Browsing by Author "Takaomi, Arai"

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    Influence Of Growth On Fatty Acid Composition Of The Moon Wrasse Thalassoma Lunare Collected In Coral Reef Habitats Of The Malaysian South China Sea
    (Tropical Ecology, 2016-12) Razikin, Amalina; Zainudin, Bachok; Takaomi, Arai
    The composition of fatty acids in fishes can serve as trophic biomarkers in the analysis of marine food webs because fatty acids can be traced as essential dietary components to higher trophic levels; however, information on tropical coral fishes is scarce. In order to understand the feeding ecology of coral reef fish, fatty acid composition and levels were examined in the moon wrasse Thalassoma lunare collected in the Malaysian South China Sea. Fatty acid composition was predominantly saturated fatty acids (SAFA) (62.5 %), followed by monounsaturated fatty acids (MUFA) (33.8 %) and polyunsaturated fatty acids (PUFA) (3.7 %). The most abundant fatty acids in SAFA, MUFA and PUFA were palmitic acid (C16:0), oleic acid (C18:1ω9c) and elaidic acid (C18:1ω9t) and linolenic acid (C18:3n3) and EPA (C20:5n3), respectively. Fatty acid concentrations, especially in SAFA and MUFA, changed with fish growth, although PUFA did not change in fish growth. Such differences might be caused by differences in the diet of the fish accompanying the growth.
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    Repeated Vertical Movements Of Mature Anguillid Eels In A Lake
    (Marine and Freshwater Research, 2016) Yuuki Y., Watanabe; Takaomi, Arai; Daniel, Limbong; Yunober, Mberato; Nobuyuki, Miyazaki
    Reproductive migration is a critical phase in the life history of anguillid eels. Nevertheless, fine-scale behaviours of migrating eels remain unknown, primarily due to the difficulty in attaching high-resolution recording devices to, and recovering them from, these small-sized teleosts. We attached a small accelerometer with time-scheduled release system to mature Anguilla celebesensis and A. marmorata in Lake Poso, Indonesia, during the pre-migration period. The eels repeated up-and-down movements in the water column (maximum depth, 77m), with slower, less active descents at shallower pitch angles, followed by faster, more active ascents at steeper pitch angles. The asymmetric diving pattern indicates negative buoyancy of the eels, which was confirmed by the measurements of body densities. The repeated diving is unlikely to represent foraging or thermoregulation because mature eels are thought to fast and water temperature changed little with depth. We suggest that the repeated diving is a result of the eels' internal motivation for continuous swimming in preparation for oceanic migration, and is possibly energetically more efficient than if they keep swimming at a certain depth. The swimming energetics of eels in nature might be more complicated than previously thought because of the effect of vertical movements and non-neutral buoyancy