On the development of a parasitic copepod, Lamproglena clariae Fryer, 1956 (Copepoda, Lernaeidae) infecting the sharp tooth catfish, Clarias gariepinus

Crustaceana ◽  
2013 ◽  
Vol 86 (4) ◽  
pp. 416-436 ◽  
Author(s):  
G. N. Madanire-Moyo ◽  
A. Avenant-Oldewage

The postembryonic development of the gill parasite, Lamproglena clariae, infecting the sharp tooth catfish, Clarias gariepinus was established from egg culture and artificial infection of fish under laboratory conditions. Like most fish parasitic copepods, L. clariae has a direct life cycle utilizing only a single fish host species. Adult post metamorphosis females produce two egg strings. The mean number of eggs in each egg string was 52. Three naupliar and first copepodid stages were obtained in culture while two copepodid stages, cyclopoid and adult specimens were obtained after artificial infection of catfish in aquaria. First stage nauplii were globular in shape and densely filled with yolk. Nauplii lacked a perforation for the mouth and masticatory parts of the appendages, all of which indicate that they do not feed. Body architecture of the first copepodid stage of L. clariae is similar to that of all other copepods in the number and kind of somites: a cephalothorax with five appendages, three thoracic somites, one abdominal somite and furca rami. This seems to be a conserved morphology among the copepods. The three naupliar and three copepodid stages are described and compared to related copepods.

1987 ◽  
Vol 65 (6) ◽  
pp. 1331-1336
Author(s):  
Z. Kabata

The morphology of the developmental stages of Neobrachiella robusta (Wilson, 1912) (Copepoda: Siphonostomatoida) is described. The copepod is parasitic on the gill rakers of Sebastes alutus (Gilbert, 1890) (Teleostei: Scorpaeniformes). The life cycle of this copepod consists of a copepodid stage, followed by four chalimus stages and a relatively long preadult stage, which undergoes extensive metamorphosis. The copepods aggregate on the outer row of long gill rakers of the first gill arch, as many as 97% of them being attached to these rakers. Some of the rakers become distorted, but a connection between the presence of N. robusta and these abnormalities could not be established.


Author(s):  
Wouter Koch ◽  
Peter Boer ◽  
Johannes IJ. Witte ◽  
Henk W. Van der Veer ◽  
David W. Thieltges

A conspicuous part of the parasite fauna of marine fish are ectoparasites, which attach mainly to the fins or gills. The abundant copepods have received much interest due to their negative effects on hosts. However, for many localities the copepod fauna of fish is still poorly known, and we know little about their temporal stability as long-term observations are largely absent. Our study provides the first inventory of ectoparasitic copepods on fish from the western Wadden Sea (North Sea) based on field data from 1968 and 2010 and additional unpublished notes. In total, 47 copepod parasite species have been recorded on 52 fish host species to date. For two copepod species parasitizing the European flounder (Platichthys flesus), a quantitative comparison of infection levels between 1968 and 2010 was possible. Whereas Acanthochondria cornuta did not show a change in the relationship between host size and infection levels, Lepeophtheirus pectoralis shifted towards the infection of smaller hosts, with higher infection levels in 2010 compared to 1968. These differences probably reflect the biology of the species and the observed decrease in abundance and size of flounders during the last decades. The skin-infecting L. pectoralis can probably compensate for dwindling host abundance by infecting smaller fish and increasing its abundance per given host size. In contrast, the gill cavity inhabiting A. cornuta probably faces a spatial constraint (fixed number of gill arches), thus limiting its abundance and setting a minimum for the host size necessary for infections.


2016 ◽  
Vol 8 (3) ◽  
pp. 281-285 ◽  
Author(s):  
Chidozie Nwabuisi OKOYE ◽  
Udensi Maduabuchi IGWEBUIKE ◽  
Anietie Francis UDOUMOH ◽  
Chinadindu Tochukwu OKEREKE

Testicular morphology and sperm motility were evaluated in cultured Clarias gariepinus (n = 25) purposively assigned to five groups according to their age. The results showed that the testes were paired, elongated, dorso-ventrally flattened structures, situated in the caudal aspects of the body cavity. The mean length of both right and left testes increased linearly with age, being significantly (p < 0.05) higher at 6 months than at 4 and 5 months of age, and also significantly (p < 0.05) higher at 8 months than at 6 months of age, while the mean weight and organo-somatic index of the catfish testes increased linearly until 6 months of age, after which no significant (p > 0.05) increase in the testicular weight and organo-somatic index was observed. Unidirectional progressive movement of spermatozoa was detected in the milt of C. gariepinus at 6, 7 and 8 months of age, but sperm cells were non-motile at 4 and 5 months of age. Histological sections showed seminiferous lobules, whose germinal epithelia were characterized by many cysts enclosing clones of sperm cells. Each cyst enclosed a clone of sperm cells at an identical stage of spermatogenesis. Spermatids and spermatozoa were present in the lumen of the seminiferous lobule. The obtained results indicate that the morphology of the testes of C. gariepinus is similar to the testes of members of the order Siluriformes, but sexual maturity and production of motile spermatozoa may be achieved at 6 months of age in the African catfish.


Parasitology ◽  
1984 ◽  
Vol 89 (2) ◽  
pp. 209-220 ◽  
Author(s):  
C. R. Kennedy

SummaryFollowing recent suggestions that a peaked host age–parasite abundance curve, concomitant with a decline in the degree of dispersion of parasites in the older age classes of hosts, can provide evidence of parasite-induced host mortality, the changes in mean abundance and over-dispersion of metacercarial stages of Diplostomum spathaceum, D. gasterostei, Tylodelphys clavata and T. podicipina in relation to fish age were studied in a field locality. The mean parasite burden of D. spathaceum, D. gasterostei and T. clavata increased with host age and the maximum mean burden was found in the oldest hosts. The variance to mean ratio also increased in D. gasterostei, but decreased in the oldest hosts in D. spathaceum and T. clavata. It is concluded that this decrease could be due to parasite-induced host mortality but could equally be due to death of parasites within the host or to changes in infection rate or could be a reflection of the small sample size of the oldest fish. The mean burden of T. podicipina declined gradually with host age, but the variance to mean ratio remained constant and it is concluded that this could be explained by death of the parasites within the host. None of these data or data from other localities provided clear and unambiguous evidence of host mortality induced by heavy infections of any of the four species, although they are consistent with such mortality and do not refute such a possibility. It is concluded that it may be just as difficult to detect and unequivocally demonstrate parasite-induced host mortality in metacercarial digenean–fish host systems as in any other parasite–host systems.


Author(s):  
S. C. Johnson ◽  
L. J. Albright

Development, growth, and survival data derived from laboratory experiments are provided for Lepeophtheirus salmonis, a common ectoparasite of wild and sea-farmed salmonids. The mean development time of eggs was 419·1 hours (17·5 days) at 5°C, 207·1 hours (8·6 days) at 10°C, and 130·8 hours (5·5 days) at 15°C. Development from the first nauplius to the infectious copepodid stage took 222·3 hours (9·3 days) at 5°C, 87·4 hours (3·6 days) at 10°C, and 44·8 (1·9 days) hours at 15°C. Development from the egg to the adult male took 40 days, and from the egg to the adult female 52 days at 10°C. No egg development occurred at 10‰ salinity. At 15‰ eggs developed but failed to produce active nauplii. At higher salinities (20–3‰) active nauplii were produced, but copepodids were only obtained at 30‰. Copepodids survived for less than 1 day in waters with a salinity of 10‰ or less. At higher salinities (15–30‰) and temperatures of 5,10, and 15°C average survival times ranged between 2 and 8 days.


Crustaceana ◽  
1997 ◽  
Vol 70 (8) ◽  
pp. 911-919 ◽  
Author(s):  
Kunihiko Izawa

AbstractThe copepodid stage of the parasitic copepod Peniculisa shiinoi Izawa, 1965 (Siphonostomatoida, Pennellidae), parasitic on the fins of a puffer fish, Canthigaster rivulatus, is described based on specimens reared from eggs. This is the only free-swimming larval stage of P. shiinoi. The copepodid is distinctly smaller than those of the known pennellids. However, the dispensability of the free-swimming nauplius stage is independent of the egg-size. The copepodid antennae of the pennellids are certainly uniramous. The setation of the rami of the copepodid legs varies among pennellids.


Parasitology ◽  
1982 ◽  
Vol 84 (1) ◽  
pp. 41-47 ◽  
Author(s):  
D. M. Gordon ◽  
M. E. Rau

SUMMARYRegular samples made on the 1978 cohort of brook sticklebacks (Culaea inconstans) from a swamp in Ile Perrot, Quebec, Canada were examined for Apatemon gracilis metacercariae. The prevalence of the parasite rapidly reached 100% in the fish population. The mean parasite burden increased from zero to a plateau of about 44 parasites/fish. Over-dispersion of the frequency distribution of parasites in the fish host, as measured by variance to mean ratios, increased to a peak and then decreased significantly while the mean parasite burden remained constant. The effects of parasite burden on the survival of the stickleback host are discussed, as well as the validity of the use of changes in over-dispersion for demonstrating parasite-induced mortality.


Parasitology ◽  
1951 ◽  
Vol 41 (3-4) ◽  
pp. 156-161 ◽  
Author(s):  
H. A. Cole ◽  
R. E. Savage

1. Mytilicola intestindlis (Steuer) was found in 100% of mussels examined from Blyth, Northumberland. These mussels varied in length between 3·5 and 7·5 cm.2. The degree of infestation varied from two to fifty-nine parasites per mussel.3. There was an inverse relationship between the condition of mussels of the size group 5·5–5·9 cm. and both the mean number of parasites per mussel and the mean number of parasites over 1·5 mm. in length per mussel.4. The mean weight of flesh per mussel in the size group 5·5–5·9 cm. (shell length) was 3·206 g. from Blyth (parasitized) and 5·975 g. from Conway (not parasitized).5. It is concluded that the presence of Mytilicola is associated with a serious reduction of condition in infested mussels.


Parasitology ◽  
2002 ◽  
Vol 124 (6) ◽  
pp. 625-629 ◽  
Author(s):  
A. LEVSEN ◽  
P. J. JAKOBSEN

This paper describes the ability of the Asian fish nematode Camallanuscotti to carry out both heteroxeny, i.e. an indirect life-cycle using copepods as intermediate host, and monoxeny, i.e. direct infection and development in the definitive fish host. C. cotti occurs naturally in various freshwater teleosts in Asia. During the past decades it has been disseminated into closed or semi-closed aquaculture systems and aquaria around the world, mainly due to the ornamental fish trade. Under such conditions the species may frequently face a bottleneck situation with regard to the availability of copepods. It is known that C. cotti may reproduce and persist in copepod-free aquaria for several months. In order to investigate whether C. cotti has selected towards monoxeny in water systems lacking copepods, in contrast to the opposite selection pressure when copepods are present, 2 separate infection trials were run. It was shown that the parasite can infect the fish host both indirectly via copepods, and directly. However, C. cotti has significantly higher fitness, expressed as survival to maturity, when transmitted indirectly compared to the direct transmission mode. We suggest that the ability of aquarium populations of C. cotti to carry out a direct life-cycle is favoured by selection in order to avoid extinction whenever copepods are absent. It still remains unknown, however, whether the parasite shows the same characteristics in the wild.


Author(s):  
Cathryn L. Clarke ◽  
Annette Klussmann-Kolb

The parasitic copepod, Alimeda orientalis, is recorded from the gill of the sea hare, Dolabrifera brazieri (Gastropoda: Opisthobranchia: Anaspidea). Ten specimens of D. brazieri from a population on the coast of New South Wales, Australia were examined for the incidence of parasitism. Histological techniques and scanning electron microscopy were utilized to determine the feeding mode of A. orientalis and its effect on the host. Alimeda orientalis is a tissue feeder on the gill tissue, and damage caused by feeding and attachment is minimal.


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