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Temporal distributions of Antarctic krill (Euphausia superba) density and aggregation types were characterized and compared using Nortek Signature100 and SIMRAD Wideband Autonomous Transceiver (WBAT) upward-looking echosounders. Noise varied between the two echosounders. With the Signature100, it was necessary to correct data for background, transient, and impulse noises, while the WBAT data needed to be corrected for background noise only. For selected regions with no visible backscatter, the signal-to-noise ratio of S v values (i.e. the ratio between the signal and the background noise level) did not vary between the two echosounders. Surface echo backscatter was similar during similar time periods. Descriptive metrics were used to quantify spatial and temporal krill vertical distributions: volume backscatter, mean depth, center of mass, inertia, equivalent area, aggregation index, and proportion occupied. Krill backscatter density differed between the two instruments but was detected at similar mean depths. Krill aggregations were identified at each mooring location and classified in three types based on morphological characteristics. Each type of aggregation shape differed at the two spatially separated moorings, while the acoustic density of each aggregation type was similar. The Signature100 detected a lower number of krill aggregations (n  = 133) compared to the WBAT (n  = 707). Although both instruments can be used for autonomous deployment and sampling of krill over extended periods, there is a strong caveat for the use of the Signature100 due to significant differences in noise characteristics and krill detection. [ABSTRACT FROM AUTHOR]

Freshwater fisheries in developing regions provide livelihoods and nutrition for millions of people worldwide. These fisheries are frequently data poor, which limits fisheries management. The seasonal Cambodian dai platform fishery on the Tonle Sap River is one of the best monitored inland fisheries in Southeast Asia, yet catch sampling is limited and there is no fishery-independent monitoring. A monitoring system is needed to characterize fish migration and mortality, be cost effective, and be deployable in areas with minimal infrastructure. We integrated a Simrad wide-band transceiver mini echosounder (200 kHz), solar power, and an Internet of Things communications module as an autonomous, automated monitoring package for the deployment on upstream and downstream commercial fishing platforms. The solar panel and controller supply direct current power to the echosounder, communications module, and battery for power during dark hours. Echosounders are programmed to sample at 1 Hz for 15 min every hour. The communications module is a built cellular endpoint that accesses a local wireless network to transmit raw data files to a data server. Data are downloaded from the server for processing and analysis. This expandable system provides a flexible management tool that can be deployed at any location with wireless communication capability. [ABSTRACT FROM AUTHOR]

An "East Asian Era" is unfolding in the hosting of the Olympic and Paralympic Games and other sports, and nonsports, mega-events. In addition to three editions of the Olympics and Paralympics, several other not as large mega-events have been or are set to be staged in East Asia over the next 5 years. How long the interest in hosting sports mega-events will continue and, if it does, who will be involved in the production of these events are the questions explored in this article. The article consists of five sections. First, we outline the context in which the growth of sports mega-events in the past four decades has occurred. Second, we sketch the theoretical and methodological approaches we use drawing on mobilities research and actor–network theory. Third, studies of knowledge management and policy transfer and mobilities associated with sports mega-events are discussed as a way of understanding the development of mobile mega-event expertise. Fourth, we examine career mobilities, networks, and the extent to which an East Asian "Mega-Event Caravan" could be said to exist or be in formation. Finally, we draw preliminary conclusions and indicate where further research is required. [ABSTRACT FROM AUTHOR]