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Yawen Zhang

Publications and source records attributed to Yawen Zhang.

2 recordsLinked to original sources

Quantifying harvestable fish and crustacean production and associated economic values provided by oyster reefs

Quantifying ecosystem services can provide information to justify conservation and restoration decisions so as to allocate limited resources effectively. Consequently, decision makers and public typically ask for simple and understandable information with confidence regarding the availability of the services and the probable economic value. Here, we compiled published information on density enhancement and species life-history information to quantify fish and crustacean production and its uncertainty associated with the current extent of oyster ( Crassostrea virginica ) reefs in Mobile Bay, Alabama. We applied Alabama fishing size limits as a cutoff to exclude the production of non-harvestable size individuals. Fishery landing (2005–2015) and Willingness-To-Pay information were used to quantify the economic benefit of the harvestable production enhancement (commercial and recreational production). Sixteen species were found to be production-enhanced in the bay with a mean of 354 ± 182 g m −2 year −1 , of which 170 ± 112 g m −2 year −1 was economically quantifiable based on their harvestable production and landing information. The mean economic value was $509,000 year −1 in direct economic value for commercial fishers and $19.59 million year −1 estimated by the willingnesstopay value from recreational anglers. The results demonstrated a substantial positive economic benefit of ecosystem services from oyster reefs associated with fishery production in Mobile Bay, Alabama. The method could be applied elsewhere to estimate the economic return from the investment of conserving and restoring of similar structured habitats.

Alabama

An analysis of Twitter responses to the 2019 Ridgecrest Earthquake sequence

Previous research has shown that online social networks can provide valuable insights regarding collective human responses to extreme natural events, such as earthquakes. Most previous studies focused on one large earthquake, while the 2019 Ridgecrest earthquakes involved two significant earthquakes occurring within a short period of time (a M6.4 foreshock on July 4 and a M7.1 mainshock on July 5 in southern California). These earthquakes were the first time in more than a decade that the southern California region, with an estimated population of 15 million, felt light to moderate shaking over an extended period of time. This valuable opportunity allows us to study how people respond dynamically to such sequences of extreme events. We collected 510,579 tweets about the 2019 Ridgecrest earthquakes to answer the following research questions: (1) Which Twitter accounts were the major players? Did they behave differently and get different responses? (2) How did the publics' response change during these sequential earthquakes? and (3) Which earthquake-related rumors were disseminated on Twitter during the earthquake sequence, by whom, and at what time?

California