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Accession number;07A0232963
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| Title;Relict estuarine ecosystem isolated from the continental coastal waters |
| Author;
TANAKA MASARU
(Kyoto Univ., JPN)
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Journal Title;Aquabiology
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Journal Code:S0220B
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ISSN:0285-4376
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VOL.29;NO.1;PAGE.3-9(2007)
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| Figure&Table&Reference; |
| Pub. Country;Japan |
| Language;Japanese |
| Abstract;Estuarine ecosystem was surveyed for more than 25 years in the largest Chikugo river estuary where is acting as the most important habitat for continental relict species including 7 fishes. One of the interesting results was that the Ariake temperate bass is a hybrid population occurred between the Japanese temperate bass Lateolabrax japonicus and Chinese temperate bass Lateolabrax sp., even though both are separately distributed at the present time. It was speculated that hybridization happened during the last ice age when the Chinese coastal line was very close to the Kyushu coastal waters due to the sea level down of about 150m. Mysteriously enough, such a unique population have well adapted only to the bottom of the Ariake Sea. Relict fish species endemic to the Ariake Sea spawn in various grounds including sea, estuary and river. However those juveniles elapsed more than one to two months since hatching aggregated to almost freshwater and/or very low salinity brackish waters. It could be explained that development of low salinity adaptation and of large biomass by aggregation of very large copepod Sinocalanus sinensis which is also a continental relict species. Stomach content analyses clearly demonstrated the relict fish juveniles were highly dependent on the relict copepod. Finally the authors found the relict copepod ingested detritus which is the most abundant around the lowest salinity area. Then we hypothesized "Continental relict estuarine ecosystem" which is composed of a strong combination of highly turbid brackish water, relict prey and relict predators. The ecosystem was speculated to be isolated from the continental coastal waters during the end of the last ice age. (author abst.) |
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