Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Research Shows Overfishing of Sharks Key Factor in Coral Reef Decline

12.04.2005


Unprecedented study describes sources contributing to decline of Caribbean reefs



Their position at the pinnacle of the marine food chain is legendary. Now, understanding sharks and their significance as top predators-and the consequences of human activity towards them-has taken on new importance through a new study by scientists in San Diego and Spain.

Jordi Bascompte and Carlos Melián of the Integrative Ecology Group, Estación Biológica de Doñana, Consejo Superior de Investigaciones Científicas, in Sevilla, Spain, and Enric Sala of Scripps Institution of Oceanography at the University of California, San Diego, developed an unprecedented model of a Caribbean marine ecosystem and details of its intricate predator-prey interactions. This food "web" covered 1,000 square kilometers to a depth of 100 meters and included some 250 species of marine organisms. The study, published in the April 12 edition of the Proceedings of the National Academy of Sciences, included an intricate network of more than 3,000 links between these species. The project was one of the largest and most detailed investigations of marine food webs and the first study to integrate food web structure, dynamics and conservation.


One of the most striking products of the study is a stark picture of human impacts on marine ecosystems and the consequences of targeted fishing. In the Caribbean, overfishing of sharks triggers a domino effect of changes in abundance that carries down to several fish species and contributes to the overall degradation of the reef ecosystem. Overfishing species randomly, the study shows, is not likely to cause these cascading effects.

"It appears that ecosystems such as Caribbean coral reefs need sharks to ensure the stability of the entire system," said Sala, deputy director of the Center for Marine Biodiversity and Conservation at Scripps.

When sharks are overfished, a cascade of effects can lead to a depletion of important grazers of plant life. This is because there are fewer sharks to feed on carnivorous fish such as grouper-causing an increase in their numbers and their ability to prey on parrotfishes. The removal of plant-eating animals such as parrotfishes has been partly responsible for the shift of Caribbean reefs from coral to algae dominated, the authors note. Thus overfishing of sharks may contribute further to the loss of resistance of coral reefs to multiple human disturbances.

"The community-wide impacts of fishing are stronger than expected because fishing preferentially targets species whose removal can destabilize the food web," the authors conclude in their report.

Because of their comprehensive approach in developing the intricate food web, the authors say their study and its results address more than individual species protection and speak to larger ecosystem protection issues. "The paper presents a community-wide approximation of conservation problems," said Bascompte. "We cannot asses all of the implications of overfishing by only looking at the target species or a few others. Species are embedded in a complex network of relationships and this network has a particular shape. This has large implications for the propagation of the consequences of overfishing through the whole food web."

Funding for the study was provided by the Spanish Ministry of Science and Technology and a grant from the History of Marine Animal Populations Program of the Census of Marine Life, which was sponsored by the Alfred P. Sloan Foundation.

Scripps Institution of Oceanography, at the University of California, San Diego, is one of the oldest, largest, and most important centers for global science research and graduate training in the world. The National Research Council has ranked Scripps first in faculty quality among oceanography programs nationwide. The scientific scope of the institution has grown since its founding in 1903 to include biological, physical, chemical, geological, geophysical, and atmospheric studies of the earth as a system. Hundreds of research programs covering a wide range of scientific areas are under way today in 65 countries. The institution has a staff of about 1,300, and annual expenditures of approximately $140 million from federal, state, and private sources. Scripps operates one of the largest U.S. academic fleets with four oceanographic research ships and one research platform for worldwide exploration.

Mario Aguilera | EurekAlert!
Further information:
http://www.ucsd.edu

More articles from Ecology, The Environment and Conservation:

nachricht Scientists produce a new roadmap for guiding development & conservation in the Amazon
09.12.2016 | Wildlife Conservation Society

nachricht Successful calculation of human and natural influence on cloud formation
04.11.2016 | Goethe-Universität Frankfurt am Main

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>