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The broad aim of the work undertaken in this thesis was to increase understanding of how environmental changes in aquatic environments impact host-parasite interactions in the experimentally amenable copepod - three spined stickleback - Schistocephalus solidus model using controlled, laboratory experiments. In natural environments, animals are being exposed to a suite of anthropogenic stressors including temperature and heavy metal pollution. In this thesis the effects of temperature and heavy metals pollution are studied to determine the effect of these stressor on the growth development, survival and life cycle of both hosts and parasites. This thesis first investigated the effect of the temperature on the survival of infective free­ swimming stages (coracidia) of Schistocephalus solidus, and their subsequent development as procercoid larvae in copepods (first intermediate hosts). The survival of coracidia was temperature-dependent, with the longest survival times at I 0°C, and bei.....

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Water quality plays a major role in influencing the health of aquatic organisms and their interactions with parasites and disease. Pollutants that enter the aquatic environment, such as heavy metals, can potentially alter the relationships between hosts and their parasites and as a consequence influence the completion of parasites life cycles. Here, the influence of the heavy metal pollutant zinc on a life cycles stages of the cestode Schistocephalus solidus is investigated. In vitro culture of the parasite allowed the production of eggs, which were then incubated in a range of zinc concentrations (0.2 µg/L, 2 µg/L, 20 µg/L and 200 µg/L). The effect of zinc on S. solidus egg viability, on the survival of emerging free-living, motile infective stages (coracidia) and on the subsequent development or growth of the parasite in copepod hosts was then quantified. The development and hatching success of S. solidus eggs developed normally in elevated zinc concentrations up to 0.2 µg/L but.....

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Anabas testudineus or locally known as 'puyu' is a freshwater fish species grown in Southeast Asian  countries. This study was carried out from March - December 2010 at Aquaculture Experimental  Station of Universiti Putra Malaysia. This fish is also known as a species that has a low survival  rate during its early life stage and fry. Its Seed production and stock assessment are  still   poorly  understood  due  the  high  mortality  at  first  stage  of development. In the rearing  aspect, high food convertion ratio has been recorded when this fish is reared in hapas and earth  ponds using homemade food. The objectives of this study were to induce breed climbing perch (Anabas testudineus) using a commercial hormone preparation (Luteinizing Hormone Releasing  Hormone  analogue  (LHRHa),  to  observe  and  record  the modetermine its the effectiveness of LHRHa as an agent to induce maturation and ovulation of A. testudineus with the intensity level of 2, .....

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