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Levantamento preliminar dos nemátodes anisaquídeos presentes no Gorz, Pagellus bogaraveo, (Br nnich, 1768), no estado selvagem na Região Autònoma da Madeira
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Abstract(s)
No presente trabalho foram analisados 77 exemplares de goraz# Pagellus bogaraveo
(Brunnich, 1768) (Teleostei: Sparidae) capturados na águas do Arquipélago da Madeira. As
amostragens desta espécie piscícola decorreram de Novembro de 1999 a Julho de 2000.
Nesse período foram recolhidos 94 larvas de nemátodes (Nematoda: Ascaridida: Anisakidae).
Após o estudo morfológico, as larvas encontradas nas vísceras dos hospedeiros,
foram identificadas como pertencendo ao género Anisakis e Hysterothylacium. Com base nas
características morfológicas foram identificados dois tipos de larvas de Anisakis (L3), as
larvas tipo I e tipo II (sensu Berland, 1961) que correspondem respectivamente a Anisakis
simpiex s.l. e Anisakis physeterís ou à espécie A. brevispicuiata. As larvas de
Hysterothylacium foram classificadas em larvas L3 e Ude acordo com a forma da cauda. A
identificação das espécies não foi conclusiva uma vez que seria necessária a presença de
adultos bem como a realização de estudos genéticos para uma correcta identificação das
mesmas. A prevalência foi bastante elevada (81,3 a 96,3%) em todas as classes de
comprimento, verificando-se um ligeiro aumento à medida que o comprimento do peixe
aumenta. Por outro lado, a intensidade apresentou valores relativamente baixos registandose
o valor mais elevado na classe de comprimento 25-35 cm (valor médio de 5,2). Apesar
dos valores de prevalência serem elevados, os valores de intensidade são baixos o que
demonstra que o parasitas se apresentam dispersos pelos hospedeiros. O que é confirmado
pelos valores do índice de discrepância (D= 0,534) e pelo valor de k (k= 1,26).
Estes resultados permitem concluir que não se registam efeitos nocivos causados
pelos parasitas, no que diz respeito à condição física dos hospedeiros.
Several larval nematodes (Nematoda: Ascaridida: Anisakidae) were recovered from the víscera of 77 blackspot seabream Pagellus bogaraveo (Brunnich, 1768) (Teleostei: Sparidae) from November 1999 to July 2000. After morphplogical study the 94 larval nematodes found in víscera of this fish host were assigned to the genera Anisakís and Hysterothylacium. The larval stages of Anisakis (stage L3) were further identified as type I and type II (sensu Berland, 1961) according to the site and shape of the ventricule and shape of the tail. As specific species identification is only possible after genetic or molecular characterization the Anisakís L3 larvae were named as Anisakis sp. L3. Some of these larvae were sent to Rome and after PCR-RFLPs of the ribossomal DNA they were identified as Anisakís simpiex s.s. and A. pegreffii. The larval stages of Hysterothylacium were characterized as L3 and U larval stages according to tail shape. Species identification at this point was inconclusive as here too detailed genetic studies and presence of adult males was necessary. Prevalence of nematodes in the blackspot seabream was quite high (up to 96,3%) in ali the length classes examined. There was an increasing tendency of prevalence with length although not significant. Intensity with nematodes was low, being the highest value 5,2 for the length class 25-35 cm. Although prevalence values were high, intensity was low meaning that the parasites seemed to be relative dispersed throughout several hosts. This was confirmed by the values D and K obtained, respectively 0,534 and 1,26.
Several larval nematodes (Nematoda: Ascaridida: Anisakidae) were recovered from the víscera of 77 blackspot seabream Pagellus bogaraveo (Brunnich, 1768) (Teleostei: Sparidae) from November 1999 to July 2000. After morphplogical study the 94 larval nematodes found in víscera of this fish host were assigned to the genera Anisakís and Hysterothylacium. The larval stages of Anisakis (stage L3) were further identified as type I and type II (sensu Berland, 1961) according to the site and shape of the ventricule and shape of the tail. As specific species identification is only possible after genetic or molecular characterization the Anisakís L3 larvae were named as Anisakis sp. L3. Some of these larvae were sent to Rome and after PCR-RFLPs of the ribossomal DNA they were identified as Anisakís simpiex s.s. and A. pegreffii. The larval stages of Hysterothylacium were characterized as L3 and U larval stages according to tail shape. Species identification at this point was inconclusive as here too detailed genetic studies and presence of adult males was necessary. Prevalence of nematodes in the blackspot seabream was quite high (up to 96,3%) in ali the length classes examined. There was an increasing tendency of prevalence with length although not significant. Intensity with nematodes was low, being the highest value 5,2 for the length class 25-35 cm. Although prevalence values were high, intensity was low meaning that the parasites seemed to be relative dispersed throughout several hosts. This was confirmed by the values D and K obtained, respectively 0,534 and 1,26.
Description
Dissertação de mest. em Aquacultura, Faculdade de Ciências do Mar e do Ambiente, Univ. do Algarve, 2001