6 research outputs found
Projecting the Shift of Chub Mackerel (<i>Scomber japonicus</i>) Spawning Grounds Driven by Climate Change in the Western North Pacific Ocean
No full textSpawning grounds may shift due to climate change and subsequent variations in the marine environment, but few studies have aimed to project shifts in the spawning grounds of chub mackerel driven by climate change. We projected the effects of climate change on the spawning grounds of chub mackerel (Scomber japonicus) by developing and applying a suitable spawning ground index based on a regional ocean circulation model for the western North Pacific. Our model indicated that the potential spawning grounds of chub mackerel extended from southern waters of the East China Sea to the Korea Strait, Yellow Sea, and Japan/East Sea. Despite some uncertainty, our model based on climate change scenarios projected that, by the 2050s, spawning grounds will shift northward due to warming of the ocean surface, resulting in a subsequent westward shift of nursery grounds from the Japan/East Sea to the Korea Strait and Yellow Sea. Our projections will contribute to clarifying the impacts of climate change on the distribution of exploitable chub mackerel, the adaptation of fisheries to climate change, and the reliability of stock assessments used for fisheries management in the region
Species Distribution Model-based Habitat Change Projections of the Kelp Species, Ecklonia cava under SSP Scenarios
No full textThe main kelp forest-forming alga Ecklonia cava (E. cava), plays an important role in coastal ecosystems of South Korea. Despite this coastal ecological importance, there is a lack of research on the prediction of macroalgal distribution. In this study, we examined the distribution of E. cava recorded since 1955 and predicted distribution changes starting from 2000, under different climate change scenarios (SSP1-1.9 and SSP5-8.5) using the species distribution model (MAXENT). It reported that E. cava has expanded its range to 38°N latitude since 2000. We found seawater temperature, primary productivity and seawater velocity were controlling factors that determine the habitat of E. cava. Under the low emissions scenario (SSP1-1.9), the habitat suitability and distribution of suitable habitats did not show significant changes. While, under the high emissions scenario (SSP5-8.5), a decline in the southern distribution and an expansion of the northern distribution was predicted. In particular, most of the current habitats of E. cava were found to have decreased habitat suitability, thus the existing population of the species in South Korea may experience a sharp decline. The results of this study can be used as a basis for developing sustainable conservation measures to maintain coastal ecosystems of rocky shore in South Korea.22Nkc
Spatio-Temporal Projections of the Distribution of the Canopy-Forming Algae Sargassum in the Western North Pacific Under Climate Change Scenarios Using the MAXENT Model
No full textCanopy-forming algae play an important role in coastal ecosystems because these species are highly productive and provide habitats and shelter for numerous marine organisms. Sargassum is the main genus of canopy-forming algae in the western North Pacific, but despite the importance of their ecological role, studies on the changes in their distribution are still scarce. Based on the present distribution of four Sargassum species, this study predicted the geographic distribution of future habitats (2030s, 2060s, and 2090s) under three Shared Socioeconomic Pathway (SSP) scenarios. The environmental variables predicted from the sixth phase of the coupled model intercomparison project (CMIP6) had different impacts depending on the species, with current velocity and water temperature showing high contributions in all four species. According to the projections, three Sargassum species (S. horneri, S. macrocarpum, and S. patens) are expected to maintain a higher habitat suitability index (HSI) and suitable habitat (MAXENT ≥ 0.4) through the 2090s under the SSP1-1.9 scenario. However, under the SSP2-4.5 and SSP5-8.5 scenarios, the HSI of the species is projected to gradually decrease in the southern coastal waters of the Korean peninsula and increase in the East Sea (North Korea), with these results intensifying under the SSP5-8.5 scenario. On the other hand, S. piluliferum was found to increase its HSI and habitat under the highest emission scenarios. All Sargassum species are predicted to shift northward from 0.8° N to 3.8° N by the 2090s under the SSP5-8.5 scenario. Although many marine protected areas exist off the coasts of South Korea and Japan, suitable Sargassum habitats were found to be located within protected reserves between 47.1% and 61.2%, depending on the scenario. These findings on Sargassum provide distributional predictions for ecological conservation strategies and provide new evidence for the need for climate change efforts
Long-term changes in fish assemblage structure in the Yellow Sea from 1968 to 2019 in relation to climate change
No full textThe Korean waters, including the Yellow Sea (YS), are one of the most rapidly warming regions in the world's oceans over the past 30 years, and the marine environmental changes have an impact on the distribution of fisheries species. In this study, we evaluated the changes in fish assemblage, and their relationships with oceanographic environments in the YS. For this purpose, we collected commercial fisheries data in the YS from the Sea Around Us and depth-specific oceanographic data from the Korea Oceanographic Data Center. Using these data, we conducted a canonical correspondence analysis (CCA) to analyze the species composition in terms of biomass ratio of fish species from 1968 to 2019 and their relationships with the environmental changes. To detect shifts in the time-series of the two-dimensions from CCA and oceanographic conditions, we applied a sequential t-test of regime shift (STARS). The CCA revealed major shifts in fish assemblage structure between 1988 and 1991, with this change being associated with water temperature at 0, 10, and 50-m depth and salinity at all depths. This shift in fish assemblage structure seemed to be related to the late 1980s climate regime shift in the North Pacific. Further multidisciplinary researches are necessary to identify the oceanographic and biological processes influence climate-driven physical changes to fish recruitment and habitat variations.1
Peculiar Morphology of Montipora millepora Reveals Interspecific Competition for Space Among Two Other Major Foundation Species in Jeju Waters, South Korea
No full textAn atypical surface shape was observed in encrusting coral colonies of Montipora millepora. Initial assumptions on their origin focused on the presence of epibiotic intermediate habitat formers, such as coral-dwelling and -boring organisms. However, further investigations revealed their origin to also be substrate shape-related, prompted by overgrowing other foundation species. The unusual bumps stemmed from encrusting over specimens of the coral Alveopora japonica, and the forked, tube-like structures over holdfasts of the brown alga Ecklonia cava. Spatial distribution patterns and interspecific competition are briefly reviewed. Potential effects of morphological changes for Montipora species identification, as well as implications of altered topography in general, are mentioned
Tracing floating Sargassum in the Yellow Sea and East China Sea using GOCI
No full textThe Yellow Sea (YS) and East China Sea (ECS) have the world’s largest supply of floating algae. The golden tides (Sargassum horneri) causes a huge socioeconomic problem in the vicinity of coastal areas. However, the annual pattern of the golden tide bloom is not well known due to changing air-sea interaction conditions. To understand the spatial and temporal variations, the multi-satellite data was used to detect the floating macroalgae which was determined by the Alternative Floating Algae Index and mapped over the study area using a 17-year data. The floating golden tide patches detected by both satellite data were overlapped to make the annual pattern maps.
The golden tides were generally found on spring in the YS and ECS. The Sargassum blooms was proceeded in the waters near the Yangtze River and Zhejiang Province, China and then floating into the east and northeast ward influenced by the Tsushima warm current or Kuroshio. The Sargassum blooms were build-up in the middle of the ECS and pile-up in the coast of Korea from March to May. Recently, the Sargassum blooms were temporally expanded from October to May from 2019 to 2023. We suggested two origins with tracing the temporal and spatial distribution and development. The first blooms were onset on fall around the Bohai Bay and/or Shandong Peninsula and southward controlled by the local wind and sea surface temperature condition on winter. The second blooms were initiated on winter near the Zhejiang Province, China and eastand northward affected by the local current and wind condition. Although the satellite (e.g. optical and ocean color sensor) have limited to monitor the golden tide blooms under the cloudy, severe weather conditions, small-scale blooms and coastal area, the satellite-detecting golden tide blooms shows promise in the terms of mapping blooms to understand the spatial and temporal distribution and development in regional scale of the YS and ECS.1
