Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Timing is Everything for Northern Shrimp Populations in the North Atlantic

12.05.2009
Early Indicator of Changes in Climate, Ecosystems

Even for Northern shrimp (Pandalus borealis), which support commercial fisheries worldwide, timing is everything in life. The tiny creatures, eaten in shrimp rolls and shrimp salad, occupy a pivotal role in the oceanic food chain and may serve as early indicators of changing climate due to their sensitivity to temperature. Northern shrimp also seem to have an uncanny sense of reproductive timing, releasing their larvae to match the arrival of food and thus maximizing larval survival.

In a study to be published May 8 in the journal Science, Anne Richards of NOAA’s Northeast Fisheries Science Center (NEFSC) laboratory in Woods Hole, Mass. and international colleagues evaluated the timing of the annual shrimp hatch between 1998 and 2007 in populations or stocks at different latitudes across the North Atlantic Ocean from Maine to Norway. The researchers also estimated the timing of spring phytoplankton blooms - the major source of food for the shrimp larvae - in each location using satellite images that show biological productivity in surface waters, commonly called ocean color.

“In the Gulf of Maine we have seen years when there is a good match in timing between when shrimp larvae are released and when the annual spring bloom begins. In these years larvae tend to have high survival rates, resulting in large year classes and a very successful fishery,” said Richards, who has been studying Northern shrimp for almost two decades. “In other years that timing is off, leading to lower survival rates and a poorer fishery. The match or mismatch between the larvae and their food appears to be a key factor in shrimp production.”

The Science study looked at stocks of Northern shrimp, also called pink shrimp, in the Gulf of Maine, on the Scotian Shelf and in the Gulf of St. Lawrence, off Newfoundland and Labrador, on the Flemish Cap, off western Greenland and Northern Iceland, in the Barents Sea and off Svalbard, a group of islands between Norway and the North Pole.

The spring phytoplankton bloom occurs at different times in different latitudes because sunlight and sea surface temperatures, the primary triggers for onset of blooms, vary among regions. The researchers found a surprising tendency in each location for the shrimp eggs to hatch and the larvae to appear just as the bloom arrived.

“The interesting thing is that the timing of the hatch is strongly dependent on temperature on the ocean bottom, but the timing of the bloom is a function of several factors, including temperature throughout the water column and available sunlight,” Richards said. “Yet, on average, in most of these locations, there is a close match between the hatch and the bloom. It makes perfect sense from an evolutionary perspective, but it is still surprising. Before the advent of satellite imagery, it would have been very difficult to be able to demonstrate this phenomenon across a wide geographic area.”

The time it takes for shrimp eggs to develop into young shrimp, or larvae, varies significantly depending on local bottom water temperatures. In the southern Gulf of Maine off Cape Cod, the waters are relatively warm and shrimp eggs take six months to hatch, while in the cold waters off Northern Iceland the eggs take 9-10 months to hatch. This suggests that the time of mating must have evolved so the larvae are ready to hatch near the time of the bloom under average temperature conditions for each area.

Northern shrimp may serve as an early indicator of the impact of climate change since their life cycle is very temperature dependent. The species breeds once a year, usually in the summer/fall, with the female carrying eggs on her abdomen much like lobsters do until they hatch the following winter/spring. Although the shrimp live most of their life in colder bottom waters, once the eggs hatch the young shrimp live near the surface for several months feeding on phytoplankton and larger zooplankton.

The authors say changing climate may increase bottom water temperatures, resulting in shorter development times for the eggs. If so, the eggs may hatch too early and be too far ahead of the spring bloom for optimum survival. However, they also say this “mismatch” in timing might not occur if warmer sea surface temperatures result in earlier spring blooms.

Richards is testing the “match-mismatch” hypothesis suggested in this study in more detail in her own research on the Gulf of Maine shrimp stock. So far, she has found a strong relationship between water temperatures, the timing and amount of plankton in surface waters, and shrimp survival rates.

“The warming trends evident in the waters in the Northeast U.S. are likely to have an impact on shrimp recruitment and survival," Richards said. "Shrimp production may be much more variable in the future as the Gulf of Maine warms. The population there may ultimately decline if temperatures continue to increase unless the shrimp can adapt.”

Lead author of the study was Peter Koeller of the Bedford Institute of Oceanography in Canada. In addition to Richards, other authors were from the United Kingdom, Canada, Iceland, Denmark, and Norway. Richards work was supported in part by the Fisheries and the Environment (FATE) program at the U.S. National Marine Fisheries Service.

NOAA Fisheries Service is dedicated to protecting and preserving our nation’s living marine resources and their habitat through scientific research, management and enforcement. NOAA Fisheries Service provides effective stewardship of these resources for the benefit of the nation, supporting coastal communities that depend upon them, and helping to provide safe and healthy seafood to consumers and recreational opportunities for the American public.

NOAA understands and predicts changes in the Earth's environment, from the depths of the ocean to the surface of the sun, and conserves and manages our coastal and marine resources.

Shelley Dawicki | EurekAlert!
Further information:
http://www.noaa.gov

More articles from Agricultural and Forestry Science:

nachricht New 3-D model predicts best planting practices for farmers
26.06.2017 | Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign

nachricht Fighting a destructive crop disease with mathematics
21.06.2017 | University of Cambridge

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

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

Im Focus: 3-D scanning with water

3-D shape acquisition using water displacement as the shape sensor for the reconstruction of complex objects

A global team of computer scientists and engineers have developed an innovative technique that more completely reconstructs challenging 3D objects. An ancient...

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

Im Focus: On the way to a biological alternative

A bacterial enzyme enables reactions that open up alternatives to key industrial chemical processes

The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....

Im Focus: The 1 trillion tonne iceberg

Larsen C Ice Shelf rift finally breaks through

A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

 
Latest News

Ultrathin device harvests electricity from human motion

24.07.2017 | Power and Electrical Engineering

Scientists announce the quest for high-index materials

24.07.2017 | Materials Sciences

ADIR Project: Lasers Recover Valuable Materials

24.07.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>