Temporal changes of the fish community in a seagrass bed after disappearance of vegetation caused by disturbance of the sea bottom and sediment deposition
Seto Inland Sea
To investigate the response of the fish community structure to a natural disturbance in their habitat, fish abundance, biomass and species composition were analysed in relation to temporal variability of environmental conditions in a seagrass Zostera marina bed. A total of 3024 fishes belonging to 46 taxa (22 families) were collected by quantitative sampling for 10 years from 2007 to 2016 in the Seto Inland Sea, south-western Japan. Seagrass shoot density decreased to less than 1/20 of its original density after disappearance of vegetation caused by heavy rain in the autumn of 2011 and the area did not recover for the next five years. In order to analyse temporal changes of fish community, the fishes were divided into three groups depending on their habitats or lifestyles: pelagic or migratory species (PM), sand or mud bottom-associated species (SM) and seagrass (Z. marina) – or substrate (rocky bottom including macrophytes) – associated species (ZS). Multiple regression analysis showed seagrass shoot density had the most significant effect on biomass of ZS among the three groups, with higher fish biomass under higher seagrass shoot density. Fish community composition changed after the disappearance of the seagrass vegetation coverage with an increase in abundance of SM during the five years of the post-disturbance period. Seagrass vegetation was concluded to affect temporal change of fish community structure through a stronger influence on fish species that are more dependent on seagrass beds as habitat.
This study was partially supported by the Global Environment Research Fund (J.S., grant number RF-0907and RF-1102) of the Ministry of the Environment, and Grant-in-Aid for Scientific Research (B) (J.S., grant number 24380107).
Journal of the Marine Biological Association of the United Kingdom
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Cambridge University Press
This article has been published in a revised form in Journal of the Marine Biological Association of the United Kingdom, https://doi.org/10.1017/S0025315419000845. This version is free to view and download for private research and study only. Not for re-distribution or re-use. © Marine Biological Association of the United Kingdom 2019.
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Graduate School of Integrated Sciences for Life