4): 414-419, 2013
Fig. 1: A-C:
Photograph
of E. tauvina on the anterior-ventral view. A: Buccal cavity infested
with Gnathiid Isopods showing extensive areas of erosion and hemorrhages; B and C: Heavy
infested gills and branchial chambers; D: light photomicrograph of
G. pantherina, eye (e),
first antenna (fa), Pelion (p), pleotelson (pl), parapod (pp), ventral cephalosome (vc) and uropods
(up).
Fig. 2: Scanning electron micrographs of G. pantherina. A: ventral view of whole parasite; B and C: ventral view of
cephalosome and D: dorsal view of pleoteson, eye (e), first antenna (fa), gnathopod (g), mandible (m), maxillule
(mx), Pelion (p), paragnaths (pa), pleotelson (pl), parapod (pp), second antenna (sa), ventral cephalosome (vc)
and uropods (up).
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Global Veterinaria, 11 (4): 414-419, 2013
Maxilliped: Five-articles, proximal article the largest and
the distal four ones with plumose setae (Fig.2B and C).
Palp 4 times as long as wide, with three articles, first article
acute with 3-5 small teeth and article 3 with 6-8 simple
setae.
dorsal and ventral sides of robust seta.Pereopods 3 to 6
similar to pereopod 2 in basic form, differ in setation,
shape and number of tubercles.
Uropod: Rami extending beyond apex of pleotelson,
endopod longer and wider than exopod, both with long
simple setae, pectinate scales on dorsal area of uropods
(Fig. 2D).
Gnathopod: Smaller than pereopod, setae on the basis are
feather-like (Fig.2D).
Pylopod: Four articles; article 1 and 2 fused. Article 1
broad, robust, with a single simple seta mid-dorsally and
short curved seta dorso-laterally. Article 2 and 3 each one
of them with two to four simple setae distally. Article 4 is
small with one to two simple setae.
DISCUSSION
Marine fishes are parasitized by a variety of isopods
so they represent serious problems in cultured fish and
can also impact wild populations [16]. In the present work,
the obtained gnathiid parasite collected from gills,
branchial chambers and mouth cavity of the examined
fish, while it previously obtained by Smit and Basson and
Smit et al., [17, 18] from the body of the fish is preferred,
followed by the dorsal fin, pectoral fin and anal fin.
The previous author attributed the presence of the
gnathiid parasite on the caudal and pelvic fins as
sampling artifact. Therefore, the present study improve
that it was not artifact, gnathiid can infest other
sites and sites of infestation that recorded in
the present study could be as new predilection site to
gnathiid.
Concerning the gnathiid prevalence (58.33%) and
intensity (8-22 parasites/infested fish), approximately the
same results were obtained by Jones and Grutter [9] and
the attributed they change of parasite prevalence and
intensity to host type and seasons (temperature). With
regard to the damage (mucus, gill erosion and multifocal
hemorrhagic spots) caused by gnathiids, allow us to
conclude that the result of a double parasitic action;
mechanical damage on the skin, gills and pharyngeal
mucosa [19-21]. Additionally, the gnathiids are blood
sucking parasite, so it has a well developed and strong
mouth parts where, the mouthparts of the parasite
penetrate the epidermis and cause hemorrhage from
vessels in the dermis [21-23]. The feeding times for the
three praniza stages of G. africana are approximately 2, 3
and 10 h [17, 18]. G. piscivora that attach to the skin leave
the host within 2–4 h, while those that attach to gills and
the walls of the gill cavity remain for 1 or more days
[24, 25].
The lack of detailed description of Gnathia species
before from Arabian Gulf or from similar host makes it
difficult to provide comprehensive comparison with
those already described. The present parasite has
measurements larger than that of both G. pantherina [17]
and G. africana [14] larva. According to Smit and Basson
Pereon: Almost one and half times as long as wide,
swollen, round, structure between pereonites 4-6 and
wider than cephalosome. Pereonite 6 dorsally visible,
small with rounded posterior margin and pereonite 1 fused
with cephalosome.
Pleon: Pleon and pleotelson more than a half of total
length (Figs. 1D and 2A). Five sub-equal pleonites
dorsally visible, epimera not distinct, short hair-like setae
randomly distributed on pleonites.
Pleotelson: Triangular, its base is wider than length and
lateral margins tapering in two steps towards apex,
its dorsal surface with twopairs of simple setae and
pectinate scales, distal apex terminating in pair of long
simple setae (Fig. 1D).
Pereopods: Pereopod 2 basis elongated, with four
to nine feather-like setae and short simple setae anteriorly,
two to four posterior simple setae (Figs. 1D and 2).
Ischium hastwo-thirds length of basis, three to five
anterior simple setae and three simple setae posteriorly.
Merus half the length of ischium with anterior bulbous
protrusion, three simple setae on bulbous protrusion,
posterior margin with two to three tooth-shaped
tubercles.Carpus of almost the same size and shape as
merus but without anterior bulbous protrusion,
posterior margin with eight to ten tooth-shaped tubercles,
simple setae and a single feather-like seta. Propodus is
about twice the length of carpus, tooth-shaped tubercles
on posterior margin, two robust denticulated setae
situated on middle and distal part of posterior margin
respectively, single simple seta and one featherlike seta
anterio-distally. Dactylus half the length of propodus,
terminates in sharp posterior pointing unguis, robust seta
on posterior side proximal to unguis, few simple setae on
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Global Veterinaria, 11 (4): 414-419, 2013
[17] the basic morphology of G. pantherinais very similar
to that of G. africana larva. The present material
pleotelson triangular, its base wider than length and
lateral margins tapering in two steps towards apex that is
similar to G. africana while, that of G. pantherina
concave antero-lateral margins. The parasite under
discussion can however, be distinguished from G.
africana by the flowing characteristics. The first palp
article of the maxilliped of G. africana has 5 to 7 teeth Vs
6-8 of the present material. It can also be distinguished
from G. pantherina, where its pereopod with 4-9 featherlike setae and short simple setae anteriorly; two to four
posterior simple setae while that of G. pantherina with
single feather-like bristl and 2-4 simple setae anteriorly.
From the previous discussed points, the present
parasite is more relatively closest similar to G. pantherina
than to G. africana. The gills, pectoral fins and mouth
cavity record as new predilection site of this gnathiid
larvae. E.tauvina and Arabian Gulf, especially off
Dammam are new host and new geographical distribution
of G. pantherina.
7.
8.
9.
10.
11.
12.
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