Larval development and ecology of intertidal thoracican barnacles and coral associated acrothoracican barnacles in Taiwan
Date Issued
2015
Date
2015
Author(s)
Tsai, Pei-Che
Abstract
Life cycle of barnacles is divided into two phases, with planktonic larval stage and adult sessile stage. Larval morphology and duration of larval development can affect the geographical distribution of barnacles. Examination of larval morphology and duration of larval development are important for further understanding of the larval ecology of intertidal species. The present study applied scanning electron microscope and optical microscopy techniques to examine the larval morphology of intertidal thoracican barnacles Tetraclita kuroshioensis, Tetraclita japonica formosana, Tetraclitella karandei, and the Acrothoracican barnacles Berndtia purpurea and B. utinomii. In the west Pacific, T. kuroshioensis has a wider range of distribution than T. japonica formosana which only present in Taiwan and Japan. Planktonic larval stage is the key period for dispersal with ocean current, which can affect the geographical distribution of species. In addition variations in tolerance to environmental stress, such as temperature and salinity between two species can result in different distribution pattern. Therefore, we compared the survival of larvae of T. kuroshioensis and T. japonica formosana at different temperatures (20, 25 and 30°C) and salinity (20, 25, 30 and 35 ‰). At 20°C, both larvae cannot metamorphosis to cyprids in all salinity treatment. At 25 and 30°C, naupliar duration is not significant different between two species. Therefore, variation in naupliar developmental duration between the two species did not affect their variation in geographical distribution. There are, however, greater percentage of stage VI larvae in T. kuroshioensis than T. japonica formosana at 25 and 30°C in all salinity situation. In addition, the number of metamorphosed cyprids is higher in T. kuroshioensis in most culture conditions. T. kuroshioensis has both high survival and metamorphosis rate, suggest they can survive in more strict condition, thus implying T. kuroshioensis has wider geographical distribution. This study provides 1) extensive database on larval morphology of Tetraclitidae barnacles of the West Pacific 2) first larval study of Acrothoraicican barnacles and 3) use larval ecology aspects to examine the factors affecting the geographical distribution of Tetraclita species in the west Pacific waters.
Subjects
Tetraclita kuroshioensis
Tetraclita japonica formosans
Tetraclitella karandei
Berndtia purpurea
B. utinomii
temperature
salinity
Type
thesis
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