Reef sharks are so-called apex predators on tropical coral reefs and are therefore of significant potential importance to the functioning of coral reef ecosystems. The reproductive biology of reef sharks makes them particularly vulnerable to fishing, but until now, there have been no studies of the response of these sharks to fishing pressure.
The new work focused on Australia’s Great Barrier Reef, which is widely considered to be one of the world’s least degraded, and best managed, reef systems. For balancing conservation with sustainable use, the Great Barrier Reef is regulated through an extensive series of management zones in which different areas are open to different levels of fishing. In their study, the researchers determined the status of two species of reef shark—the whitetip and grey reef sharks—by employing a unique combination of fisheries-independent abundance estimates and measurements of the survival and reproduction of individual sharks. Their findings show that reef shark abundance on reefs open to fishing are about ten times lower than on unfished reefs.
Moreover, high reef shark abundance was only apparent on the most strictly enforced of the no-take zones, suggesting that even moderate levels of poaching can derail attempts to protect shark populations. These observations, coupled with population modeling showing ongoing, rapid declines in population size in fished areas, lead the authors to conclude that reef sharks are approaching “ecological extinction”—that is, becoming so rare that they can no longer perform their natural role in the functioning of coral reef ecosystems.
Heidi Hardman | EurekAlert!
International network connects experimental research in European waters
21.03.2017 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)
World Water Day 2017: It doesn’t Always Have to Be Drinking Water – Using Wastewater as a Resource
17.03.2017 | ISOE - Institut für sozial-ökologische Forschung
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
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22.03.2017 | Materials Sciences