Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Young chum salmon may get biggest nutrition boost from Elliott Bay restored beaches

16.09.2015

In the midst of ferry boats, container ships and tourists crowding Seattle's Elliott Bay, young salmon are just trying to get a decent meal.

The fish hatch in the rivers and streams that feed into Puget Sound and almost immediately rely on eating small organisms near the shore, including in the heart of Seattle's commerce-filled waterfront.


University of Washington researchers sample for young salmon and invertebrates along a restored beach at Seacrest Park in Seattle's Elliott Bay.

Credit: University of Washington

Though salmon share the busy Elliott Bay waters with boats and barges, scientists suspect built-up, "armored" shorelines and large piers may be the main culprits disrupting fish habitat. These artificial structures block light and confuse the fish as they make their way to the ocean.

But are concrete seawalls actually affecting what the salmon eat, and by how much? A University of Washington study shows that it depends on the species, with small chum salmon seeming to be most affected.

The study looked at the diets of young salmon passing through Elliott Bay. Researchers measured the types of prey in the water along armored shorelines and along restored beaches. Scientists then collected young salmon in nets -- corralled by boats or divers -- and flushed out their stomachs to look at what they ate recently.

The stomach contents showed that young pink and Chinook salmon that feed on organisms either floating in the water or on the water's surface were able to eat the same amount of food, whether they were feeding near a concrete shoreline such as Seattle's ferry terminal at Coleman Dock or along shoreline that has been restored to look like a natural beach, including along Seattle Art Museum's Olympic Sculpture Park.

However, young chum salmon that munch on critters found mainly in bottom habitats had a noticeable change in their eating patterns depending on the type of shoreline. These small chum salmon ate more invertebrates floating in the water when swimming by armored sites, and more bottom-dwelling crustaceans -- which they prefer -- when feeding near beaches. Larger juvenile chum behaved more like their pink and Chinook counterparts.

"Our study shows that armoring affects what species of prey are available," said lead author Stuart Munsch, a UW doctoral student in aquatic and fishery sciences. "Fish that normally eat those missing prey will feed on alternative species at armored sites, but we don't know what the costs of that change are to the fish."

The findings were published Sept. 15 in the journal Marine Ecology Progress Series.

The article details the latest in a series of recent studies along Seattle's waterfront that is trying to better understand how fish behave in urban, industrial waterways. The shores of Elliott Bay are almost fully walled-in with concrete and riprap, a layer of large stones designed to keep soil from eroding. The most natural shorelines are along several manmade sandy beaches, restored recently for public recreation and natural beauty.

The study confirmed that areas converted to look like beaches attract more diverse organisms, including small crustaceans known as harpacticoid copepods. These weren't seen much along armored shorelines, which instead had more barnacles -- not an appetizing choice for young salmon.

"Engineered shorelines like these manmade beaches are going to have more components of a natural ecosystem than a featureless wall," said co-author Jeff Cordell, lead investigator on the project and a UW research scientist with aquatic and fishery sciences. "Manmade beaches will produce more diversity and numbers of the kinds of food juvenile salmon utilize."

The researchers found that while the types of organisms in the water did indeed change depending on shoreline, only the small chum salmon actually adjusted what they ate.

Maybe the other fish, the pink, Chinook and larger chum salmon, ate prey that wasn't directly affected by the type of shorelines present -- such as plankton, which was in the water at both locations -- or were large and strong enough to swim through both areas, eating along the way, before their stomach contents were measured.

But small chum salmon are especially dependent on the tiny crustaceans more common along restored beach sites. And while none of the fish studied were starving, the fish whose diets changed may have used up considerable energy trying to keep a balanced diet.

"The [type of] copepods that chum salmon usually feed on are brightly colored and they're found near the bottom," Munsch said. In other words, the chum's typical diet is easy prey. "We think that chum salmon along armored shorelines might have to spend more energy searching for prey that are harder to see, or chasing prey that are more evasive, when that energy should be allocated to growth or migration."

This study and other recent papers by Cordell's research team are informing Seattle's Seawall Project, which is replacing the current waterfront wall with a structure that intends to be friendlier to fish while protecting city infrastructure.

###

The research was funded by the Seattle Department of Transportation and a National Science Foundation Graduate Research Fellowship. Jason Toft, a research scientist in UW fisheries, is another co-author on this paper.

For more information, contact Cordell at jcordell@uw.edu or 206-543-7532 and Munsch at smunsch@uw.edu.

Media Contact

Michelle Ma
mcma@uw.edu
206-543-2580

 @UW

http://www.washington.edu/news/ 

Michelle Ma | EurekAlert!

More articles from Earth Sciences:

nachricht NASA sees quick development of Hurricane Dora
27.06.2017 | NASA/Goddard Space Flight Center

nachricht Collapse of the European ice sheet caused chaos
27.06.2017 | CAGE - Center for Arctic Gas Hydrate, Climate and Environment

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Collapse of the European ice sheet caused chaos

27.06.2017 | Earth Sciences

NASA sees quick development of Hurricane Dora

27.06.2017 | Earth Sciences

New method to rapidly map the 'social networks' of proteins

27.06.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>