7 research outputs found
Metazoários parasitos de seis espécies de peixes do Reservatório de Lajes, Estado do Rio de Janeiro, Brasil Metazoan parasites of six fishes species from Lajes Reservoir in the State of Rio de Janeiro, Brazil
Entre abril de 2002 e julho de 2003, foram necropsiados 231 espécimes de peixes: 39 Astyanax bimaculatus (Linnaeus, 1758), 79 A. fasciatus (Cuvier, 1819), 23 Hypostomus affinis (Steindachner, 1877), 26 Hoplias malabaricus (Bloch, 1794), 30 Loricariichthys castaneus (Castelnau, 1855) e 34 Trachelyopterus striatulus (Steindachner, 1876) provenientes do Reservatório de Lajes (22º42' - 22º50'S, 43º53' 44º05'O), Estado do Rio de Janeiro, Brasil, para estudo das suas comunidades parasitárias. A maioria dos espécimes de H. affinis (95,6%) e H. malabaricus (84,6%) estavam parasitados por pelo menos uma espécie de metazoário. Em A. bimaculatus, A. fasciatus, L. castaneus e T. striatulus 41%, 39,2%, 56,7% e 14,7% dos espécimes estavam parasitados, respectivamente. Foram coletadas oito diferentes espécies de metazoários parasitos: 2 em A. bimaculatus, 3 em A. fasciatus, 3 em H. affinis, 4 em H. malabaricus, 4 em L. castaneus e 1 em T. striatulus. As comunidades de metazoários parasitos das seis espécies de peixes estudadas apresentaram tÃpico padrão de distribuição agregada. Foram observados dois casos de correlação negativa entre a abundância e a prevalência parasitárias e o comprimento total dos hospedeiros. A comunidade parasitária de L. castaneus apresentou os maiores valores de intensidade média, Ãndice de dispersão e diversidade. As comunidades parasitárias dos peixes estudados apresentaram escassez de correlação entre a abundância, riqueza parasitária e diversidade com o comprimento total dos hospedeiros. Os baixos valores de riqueza e diversidade das comuni-dades parasitárias podem ser atribuÃdos as caracterÃsticas oligotróficas do Reservatório de Lajes.From April 2002 to July 2003, 231 freshwater fishes from Lajes Reservoir in the State of Rio de Janeiro, Brazil (22º42' - 22º50'S, 43º53' - 44º05'W) were necropsied to study their community metazoan parasites: 39 Astyanax bimaculatus (Linnaeus, 1758), 79 A. fasciatus (Cuvier, 1819), 23 Hypostomus affinis (Steindachner, 1877), 26 Hoplias malabaricus (Bloch, 1794), 30 Loricariichthys castaneus (Castelnau, 1855) and 34 Trachelyopterus striatulus (Steindachner, 1876). The majority of specimens of H. affinis (95.6%) and H. malabaricus (84.6%) was parasitized by one or more metazoan species. In A. bimaculatus, A. fasciatus, L. castaneus and T. striatulus 41%, 39.2%, 56.7 and 14.7% of specimens were parasitized, respectively. Eight different metazoan parasites species were collected: 2 in A. bimaculatus, 3 in A. fasciatus, 3 in H. affinis, 4 in H. malabaricus, 4 in L. castaneus and 1 in T. striatulus. The parasites of the six host species showed the typical aggregated pattern of distribution. Two cases of negative correlation between host's total length and prevalence and parasite abundance were detected. The parasite community of L. castaneus showed the higher values of mean intensity, index of dispersion and higher values of diversity. The parasite communities of the studied fishes showed scarcity of significant correlations of parasitic abundance, species richness and diversity with the size of the host. The low species richness and diversity of parasite communities could be originated by the oligotrophic characteristics of the Lajes Reservoir
A new species of Anoplodiscus (Monogenea: Anoplodiscidae) parasitic on Pagrus pagrus (Osteichthyes: Sparidae) from the coastal zone of the State of Rio de Janeiro, Brazil
A new species of Anoplodiscus (Monogenea, Anoplodiscidae), parasitic on gills of the red porgy, Pagrus pagrus, from the coastal zone of the State of Rio de Janeiro, Brazil, is described and illustrated. The new species can be differentiated from the other species of this genus by the shape of the accessory piece of the copulatory complex, and the length of the vagina. This is the first record of a species of Anoplodiscus in the Neotropical region
A new species of Anoplodiscus (Monogenea: Anoplodiscidae) parasitic on Pagrus pagrus (Osteichthyes: Sparidae) from the coastal zone of the State of Rio de Janeiro, Brazil
A new species of Anoplodiscus  (Monogenea, Anoplodiscidae),
parasitic on gills of the red porgy, Pagrus pagrus  , from the
coastal zone of the State of Rio de Janeiro, Brazil, is described and
illustrated. The new species can be differentiated from the other
species of this genus by the shape of the accessory piece of the
copulatory complex, and the length of the vagina. This is the first
record of a species of Anoplodiscus in the Neotropical region
Community ecology of the metazoan parasites of pink Cusk-eel, Genypterus brasiliensis (Osteichthyes: Ophidiidae), from the coastal zone of the State of Rio de Janeiro, Brazil
Fifty-five specimens of pink cusk-eel, Genypterus brasiliensis Â
Regan, 1903 (Osteichthyes: Ophidiidae) collected from the coastal zone
of the State of Rio de Janeiro, Brazil (approx. 21-23°S,
41-45°W), from September 2000 to January 2001, were necropsied to
study their parasites. All fish were parasitized by one or more
metazoan. Fourteen species of parasites were collected. G. brasiliensis
is a new host record for nine parasite species. The larval stages of
cestodes and the nematodes were the majority of the parasite specimens
collected, with 38.4% and 36.5%, respectively. Cucullanus genypteri
 was the dominant species with highest prevalence and/or
abundance. The parasites of G. brasiliensis showed the typical
overdispersed pattern of distribution. Six parasite species showed
correlation between the host's total body length and prevalence and
abundance. Host sex did not influence prevalence and parasite abundance
of any parasite species. The mean diversity in the infracommunities of
G. brasiliensis was H= 0.364 ± 0.103, with correlation with the
host's total length and without differences in relation to sex of the
host. One pair of adult endoparasites ( C. genypteri and A.
brasiliensis ) showed positive covariations between their abundances.
Negative association or covariation was not found. Differences between
the qualitative and quantitative aspects of the parasite community of
G. brasiliensis from Rio de Janeiro and Argentina suggest the existence
of two population stocks of pink cusk-eel in the South America Atlantic
Ocean