Mapping is a Key for Sustainable Development of Coastal Waters: Examples of Seagrass Beds and Aquaculture Facilities in Japan with Use of ALOS Images

Komatsu, Toshimitsu; Sagawa, T.; Sawayama, Shuhei; Tanoue, Hideaki; Mohri, Akihiko; Sakanishi, Yoshihiko

doi:10.5772/26613

Cited by 10 publications

(9 citation statements)

References 16 publications

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“…Chlorophyll a (chl-a) concentrations have been reported to be high in the bay during spring (JAXA, 2004), which has attracted buoy-and-rope type scallop and oyster culture facilities (Komatsu et al, 2012). Considering its economic and environmental importance, the Ofunato Bay has received much attention, and there has been continuous monitoring of its seawater quality parameters by organizations such as the Iwate Fisheries Technology Center and Japan Aerospace Exploration Agency (JAXA).…”

Section: Introductionmentioning

confidence: 99%

Basin-scale seasonal changes in marine free-living bacterioplankton community in the Ofunato Bay

Reza

Kobiyama

Yamada

et al. 2018

Gene

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The Ofunato Bay in the northeastern Pacific Ocean area of Japan possesses the highest biodiversity of marine organisms in the world and has attracted much attention due to its economic and environmental importance. We report here a shotgun metagenomic analysis of the year-round variation in free-living bacterioplankton collected across the entire length of the bay. Phylogenetic differences among spring, summer, autumn and winter bacterioplankton suggested that members of Proteobacteria tended to decrease at high water temperatures and increase at low temperatures. It was revealed that Candidatus Pelagibacter varied seasonally, reaching as much as 60% of all sequences at the genus level in the surface waters during winter. This increase was more evident in the deeper waters, where they reached up to 75%. The relative abundance of Planktomarina also rose during winter and fell during summer. A significant component of the winter bacterioplankton community was Archaea (mainly represented by Nitrosopumilus), as their relative abundance was very low during spring and summer but high during winter. In contrast, Actinobacteria and Cyanobacteria appeared to be higher in abundance during high-temperature periods. It was also revealed that Bacteroidetes constituted a significant component of the summer bacterioplankton community, being the second largest bacterial phylum detected in the Ofunato Bay. Its members, notably Polaribacter and Flavobacterium, were found to be high in abundance during spring and summer, particularly in the surface waters. Principal component analysis and hierarchal clustering analyses showed that the bacterial communities in the Ofunato Bay changed seasonally, likely caused by the levels of organic matter, which would be deeply mixed with surface runoff in the winter.

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Section: Introductionmentioning

confidence: 99%

Basin-scale seasonal changes in marine free-living bacterioplankton community in the Ofunato Bay

Reza

Kobiyama

Yamada

et al. 2018

Gene

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“…However, over the years, coastal aquaculture development has degraded some coastal ecosystems ( Delgado et al, 1999 ; Huitric, Folke & Kautsky, 2002 ; Ilman et al, 2016 ). Therefore, the conservation of coastal ecosystems as well as the efficient management of aquaculture is crucial for the sustainable development of coastal waters ( Komatsu et al, 2012 ).…”

Section: Introductionmentioning

confidence: 99%

“…Aquaculture is therefore managed by the FCAs following a “bottom-up” structure in Japan ( Komatsu & Aoki, 2020 ). Nevertheless, in general, FCAs do not know the exact locations of aquaculture facilities, as it is difficult to gather information about locations of aquaculture facilities solely from field surveys when they are numerous ( Komatsu et al, 2012 ; Murata, Komatsu & Yonezawa, 2019 ). Since the sustainable use of coastal waters is necessary for Sustainable Development Goal 14 saying “Conserve and sustainably use the ocean, sea and marine resources for sustainable development” accurately mapping aquaculture facilities by type in a demarcated fishery right area contributes to SDG14 through their management.…”

Section: Introductionmentioning

confidence: 99%

“…Since bottom depths were changed by co-seismic land subsidence and post-seismic uplift after the tsunami ( Geospatial Information Authority of Japan, 2020 ), the lower depth limits of seagrass meadows limited by light availability enough for survivals of seagrasses ( Duarte, 1991 ; Komatsu & Tatsukawa, 1998 ; Sakanishi & Komatsu, 2017 ) are also influenced by a height of water column above the bottom depending on the bottom depth. Coastal reconstructions, including the construction of large seawalls, breakwaters, and roads, could also affect the shallow bottom near the coast where ecotone between land and the sea is extended in coastal waters ( Komatsu et al, 2012 ; Komatsu et al, 2018a ). Therefore, long-term monitoring of post-tsunami coastal ecosystems were essential to assess the coastal environments.…”

Section: Introductionmentioning

confidence: 99%

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Monitoring oyster culture rafts and seagrass meadows in Nagatsura-ura Lagoon, Sanriku Coast, Japan before and after the 2011 tsunami by remote sensing: their recoveries implying the sustainable development of coastal waters

Murata

Hara

Yonezawa

et al. 2021

PeerJ

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Background Coastal ecosystems are blue infrastructures that support coastal resources and also aquaculture. Seagrass meadows, one of coastal ecosystems, provide substrates for epiphytic diatoms, which are food resources for cultured filter feeder organisms. Highly intensive coastal aquaculture degrades coastal environments to decrease seagrass meadows. Therefore, efficient aquaculture management and conservation of seagrass meadows are necessary for the sustainable development of coastal waters. In ria-type bays, non-feeding aquaculture of filter feeders such as oysters, scallops, and ascidians are actively practiced along the Sanriku Coast, Japan. Before the 2011 Great East Japan Earthquake, the over-deployment of oyster culture facilities polluted the bottom environment and formed an hypoxic bottom water layer due to the organic excrements from cultured oysters. The tsunami in 2011 devastated the aquaculture facilities and seagrass meadows along the Sanriku Coast. We mapped the oyster culture rafts and seagrass meadows in Nagatsura-ura Lagoon, Sanriku Coast before and after the tsunami and monitored those and environments after the tsunami by field surveys. Methods We conducted field surveys and monitored the environmental parameters in Nagatsura-ura Lagoon every month since 2014. We used high-resolution satellite remote sensing images to map oyster culture rafts and seagrass meadows at irregular time intervals from 2006 to 2019 in order to assess their distribution. In 2019, we also used an unmanned aerial vehicle to analyze the spatial variability of the position and the number of ropes suspending oyster clumps beneath the rafts. Results In 2013, the number and distribution of the oyster culture rafts had been completely restored to the pre-tsunami conditions. The mean area of culture raft increased after the tsunami, and ropes suspending oyster clumps attached to a raft in wider space. Experienced local fishermen also developed a method to attach less ropes to a raft, which was applied to half of the oyster culture rafts to improve oyster growth. The area of seagrass meadows has been expanding since 2013. Although the lagoon had experienced frequent oyster mass mortality events in summer before the tsunami, these events have not occurred since 2011. The 2011 earthquake and tsunami deepened the sill depth and widened the entrance to enhance water exchange and improve water quality in the lagoon. These changes brought the expansion of seagrass meadows and reduction of mass mortality events to allow sustainable oyster culture in the lagoon. Mapping and monitoring of seagrass meadows and aquaculture facilities via satellite remote sensing can provide clear visualization of their temporal changes. This can in turn facilitate effective aquaculture management and conservation of coastal ecosystems, which are crucial for the sustainable development of coastal waters.

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“…However, human population growth [16] is placing increasing pressure on coastal ecosystems [17]. Most of the seagrass species of the world are already under threat or diminishing [4,8,18], due to human activities and economic development in coastal zones (e.g., [19,20]). Thus, mapping and monitoring of seagrass meadows we developed a method to map seagrass meadows and estimate their relative abundance on sand beds by using only bathymetry data which simplify post-process analysis.…”

Section: Introductionmentioning

confidence: 99%

Real-Time Classification of Seagrass Meadows on Flat Bottom with Bathymetric Data Measured by a Narrow Multibeam Sonar System

Hamana

Komatsu

2016

Remote Sensing

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Seagrass meadows, one of the most important habitats for many marine species, provide essential ecological services. Thus, society must conserve seagrass beds as part of their sustainable development efforts. Conserving these ecosystems requires information on seagrass distribution and relative abundance, and an efficient, accurate monitoring system. Although narrow multibeam sonar systems (NMBSs) are highly effective in resolving seagrass beds, post-processing methods are required to extract key data. The purpose of this study was to develop a simple method capable of detecting seagrass meadows and estimating their relative abundance in real time using an NMBS. Because most seagrass meadows grow on sandy seafloors, we proposed a way of discriminating seagrass meadows from the sand bed. We classify meadows into three categories of relative seagrass abundance using the 95% confidence level of beam depths and the depth range of the beam depth. These are respectively two times the standard deviation of beam depths, and the difference between the shallowest and the deepest depths in a 0.5ˆ0.5 m grid cell sampled with several narrow beams. We examined Zostera caulescens Miki, but this simple NMBS method of seagrass classification can potentially be used to map seagrass meadows with longer shoots of other species, such as Posidonia, as both have gas filled cavities.

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Mapping is a Key for Sustainable Development of Coastal Waters: Examples of Seagrass Beds and Aquaculture Facilities in Japan with Use of ALOS Images

Abstract: Hard cover, 342 pagesPublisher InTech

Cited by 10 publications

References 16 publications

Basin-scale seasonal changes in marine free-living bacterioplankton community in the Ofunato Bay

Basin-scale seasonal changes in marine free-living bacterioplankton community in the Ofunato Bay

Monitoring oyster culture rafts and seagrass meadows in Nagatsura-ura Lagoon, Sanriku Coast, Japan before and after the 2011 tsunami by remote sensing: their recoveries implying the sustainable development of coastal waters

Real-Time Classification of Seagrass Meadows on Flat Bottom with Bathymetric Data Measured by a Narrow Multibeam Sonar System

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