Patterns in fish response to seagrass bed loss at the southern Ryukyu Islands, Japan

An extensive seagrass bed on a fringing coral reef at Amitori Bay (southern Ryukyu Islands) disappeared completely in 2009 after a typhoon. Seagrass bed loss had a significant negative influence on not only seagrass bed residents but also commercially important coral reef fishes that utilize seagrass beds as nurseries or feeding grounds. With seagrass bed loss, mean species’ richness and densities of overall seagrass bed fishes per transect decreased by more than 75 and 85%, respectively. Most of the affected fishes were benthivores, piscivores, detritivores, and herbivores. Of 21 dominant species, 13 disappeared completely and 4 showed severe reductions in densities following seagrass bed loss, whereas the densities of 4 bottom-dwelling gobies did not change significantly. Thus, this study demonstrated that most seagrass bed fishes lack the ability to adapt to seagrass habitat loss, suggesting that increasing global seagrass loss will cause serious reductions in seagrass-associated fishes and fishery resources.     

Plant origin of Okinawan propolis: honeybee behavior observation and phytochemical analysis

Propolis is a natural resinous product collected by honeybees from certain plants. It has gained popularity as a food and alternative medicine. Poplar and Baccharis are well known as the source plants of European and Brazilian propolis, respectively. However, the propolis from Okinawa, Japan, contains some prenylflavonoids not seen in other regions such as Europe and Brazil, suggesting that the plant origin of Okinawan propolis is a particular plant that grows in Okinawa. To identify the plant origin of Okinawan propolis, we observed the behavior of honeybees as they collected material from plants and caulked it inside the hive. Honeybees scraped resinous material from the surface of plant fruits of Macaranga tanarius and brought it back to their hive to use it as propolis. We collected samples of the plant and propolis, and compared their constituents by high-performance liquid chromatography with a photo-diode array detector. We also compared their 1,1-diphenyl-2-picryl-hydrazyl radical scavenging activity. The chemical constituents and biological activity of the ethanol extracts of the plant did not differ from those of propolis. This indicates directly that the plant origin of Okinawan propolis is M. tanarius. S. K. and J. N. contributed equally to this work.     

Human and crab exposure to mercury in the Caribbean coastal shoreline of Colombia: impact from an abandoned chlor-alkali plant

Human hair samples from male and female people aged 6-85 years, as well as muscle of crabs (Callinectes sapidus and Callinectes bocourti) were collected from different fishing places along the Caribbean coastal shoreline of Colombia and analyzed for total mercury (T-Hg) in order to establish the impact of mercury-polluted sediments in Cartagena bay on the ecosystem. Hair T-Hg in inhabitants varied between 0.1 and 21.8 microg/g, with average and median of 1.52 microg/g and 1.1 microg/g, respectively. Differences between sampling locations were significant (P<0.01) and median values decreased in the order: Ca?o del Oro (1.5 microg/g)相似文献