Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Populations of Peruvian Seabirds Plummeted Due to Increased Fishing Activity, Study Says

03.05.2004


In the late 19th and early 20th centuries, the tens of millions of marine birds living in the "Bird Islands of Peru" became famous around the world. This was due to their appeal as a visual spectacle and because they became economically important as high producers of guano, droppings that the country mined and exported around the world for fertilizer.




A new study published in the current issue of the journal Fisheries Oceanography says the populations of these famous birds have declined dramatically in the last 40 years, largely because the availability of their main food supply, anchovies, once plentiful, has been severely reduced by the Peruvian fishery.

The authors of the study are Jaime Jahncke and George Hunt of the University of California, Irvine, and David Checkley of Scripps Institution of Oceanography at the University of California, San Diego.


The results are the product of a new scientific model developed by Jahncke while studying with Checkley at Scripps Institution. The model characterizes the Peruvian marine ecosystem by cross-referencing natural factors such as wind strength with human influences through fishing activity. "We saw a very different system prior to and after fishing was increased," said Jahncke. "This model gives us a very clear example of how physical processes in the ocean and human influences can limit the populations of these birds, changing them from one state to another."

The Peruvian anchovy fishery, the largest single-species fishery in the world, significantly increased production in the 1950s and ’60s, exporting millions of metric tons of anchovies per year.

The study shows that wind forces in the early part of the 20th century caused a significant rise in the nutrient supply off the Peruvian coast and thereby led to a boom in the anchovy population. With more food available, the numbers of guano-producing seabirds, including cormorants, boobies and pelicans, similarly increased from 1925 to 1955.

But in the decades that followed, the seabird populations declined significantly.

"The decrease," the authors note, "appears to be due to the depletion of their food by the fishery, which grew to catch about 85 percent of the prey otherwise available to the seabirds."

All told, the latter half of the 20th century saw a dramatic decline-from about 20 million seabirds to about five million, according to the paper. Today, many of the so-called bird islands of Peru are largely devoid of seabirds.

"Birds are very visible manifestations of the health of an ecosystem," said Checkley, a professor in the Integrative Oceanography Division at Scripps. "This study demonstrates how fishing can profoundly affect an ecosystem. That’s important because we are coming to a time in the United States and elsewhere in the world when people recognize that fisheries have to be managed not only based upon the dynamics of the individual populations, but on the ecosystem in which they reside. In order to do that we have to understand how fisheries affect the ecosystem and vice versa."

The authors say their study would not have been possible without the prominent leadership and high quality of long-term scientific data provided by the Peruvian fisheries agency, called the Instituto del Mar del Peru (IMARPE). The authors are aware of IMARPE’s effort to change from single-species management to an ecosystem-based approach, and to consider a more reasonable anchovy harvest.

Checkley notes that although the fishery has profoundly impacted the abundance of these birds, a reversal is certainly possible.

"The important point is that we achieve an understanding of the causes of these population changes over time and manage them accordingly," said Checkley. "Once we have the understanding I think it’s really important that management and policy decisions are based on that understanding."
Note: David Checkley is editor-in-chief of Fisheries Oceanography but was not involved in the paper’s review. The paper was reviewed, accepted and coordinated by a separate editor.


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 | UCSD
Further information:
http://scrippsnews.ucsd.edu/article_detail.cfm?article_num=632

More articles from Ecology, The Environment and Conservation:

nachricht How does the loss of species alter ecosystems?
18.05.2017 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig

nachricht Excess diesel emissions bring global health & environmental impacts
16.05.2017 | International Institute for Applied Systems Analysis (IIASA)

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: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

Im Focus: World's thinnest hologram paves path to new 3-D world

Nano-hologram paves way for integration of 3-D holography into everyday electronics

An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...

Im Focus: Using graphene to create quantum bits

In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.

In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

Physicists discover mechanism behind granular capillary effect

24.05.2017 | Physics and Astronomy

Measured for the first time: Direction of light waves changed by quantum effect

24.05.2017 | Physics and Astronomy

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>