| Summary: | 碩士 === 國立臺灣大學 === 動物學研究所 === 92 === The aim of this study were to investigate the parasitism of Anisakine nematode and Trichiurus lepturus. A total of 370 Trichiurus lepturus were obtained from commercial local fisheries in the coastal waters of E-Land (24-25°W,122-123°E)(N=185) and Tong-Kong (22-23°W,120-121°E)(N=185) between August 2003 and May 2004. Results of survey revealed 321 T. lepturus were infected. Larval anisakids representing four species of the gastrointestinal tract and abdominal cavity of T. lepturus were found:Anisakis simplex,Porrocaecum decipiens,Hysterothylacium aduncum and Raphidascaris trichiuri.The prevalence increased with the increased in the length of the fish, irrespective of the locality. In the T. lepturus most A. simplex and P. decipiens larvae were found in the posterior part of the body cavity, encapsulated on the mesenteries and coiled in flat spirals in clusters against the posterior extension of the stomach, indicating that T. lepturus could act as the transport or paratenic host for these nematodes. H. aduncum and R. trichiuri were present in the stomch and intestine, indicating that T. lepturus could act as the definitive host. There are significant differences in the prevalence of nematode for the length groups and months. The Mann-Whitney’s U test show significant differences in prevalence , mean intensity and abundance between the two zones.The relationship between fecundity and length for infected and uninfected fish was calculated as,㏒fecundity=0.035×㏒length—3.4772 and㏒fecundity=0.03×㏒length —2.9756, respectively. No significant difference between infected and uninfected fish was seen in either the fecundity-length data .Using the gene marker, the PCR-based RFLP approach for working out the method allowing four nematodes identification and differentiation. Digestion with Hinf I and Hhae I endonuclease allowed the identification of two different genotypes, belonging to A. pereffii and a recombinant genotypes of A. sximplex s.s. and A. pegreffii, describe the Taiwaneses coast as a hybrid zone for the two sibling species.
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