High fishery catches through trophic cascades in China

Indiscriminate and intense fishing has occurred in many marine ecosystems around the world. Although this practice may have negative effects on biodiversity and populations of individual species, it may also increase total fishery productivity by removing predatory fish. We examine the potential for this phenomenon to explain the high reported wild catches in the East China Sea—one of the most productive ecosystems in the world that has also had its catch reporting accuracy and fishery management questioned. We show that reported catches can be approximated using an ecosystem model that allows for trophic cascades (i.e., the depletion of predators and consequent increases in production of their prey). This would be the world’s largest known example of marine ecosystem “engineering” and suggests that trade-offs between conservation and food production exist. We project that fishing practices could be modified to increase total catches, revenue, and biomass in the East China Sea, but single-species management would decrease both catches and revenue by reversing the trophic cascades. Our results suggest that implementing single-species management in currently lightly managed and highly exploited multispecies fisheries (which account for a large fraction of global fish catch) may result in decreases in global catch. Efforts to reform management in these fisheries will need to consider system wide impacts of changes in management, rather than focusing only on individual species.

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Hypoxia in the East China Sea: One of the largest coastal low-oxygen areas in the world

Marine Environmental Research ◽

10.1016/j.marenvres.2007.01.007 ◽

2007 ◽

Vol 64 (4) ◽

pp. 399-408 ◽

Cited By ~ 220

Author(s):

Chung-Chi Chen ◽

Gwo-Ching Gong ◽

Fuh-Kwo Shiah

Keyword(s):

East China Sea ◽

East China ◽

Low Oxygen ◽

The East China Sea ◽

China Sea ◽

The World

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Shanghai

Chinese Studies ◽

10.1093/obo/9780199920082-0110 ◽

2015 ◽

Author(s):

Niv Horesh ◽

Jonathan Sullivan

Keyword(s):

East China Sea ◽

Urban Areas ◽

The Body ◽

East China ◽

The East China Sea ◽

Feature Film ◽

Chinese Modernity ◽

China Sea ◽

The World ◽

Huangpu River

Not long after its establishment as a treaty port in 1842, and roughly until the Japanese invasion of China proper in 1937, Shanghai maintained a reputation as one of Asia’s most spellbinding, entrepreneurial, and freewheeling cities. It had served as the mainland China’s commercial, industrial, and cultural hub during that period, and since 1991, it has indisputably re-emerged as China’s second most important city after the capital, Beijing. Yet, although first mentioned by name in Chinese records dating back to the 12th century, Shanghai was not among the 10 most populous cities on the mainland on the eve of Western settlement in 1842. Perched advantageously 15 km downstream from the confluence of the Huangpu River, the Yangtze River (Changjiang), and the East China Sea, Shanghai’s Chinese population numbered around two hundred thousand inhabitants in 1842, most of whom resided within the ancient city walls. By the 1930s, the city’s population exceeded three million, with new neighborhoods sprawling far beyond the historic walled area west of the Huangpu River. Today, the Shanghai Municipality (6,340 sq km) is one of four self-governing urban areas not affiliated with any other province. The city’s perimeters are thus much wider than was the case before 1949, including jurisdiction over fifteen districts, one county, and several offshore islands. Over twenty-three million people now reside in Shanghai, making it the most populous city in China, and one of the largest in the world. Shanghai’s newly built port, sprawling tens of kilometers along the East China Sea, is the busiest in the world, and the skyscrapers in the Pudong district have come to symbolize China’s re-established economic power. Interest in the city’s pre-war legacy has increased in recent years as a result of China’s rapid economic reforms and the opening up of its archives to foreign scholars. Western academics have begun engaging with these newly declassified materials in ways that often reshape our understanding of Chinese modern history. Yet the development path that makes Shanghai so vital to what may be loosely defined as “Chinese modernity,” has not yet been agreed on. One of many testaments to Shanghai’s enduring appeal, is the 2006 CBC television documentary Legendary Cities of Sin, in which Shanghai is portrayed as a megalopolis on par with Paris and Berlin between the two world wars. Shanghai’s mystique is even more potent in the realm of cinema, with scores of Hollywood and Chinese productions set in the pre-Communist era—Ang Lee’s acclaimed feature film Lust, Caution (2007) is an obvious example. Shanghai is also the city where past and present are most studied and written about by China specialists. The body of scholarly literature on post-1842 Shanghai is particularly abundant.

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Natal Origin and Age-Specific Egress of Pacific Bluefin Tuna From Coastal Nurseries Revealed With Geochemical Markers

10.21203/rs.3.rs-199680/v1 ◽

2021 ◽

Author(s):

Jay R. Rooker ◽

R. J. David Wells ◽

Barbara A. Block ◽

Hui Liu ◽

Hannes Baumann ◽

...

Keyword(s):

East China Sea ◽

Sea Of Japan ◽

Marine Ecosystem ◽

Bluefin Tuna ◽

East China ◽

Pacific Bluefin Tuna ◽

The East China Sea ◽

China Sea ◽

Natal Origin ◽

Geochemical Profile

Abstract Geochemical chronologies were constructed from otoliths of adult Pacific bluefin tuna (PBT) to investigate the timing of age-specific egress of juveniles from coastal nurseries (natal sites) in the East China Sea or Sea of Japan to offshore waters of the Pacific Ocean. Element:Ca chronologies were developed for otolith Li:Ca, Mg:Ca, Mn:Ca, Zn:Ca, Sr:Ca, and Ba:Ca, and our assessment focused on the section of the otolith corresponding to the juvenile period (age-0 to age-1+). Next, we applied a common time-series approach (i.e., changepoint analysis) to geochemical profiles to identify divergences presumably linked to inshore-offshore migrations. Conspicuous geochemical shifts were detected during the juvenile interval for Mg:Ca, Mn:Ca, and Sr:Ca that were indicative of coastal-offshore transitions or egress generally occurring for individuals approximately 4-6 mo. old, with later departures (6 mo. or older) linked to overwintering being more limited. Changepoints in ototith Ba:Ca profiles were most common in the early age-1 period (ca. 12-16 mo.) and appear associated with entry into upwelling areas such as the California Current Large Marine Ecosystem following trans-Pacific migrations. Natal origin of PBT was also predicted using the early life portion of geochemical profile in relation to a baseline sample comprised of age-0 PBT from the two primary spawning areas in the East China Sea and Sea of Japan. Mixed-stock analysis indicated that the majority of adult PBT in our sample originated from the East China Sea, but individuals of Sea of Japan origin were also detected our sample of spawning adults collected in the Ryukyu Archipelago.

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Natal origin and age-specific egress of Pacific bluefin tuna from coastal nurseries revealed with geochemical markers

Scientific Reports ◽

10.1038/s41598-021-93298-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Jay R. Rooker ◽

R. J. David Wells ◽

Barbara A. Block ◽

Hui Liu ◽

Hannes Baumann ◽

...

Keyword(s):

East China Sea ◽

Sea Of Japan ◽

Marine Ecosystem ◽

Bluefin Tuna ◽

East China ◽

Pacific Bluefin Tuna ◽

The East China Sea ◽

China Sea ◽

Natal Origin ◽

Geochemical Profile

AbstractGeochemical chronologies were constructed from otoliths of adult Pacific bluefin tuna (PBT) to investigate the timing of age-specific egress of juveniles from coastal nurseries in the East China Sea or Sea of Japan to offshore waters of the Pacific Ocean. Element:Ca chronologies were developed for otolith Li, Mg, Mn, Zn, Sr, and Ba, and our assessment focused on the section of the otolith corresponding to the age-0 to age-1 + interval. Next, we applied a common time-series approach to geochemical profiles to identify divergences presumably linked to inshore-offshore migrations. Conspicuous geochemical shifts were detected during the juvenile interval for Mg:Ca, Mn:Ca, and Sr:Ca that were indicative of coastal-offshore transitions or egress generally occurring for individuals approximately 4–6 mo. old, with later departures (6 mo. or older) linked to overwintering being more limited. Changepoints in otolith Ba:Ca profiles were most common in the early age-1 period (ca. 12–16 mo.) and appear associated with entry into upwelling areas such as the California Current Large Marine Ecosystem following trans-Pacific migrations. Natal origin of PBT was also predicted using the early life portion of geochemical profile in relation to a baseline sample comprised of age-0 PBT from the two primary spawning areas in the East China Sea and Sea of Japan. Mixed-stock analysis indicated that the majority (66%) of adult PBT in our sample originated from the East China Sea, but individuals of Sea of Japan origin were also detected in the Ryukyu Archipelago.

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Finding Approaches to Exploring the Environmental Factors That Influence Copepod-Induced Trophic Cascades in the East China Sea

Diversity ◽

10.3390/d13070299 ◽

2021 ◽

Vol 13 (7) ◽

pp. 299

Author(s):

Tz-Chian Chen ◽

Pei-Chi Ho ◽

Gwo-Ching Gong ◽

An-Yi Tsai ◽

Chih-hao Hsieh

Keyword(s):

East China Sea ◽

Trophic Cascade ◽

C:N Ratio ◽

Trophic Cascades ◽

East China ◽

Size Spectrum ◽

The East China Sea ◽

China Sea

Copepods have been known to be able to cause an increase in phytoplankton through trophic cascades, as copepods consume heterotrophic protists that feed on phytoplankton. However, how the intensity of copepod-induced trophic cascades varies with environmental conditions remains elusive. We hypothesized that a higher proportion of large phytoplankton in the phytoplankton size distribution, a higher stoichiometric quality of phytoplankton, and a higher temperature could mitigate the intensity of a trophic cascade through increasing direct grazing on phytoplankton by copepods. To explore this issue, we quantified the intensity of a trophic cascade as the difference in phytoplankton concentration reduction by grazing using in situ incubations with and without copepods in the East China Sea. We then investigated the relationship between the intensity of trophic cascades versus the slope of the normalized biomass size spectrum (NBSS) of the phytoplankton community, the C:N ratio of particulate organic matter (POM), and temperature. We found that the intensity of trophic cascades weakly decreased with the NBSS slope and increased with temperature; however, both relationships were not statistically significant. We did not find a clear relationship between the strength of the trophic cascades and the C:N ratio of POM. Our results do not support the hypothesis that the proportion of large phytoplankton, the stoichiometric quality of phytoplankton, and the temperature affect trophic cascades. Instead, we suggest that other critical factors, such as protist abundance, play a role in affecting trophic cascades in the plankton food web in the East China Sea. We further propose some issues which should be addressed when conducting in situ shipboard incubation.

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