Navigation Links
Scripps scientists peg wind as the force behind fish booms and busts
Date:2/5/2008

The mid-20th century crash of the sardine fishery off California for decades has vexed marine ecologists searching for the root causes of large fluctuations in the sardine population. Before its collapse, the fishery was one of the worlds most productive and formed the setting of John Steinbecks Cannery Row in Monterey, Calif.

Scientists at Scripps Institution of Oceanography at UC San Diego have now shed light on the puzzle by proposing a plausible mechanism behind the mystery: wind.

Writing in the online early edition of the Proceedings of the National Academy of Sciences, Scripps researchers Ryan Rykaczewski and David Checkley propose that atmospheric wind forces can determine the availability of microscopic organisms that sardine and anchovy feed upon. When wind causes nutrient-rich waters to rise to the surface, plankton levels increase and sardine populations flourish. Conversely, sardine numbers crash when plankton become scarce as wind conditions change.

The scientists say their findings may explain the sardine and anchovy booms and busts off Californias coast and could explain similar population cycles elsewhere around the world.

This paper is the first to show a mechanistic relationship between climate variability and the sardine fishery, said Rykaczewski, a Scripps graduate student researcher. There have been a lot of hypotheses about climate change and sardine and anchovy fisheries, but there has been little scientific support for a mechanism connecting changes in climate to changes in these fish populations.

After a sardine collapse that began in the late 1940s, scientists sought a greater ecological understanding of the California Current, the eastern portion of the clockwise circulation of the North Pacific Ocean that flows off Californias coast. This need led to the 1949 launch of the California Cooperative Oceanic Fisheries Investigations (CalCOFI), a unique ocean dynamics monitoring program initiated by Scripps Institution, the California Department of Fish and Game and the National Oceanic and Atmospheric Administrations National Marine Fisheries Service, which continues today.

The 50-plus years of CalCOFI data were key to Rykaczewski and Checkleys scientific breakthrough. In addition, research cruises conducted in association with the California Current Ecosystem Long-Term Ecological Research Program allowed the scientists to take a closer look at the relationship between plankton and winds. Rykaczewski also worked with Scripps climate researcher Masao Kanamitsu to compare historic ocean wind patterns with ecological data.

Thats the key, said Checkley a Scripps professor. The rate at which water moves vertically influences the structure of the marine ecosystems out there. Thats the seminal part of this theory.

Rykaczewski and Checkley determined that two atmospheric conditions were the main drivers: coastal upwelling, in which wind forces a rapid rise in cold, nutrient-rich waters from the ocean depths; and a comparable process called wind-stress curl upwelling that occurs offshore in the open ocean.

In both cases, the wind drives upwelling, which supplies the surface ocean with the nutrients necessary to support plankton and fish populations. In the coastal zone, rapid upwelling supports the largest zooplankton, which are the favored prey of anchovies, which possess coarse gill rakersakin to a mesh filtering mechanismfor consuming plankton. In the open ocean, slower but more extensive upwelling sustains a much smaller class of zooplankton, suitable for sardines and their comparatively fine gill rakers.

The scientists say their research suggests that sardines and anchovies do not compete against one another, but rather each takes advantage of the zooplankton available as the climate and winds change.

This research furthers the idea that fluctuations can be explained by natural phenomena as opposed to fishing exclusively, said Checkley. I think theres no question that both fishing and natural forcing are responsible for the historical fluctuations in fish not only off California, but off Peru, Japan, South Africa and Spain. Its important to realize that nature is a large player in this equation, if not the dominant one.

Rykaczewski and Checkley say the new study could be important for fisheries management by paving the way for a new approach of predicting fish populations using climate change and wind factors.

Thats important for management because we now know we need to use an ecosystem-based approach for fisheries management, said Rykaczewski.


'/>"/>

Contact: Mario Aguilera
scrippsnews@ucsd.edu
858-534-3624
University of California - San Diego
Source:Eurekalert  

Related medicine news :

1. Scripps Research scientists shed new light on how antibodies fight HIV
2. Scripps Health Treats More Than 160 Fire Victims at Emergency Departments Across San Diego County
3. Scripps research scientists discover chemical triggers for aggression in mice
4. Scripps research scientists find new genetic mutation that halts the development of lupus
5. Scripps scientists find calcium channel blockers help normalize lysosomal storage disease cells
6. New prion protein discovered by Canadian scientists may offer insight into mad cow disease
7. Scientists Probe Sepsis Deadly Secrets
8. Scientists puzzled by severe allergic reaction to cancer drug in the middle Southern US
9. Scientists Develop Natural Protection for Stored Foods
10. Scientists detect presence of marburg virus in african fruit bats
11. Scientists Spot Brains Free Will Center
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Scripps scientists peg wind as the force behind fish booms and busts
(Date:2/17/2017)... ... February 17, 2017 , ... ... its educational assistance management solution to the exhibit floor for the 2017 ... Fla. , From Feb. 19–23, 2017, more than 40,000 healthcare industry professionals ...
(Date:2/17/2017)... Verdes, CA (PRWEB) , ... February 17, 2017 ... ... emotional flow is Dr. Carol Francis' goals for each and every ... Conference, Dr. Carol Francis will demonstrate five different brainwave tools which help energize ...
(Date:2/17/2017)... ... February 17, 2017 , ... Qualis ... a finalist in the 8th Annual DecisionHealth Platinum Awards in recognition of its ... Health’s work is recognized across multiple award categories, highlighting four of the organization’s ...
(Date:2/17/2017)... , ... February 17, 2017 , ... ... fall 2017 season , Trinity Health and the U.S. Soccer Foundation announced today ... program in underserved communities. Soccer for Success, the Foundation’s soccer mentoring program, teaches ...
(Date:2/17/2017)... (PRWEB) , ... February 17, 2017 , ... ... clinical operations executives and focusing on all facets of clinical trial planning and ... management , patient engagement, and more. In addition, attendees stopping by Pharmica’s booth ...
Breaking Medicine News(10 mins):
(Date:2/16/2017)... LOUIS , Feb. 16, 2017  Express Scripts (NASDAQ: ... of the World,s Most Admired Companies within the Health Care: Pharmacy ... be named one of the World,s Most Admired Companies," said ... driven by the commitment and passion of our 26,000 employees to ... we serve." ...
(Date:2/16/2017)... , Feb. 16, 2017  Prescription pain medications ... department visit are necessary for long-term opioid use to ... Feb. 16 th edition of The New ... "Emergency physicians see more patients in acute pain than ... Parker , MD, FACEP, president of the American College ...
(Date:2/16/2017)... 16, 2017   Spectralink Corporation , the ... healthcare, retail, manufacturing and hospitality industries, today announced ... and symbology support features of its PIVOT™:SC ... scanner. The study, conducted by The Tolly Group, ... two phones with dedicated hardware scanners. ...
Breaking Medicine Technology: