Submitted by Celso Magalhaes (celsomagalhaes@ufrrj.br) on 2017-07-06T13:19:39Z No. of bitstreams: 1 2015 - Naraiana Lopes Taborda.pdf: 2569264 bytes, checksum: dd82638f045c3152324e7f8757f3a526 (MD5) / Made available in DSpace on 2017-07-06T13:19:39Z (GMT). No. of bitstreams: 1 2015 - Naraiana Lopes Taborda.pdf: 2569264 bytes, checksum: dd82638f045c3152324e7f8757f3a526 (MD5) Previous issue date: 2015-12-22 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico - CNPq / The current work aimed to increase the knowledge of biodiversity of parasite of fishes, unknown to some groups. In Chapter 1 the aim was described the new species ergasilid copepod Ergasilus von Nordmann, 1832, found on the gills of two cichlid fishes, Geophagus argyrostictus Kullander, 1991 (type host) and G. altifrons Heckel, 1840, caught in the Xingu River around Altamira, State of Par?, Brazil. The new species is the first record of genus Ergasilus found on fishes G. argyrostictus e G. altifrons. In Chapter 2, species of Encotyllabe Perciformes host were analyzed by molecular study, with analysis of cytochrome c oxidase I gene (COI) and morphological study. These data identify two new species, a parasite of Pagrus pagrus (Sparidae) and other of Orthopristis ruber (Haemulidae), and addition of the sequence mitochondrial DNA to E. souzalimae Carvalho e Luque, 2012. / O presente trabalho teve como objetivo ampliar os conhecimentos sobre a biodiversidade de parasitos de peixes, visto o escasso conhecimento para alguns grupos. No cap?tulo 1 objetivamos a descri??o de uma nova esp?cie do cop?pode parasito Ergasilus von Nordmann, 1832, encontrado parasitando as br?nquias de duas esp?cies de cicl?deos, Geophagus argyrostictus Kullander, 1991 (esp?cie tipo) e G. altifrons Heckel, 1840, capturados no Rio Xingu em torno de Altamira, Estado do Par?, Brasil. A nova esp?cie ? o primeiro registro do g?nero Ergasilus encontrado em peixes G. argyrostictus e G. altifrons. No cap?tulo 2, esp?cies de Encotyllabe encontradas em hospedeiros Perciformes foram analisadas atrav?s do estudo molecular, com an?lise do gene citocromo c oxidase I (COI) e morfol?gico. Estes dados identificam duas esp?cies novas, uma parasita de Pagrus pagrus (Sparidae) e outra de Orthopristis ruber (Haemulidae) e a adi??o da sequ?ncia de DNA mitocondrial para E. souzalimae Carvalho e Luque, 2012.

M.Sc. (Zoology) / A literature survey revealed gaps in the knowledge on Ergasilus in Africa. This studied aimed to elucidate on some of these matters. Ergasilus sarsi was collected from Lamprichthys tanganicanus during an expedition to Lake Tanganyika in March 2010. The gills of the fish were removed and preserved for further studies. Preserved specimens were studied with dissection- and light microscopy. Some specimens were also studied with a scanning electron microscope (SEM). For light microscopy the specimens were sectioned and then stained with AZAN and H&E. A total of 32 Lamprichthys tanganicanus were collected and studied for ergasilids. The prevalence was 86.40%, the mean intensity 7.56 and the mean abundance 6.38. A total of 204 parasites were collected and only 27 hosts were infected. The highest intensity was 29 parasites. Pearson’s Chi-squared test was used to compare attachment preferences of Ergasilus sarsi. The parasite exhibited site selection but not host specificity. It was noticed that E. sarsi mostly attach to the tip of the gill filament of the second gill arch. The second gill arch receives the largest portion of water flow supporting distribution of newly hatch ergasilid nauplius. There was no significant preference for the dorsal, medial and ventral attachment sites (p-value = 0.000542). However, significant preference between distal, central and proximal regions (p-value = 1.19) was observed. Fryer (1965) observed that the pathology caused by ergasilids is related to their attachment position on the host. Ergasilids display variation regarding morphology of their second antennae. Some have spines and others elongated antennae that wraps around the entire gill filament. This study shows that Ergasilus sarsi (with no spines on the second antennae) wraps around the gill filament and cause considerable damage to the host. The entire gill filament structure changed due to lamellar fusion and proliferation of mucous – and epithelial cells. Comparison of an infected gill to a healthy gill revealed differences. The compression caused by the second antennae caused some blood vessels to rupture resulting in haemorrhage. The swimming legs of the parasite also cause considerable damage by scraping gill tissue off the host and pushing it towards the mouth parts of the parasite. Mucous cells, gill epithelium and blood cells were observed in the vicinity of the mouth and in the intestine of the parasite. An increase in the number of Rodlet cells and mast cells were also observed on the gills in close proximity to the parasite. Increase in the number of these cells clearly indicate an inflammatory response. This is the first record of Ergasilus sarsi on Lamprichthys tanganicanus. This study also provides the first detailed description of the pathology caused by Ergasilus sarsi as well as the attachment distribution of this parasite.

D.Phil. / Please refer to full text to view abstract

Ergasilus sieboldi has been reported from a number of trout fisheries in England and Wales. The population dynamics of this parasitic copepod in Rutland Water, a large reservoir in Central England was studied from 2003 to 2005. A combination of angler and net caught fish were examined to record numbers of adult females and egg production throughout each year. The parasite overwintered in large numbers on trout and commenced egg production in April which then continued until October/November. The prevalence of infection and the abundance of the parasite were very high in overwintered rainbow trout but these parameters then decreased in March as large numbers of uninfected fish were stocked into the reservoir. The parasite population then increased until October. Infection levels in 2004 and 2005 were significantly lower than in 2003. Infections of cage-held rainbow trout showed that E.sieboldi could become ovigerous within two weeks of attachment to trout in July and August. New infections occurred from June until November. Several species of coarse fish examined were also shown to be infected by the parasite. Cage trials showed that triploid rainbow trout were infected by significantly higher numbers of the parasite than diploid rainbow, brown trout or “blue” rainbow trout. Observations of infected fish in experimental tanks showed that overwintering parasites were stimulated to commence oviposition by increasing water temperatures. Photoperiod had no noticeable effect on the parasite. Egg viability and rate of development was studied using tank held infected fish and in vitro incubation techniques. Viability of eggs in sacs detached from the adult parasite was greater than those remaining attached. The rate of egg development was modelled and was shown to be predicted by temperature. Development of eggs was estimated to commence at 3.6ºC. Eggs developed more rapidly at higher temperatures and at peak production, inter-clutch interval was between 0 and 0.5 days. Egg production models estimated that an overwintered parasite could produce up to 19 clutches of eggs between April and October under normal temperature regimes measured at the reservoir. Ovarian development during the winter was confirmed using classifications of ovary size and shape based on parameters measured using image analysis techniques. The life span of E.sieboldi was estimated at 10-12 months. Nauplii culturing techniques were compared, and nauplii to stage V were successfully developed. Nauplii hatched from the eggs of adult parasites occurring in the spring were larger and conditioned to develop at lower temperatures than those hatched later in the year. Nauplii were fed on 4 different types of algae held in monocultures but development occurred only in algal polycultures. A comparison was made of nauplii feeding preferences and development with algae recorded in Rutland Water in 2003 and 2005 but no correlations were found. Fish stock assessment was carried out using models of angler catch, effort and stocking figures from the fishery. Parasite numbers on the overwintered fish were estimated at 12 million parasites in April 2003, 8.3 million in April 2004 and 1.2 million in April 2005. Stock assessments suggested a reduction in number of overwintering trout and effects of stocking policy to be at least partially responsible for the decline in the parasite population. The results of this study formed a management strategy for the operation of the trout fishery.