ISSN : 2287-8327
Background: There have been many studies on the growth conditions of Zostera marina and Zostera japonica, but few studies have examined how spatial and temporal factors affect growth in established seagrass beds or the distribution range and shoot density. This study aims to clarify the factors that determine the temporal and spatial distribution of Zostera marina and Zostera japonica in the Seto Inland Sea east of Yamaguchi Prefecture. Methods: The study site is in Hiroshima Bay of the Seto Inland Sea, along the east coast of Yamaguchi Prefecture, Japan. We monitored by diving observation to confirm shoot density, presence or absence of both species and observed water temperature, salinity by sensor in study sites. Results: The frequency of occurrence of Zostera marinawas high in all seasons, even in water depths of D.L. + 1 to −5 m (80 ± 34% to 89 ± 19%; mean ± standard deviation), but lower (as low as 43 ± 34%) near the breakwall, where datum level was 1 to 2 m, and it was further reduced in datum level −5 m and deeper. The frequency of occurrence of Zostera japonica was highest in water with a datum level of +1 to 0 m. However, in datum level of 0 m or deeper, it became lower as the water depth became deeper. Datum level +1 m to 0 m was an optimal water depth for both species. The frequency of occurrence and the shoot density of both species showed no negative correlation. In 2011, the daily mean water temperature was 10 °C or less on more days than in other years and the feeding damage by S. fuscescens in the study sites caused damage at the tips. Conclusions: We considered that the relationship between these species at the optimal water depth was not competitive, but due to differences in spatial distribution, Zostera marina and Zostera japonica do not influence each other due to temperature conditions and feeding damage and other environmental conditions. Zostera japonica required light intensity than Zostera marina, and the water depth played an important role in the distribution of both species.
Abe, M., Hashimoto, N., Kurashima, A., & Maegawa, M. (2004). Structure and seasonal change of the Zostera marina population on the coast of Matsunase, Mie Prefecture, central Japan. Nippon Suisan Gakkai, 70(4), 523–529.
Abe, M., Yokota, K., Kurashima, A., & Maegawa, M. (2009). Temperature characteristics in seed germination and growth of Zostera japonica Ascherson & Graebner from Ago Bay, Mie Prefecture, central Japan. Fisheries Science, 75, 921–927.
Aioi, K. (1998). On the red list species of Japanese seagrasses. Aquabiology, 20(1), 7–12.
Aioi, K., & Nakaoka, M. (2003). The seagrass of Japan. In E. P. Green & F. T. Short (Eds.), World Atlas of Seagrasses (pp. 185–192). Berkley: University of California Press.
Arasaki, S. (1950a). Studies on the ecology Zostera marina and Z. nana (1). Nihon Suisan Gakkai, 15(10), 567–572.
Arasaki, S. (1950b). Studies on the ecology Zostera marina and Z. nana. Nihon Suisan Gakkai, 16(2), 70–76.
Biodiversity Center of Japan (2008) 7th Natural Environment Basic Research Shallow water ecosystem research (Seagrass bed research) Report (pp. 354–357)
Dennison, W. C., & Alberte, R. C. (1985). Role of daily light period in the depth distribution of Zostera marina (eelgrass). Marine Ecology Progress Series, 25, 51–61.
Duarte, C. M. (1991). Seagrass depth limits. Aquatic Botany, 40, 363–377.
Greve, T. M., & Krausen-Jensen, D. (2005). Predictive modeling of eelgrass (Zostera marina) depth limit. Marine Biology, 146, 849–858.
Harrison, P. G. (1982). Seasonal and year-to-year variations in mixed intertidal populations of Zostera japonica Aschers. & Graebn. and Ruppia maritima L. S. L. Aquatic Botany, 14, 357–371.
Kawamata, S., & Masegawa, M. (2006). Effects of waves and temperature on feeding by the Rabbitfish Siganus Fsuscescens on Kelps Eisenia Bicyclis and Ecklonia cava. Fisheries Engineering, 46(1), 69–79.
Kawanishi, K. (1999). Characteristics of Water Exchange and Current Structures in North Area of Hiroshima Bay. Proceedings of Coastal Engineering, 46, 1041–1045.
Kawasaki, Y., Iituka, T., Goto, H., Terawaki, T., Shimo, S. (1986) Effects of temperature on Zostera marina L. 1. Seed Germination and Seedling Development, Central Research Institute of Electric Power Industry, Rep. No. 485028
Kendrick, G. A., Aylward, M. T., Hegge, B. J., Cambridge, M. L., Hillman, K., Wyllie, A., & Lord, D. A. (2002). Changes in seagrass coverage in Cockburn Sound, Western Australia between 1967 and 1999. Aquatic Botany, 73, 75–87.
Kikuchi, T. (1980). Faunal relationships in temperate seagrass beds. In R. C. Phillips & C. P. McRoy (Eds.), Holland book of Seagrass Biology (An Ecosystem Perspective, pp. 153–172). New York and London: Garland STPM Press.
Kishima, J., Harada, S., & Sakurai, R. (2011). Suitable water temperature for seed storage of Zostera japonica for subtropical seagrass bed restoration. Ecological Engineering, 37, 1416–1419.
Mach, M.E., Wyllie-Echeverria S., Ward J. R. (2010) Distribution and potential effects of a non-native seagrass in Washington State Zostera japonica Workshop, Friday Harbor Laboratories, San Juan Island, WA, (pp. 14–16)
Mach, M. E., Wyllie-Echeverria, S., & Chan, K. M. A. (2014). Ecological effect of a nonnative seagrass spreading in the Northeast Pacific: a review of Zostera japonica. Ocean & Coastal Management, 102, 375–382.
Masuda, M., Tsunoda, T., Hayashi, Y., Nishio, S., Mizui, H., Horiuchi, S., & Nakayama, Y. (2000). Decline of afforested Ecklonia Cava community by grazing of Herbivorous fish Siganus fuscescens. Fisheries Engineering, 37(2), 135–142.
Morita, T., Kokubu, H., Miyamatsu, A., Fujii, M., Kurashima, A., & Maegawa, M. (2010). The effect of water temperature in the sediment and the desiccation period on the growth and survival of transplant seagrass Zostera japonica shoots in Mesocosm tank culture. Aquaculture Science, 58(2), 261–267.
Omori, Y. (2000). Japanese seagrasses. Distirbution and morphology. Aquabiology, 22(6), 524–532.
Orth, R. C. (1977). Effect of nutrient enrichment on growth of the eelgrass Zostera marina in the Chesapeake Bay Virginia USA. Marine Biology, 44, 187–194.
Orth, R. J., Heck, K. L. H., Jr., & Montfrans, J. V. (1984). Faunal communities in seagrass beds: a review of the influence of plant structure and prey characteristics on predator–prey relationships. Estuaries, 7(4A), 339–350.
Pollard, D. A. (1984). A review of ecological studies on seagrass–fish communities, with particular reference to recent studies in Australia. Aquatic Botany, 18, 3–42.
Shafer, D. J., Kaldy, J. E., Sherman, T. D., & Marko, K. M. (2011). Effects of salinity on photosynthesis and respiration of the seagrass Zostera japonica : a comparison of two established populations in North America. Aquatic Botany, 95, 214–220.
Shafer, D. J., Kaldy, J. E., & Gaeckle, J. L. (2014). Science and management of the introduced seagrass Zostera japonica in North America. Environmental Management, 53, 147–162.
Shimaya, M., Sato, K., Nakase, K., Kuwae, T., & Nakamura, Y. (2004). A study on physical environment suitable for Zostera Japonica growth. Annual Journal of Coastal Engineering, 51, 1031–1035.
Sugimoto, K., Asaoka, Y., Matsunami, D., Terawaki, T., Okada, M. (2012). Extinction of eelgrass off the coast of Iwakuni, Seto Inland Sea in decline period, Annual Journal of Japan Society on Water Environment, 46, 236.
Sugimoto, K., Hiraoka, K., Tamaki, H., Terawaki, T., Okada., M., (2003) Effects of Breakwater Construction on the Distribution of Transplanted Eelgrass Beds (Zostera marina L.), Proceedings of the 6th International EMECS Conference, (pp. 295–302)
Sugimoto, K., Hiraoka, K., Ohta, S., Niimura, Y., Terawaki, T., & Okada, M. (2007). Effects of ulvoid (Ulva spp.) accumulation on the structure and function of eelgrass (Zostera marina L.) bed. Marine Pollution Bulletin, 54, 1582–1585.
Sugimoto, K., Hiraoka, K., Tanida, K., Terawaki, T., & Okada, M. (2008). Restration of eelgrass (Zostera marina L.) Beds by Filling up Borrow Pits with Natural Sediment. Journal of Japan Society on Water Environment, 31(4), 217–221.
Tiina, S., Morten, F. P., & Christoffer, B. (2014). Population specific salinity tolerance in eelgrass (Zostera marina). Journal of Experimental Marine Biology and Ecology, 461, 425–429.