Long Term Changes in Sea Surface Temperature Around Habitat Ground of Walleye Pollock (&lt;i&gt;Gadus chalcogrammus&lt;/i&gt;) in the East Sea

Seol, Kangsu; Researcher, Gyeonggi Province Maritime; Lee, Chung Il; Jung, Hae-Kun

doi:10.7837/kosomes.2020.26.2.195

Cited by 7 publications

(10 citation statements)

References 8 publications

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“…In the experiment, the eggs were placed on surface grids, taking their density into account. The spawning grids were determined by their suitable spawning temperature range (2 °C-5 °C) and the appropriate habitat depths (50-500 m) for walleye pollock [10,21,[50][51][52]. We considered the potential spawning ground located in the EKB between 36°N and 41°N (figure 1(b)).…”

Section: Particle Tracking Experimentsmentioning

confidence: 99%

“…The East Korea Bay (EKB) off the coast of Korea is known as a major spawning ground for walleye pollock in the EJS (figure 1) [8][9][10], and the species living in the Korean fishing area spawn in the bay [10,11]. In contrast to the stable catches in Japan and Russia, the catch in Korea has significantly declined since the 2000s and has not yet fully recovered [4,9].…”

Section: Introductionmentioning

confidence: 99%

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Severe reduction in spawning days and larval abundance of walleye pollock under future warming in the western East/Japan Sea

Kim,

Lee,

Kim

et al. 2024

Environ. Res. Commun.

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The collapse of walleye pollock catch in the Korean fishing region during the late 1980s remains unresolved despite enormous efforts to recover its stock. To investigate the future fate of walleye pollock in the western East/Japan Sea (EJS) in the late 21st century, we implemented a dynamical downscaling approach by developing high-resolution regional ocean climate models (1/20°) with the selected Coupled Model Intercomparison Project 6 (CMIP6) global climate models. We analyzed the changes in the spawning area and larval distribution of walleye pollock in the western EJS. Under the SSP5-8.5 global warming scenario, the suitable spawning period ratio of walleye pollock was drastically reduced by 76%. The severe reduction in spawning grounds in the western EJS was mainly attributed to ocean warming caused by a decrease in atmospheric surface cooling. Moreover, our particle tracking experiment showed substantial loss of eggs and larvae south of 38°N. Our study projected a drastic collapse of walleye pollock in the western EJS and proposed a variety of collapse patterns based on local circulation under future warming conditions. These findings can help the local fishing industry adapt and assist neighboring governments in planning future fisheries management strategies.

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Section: Particle Tracking Experimentsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Severe reduction in spawning days and larval abundance of walleye pollock under future warming in the western East/Japan Sea

Kim,

Lee,

Kim

et al. 2024

Environ. Res. Commun.

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“…First, as the heat-dome phenomenon becomes stronger due to the strengthening of the power of the North Pacific high pressure and the influence of Tibetan high pressure, the duration and frequency of the heat wave continued to grow [34,35]. Second, the power of the Tsushima warm current, which supplies heat at low latitudes, has been showing strong in the summer in Korea in recent years [36,37]. Third, since the frequency of typhoons that were concentrated in July and August every year decreased, the external force to mix the high-temperature surface sea water with the low-temperature sea water was weakened.…”

Section: Study Areamentioning

confidence: 99%

Sea Surface Temperature and High Water Temperature Occurrence Prediction Using a Long Short-Term Memory Model

2020

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Recent global warming has been accompanied by high water temperatures (HWTs) in coastal areas of Korea, resulting in huge economic losses in the marine fishery industry due to disease outbreaks in aquaculture. To mitigate these losses, it is necessary to predict such outbreaks to prevent or respond to them as early as possible. In the present study, we propose an HWT prediction method that applies sea surface temperatures (SSTs) and deep-learning technology in a long short-term memory (LSTM) model based on a recurrent neural network (RNN). The LSTM model is used to predict time series data for the target areas, including the coastal area from Goheung to Yeosu, Jeollanam-do, Korea, which has experienced frequent HWT occurrences in recent years. To evaluate the performance of the SST prediction model, we compared and analyzed the results of an existing SST prediction model for the SST data, and additional external meteorological data. The proposed model outperformed the existing model in predicting SSTs and HWTs. Although the performance of the proposed model decreased as the prediction interval increased, it consistently showed better performance than the European Center for Medium-Range Weather Forecast (ECMWF) prediction model. Therefore, the method proposed in this study may be applied to prevent future damage to the aquaculture industry.

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“…However, pollock production in Japan and Russia has either remained stable or slightly increased after 2000 [8], while the pollock catch in the United States and Canada, situated in the North Pacific, has not continued to decline since 2000 but has instead maintained a stable level [8]. In Korean waters, pollock fisheries have also undergone a drastic decline since the late 1980s, with catches plummeting below 1000 tons, nearly reaching extinction since 2000, in contrast to production in other countries [7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

“…To determine the cause of changes in catches of fisheries, it is essential to consider the simultaneous impacts of human activities such as overfishing and changes in the physical environment of habitats and spawning grounds. Recent studies aiming to understand the fluctuations in pollock catch have focused on changes in the oceanic and biological conditions around spawning grounds [9,17].…”

Section: Introductionmentioning

confidence: 99%

The Long-Term Dynamics of Walleye Pollock Stocks in Relation to Oceanographic Changes in the East Sea

Jung,

Park,

Yang

et al. 2024

Water

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The decline in walleye pollock (Gadus chalcogrammus) stocks in Korean waters is a major concern for fishery conservation and management. However, the causes and mechanisms of this collapse remain unclear. This study investigated the complex dynamics influencing the abundance of walleye pollocks in the East Sea of Korea over several decades, by analyzing data from long-term changes in biological factors including composition of length and sex, catch, and oceanographic condition. Prior to the mid-1980s, the catch ratio of juveniles was higher than that of adults, with a higher proportion of females in both juvenile and adult catches compared to males. Especially, high fishing pressure on female individuals can be an important factor contributing to declining reproduction. Consequently, after the mid-1980s, there was a sudden decline in juvenile pollock catches. In the late 1980s, there was a rapid increase in sea surface temperature (SST) in the spawning grounds, resulting in a decrease in both the duration of suitable temperature for spawning and the regional proportion for suitable spawning conditions. Consequently, the decline in pollock stocks after the late 1980s due to overfishing of pollock in the mid-1980s was further exacerbated by the effects of SST warming after the late 1980s. These findings highlight the impact of overfishing and environmental factors on pollock stocks and indicate the need for appropriate fishery management practices to ensure the sustainable use of fishery resources.

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Long Term Changes in Sea Surface Temperature Around Habitat Ground of Walleye Pollock (<i>Gadus chalcogrammus</i>) in the East Sea

Cited by 7 publications

References 8 publications

Severe reduction in spawning days and larval abundance of walleye pollock under future warming in the western East/Japan Sea

Severe reduction in spawning days and larval abundance of walleye pollock under future warming in the western East/Japan Sea

Sea Surface Temperature and High Water Temperature Occurrence Prediction Using a Long Short-Term Memory Model

The Long-Term Dynamics of Walleye Pollock Stocks in Relation to Oceanographic Changes in the East Sea

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