OREGON STATE UNIVERSITY

college of agricultural sciences

Study finds tropical fish moving into temperate waters

CORVALLIS, Ore. – Tropical herbivorous fish are beginning to expand their range into temperate waters – likely as a result of climate change – and a new international study documents the dramatic impact of the intrusion in the Mediterranean Sea.

Temperate waters are typically dominated by algal “forests” and have naturally low levels and limited diversity of herbivores, the researchers say. But as tropical fish move into these waters, they are consuming much of the plant life and changing the habitat as well as the manner in which different species interact.

Results of the study, which was funded primarily by the Pew Foundation, have just been published in the Journal of Ecology. It builds on a previous study documenting the move of tropical fish species into temperate waters that recently was published in Proceedings of the Royal Society B.

“The introduction of tropical fish into more temperate regions is troubling and this new study gives a vivid example of what can happen when non-native species occupy a new ecosystem,” said Fiona Tomas Nash, a courtesy professor of fisheries and wildlife at Oregon State University and a co-author on both studies.

“We now know that the arrival of tropical fish into temperate areas is occurring on an increasing basis around the world,” she added. “This is the first attempt to characterize what impacts these fish are having – and the mechanisms driving these impacts.”

In this latest study, an international research team surveyed roughly 1,000 kilometers of coastline in the eastern Mediterranean to study two species of tropical fish called rabbitfish. They were introduced to the region through the Suez Canal and now have become a dominant component of the total fish biomass in the southernmost part of the eastern Mediterranean.

This part of the Mediterranean has two distinct areas – one with warmer regions that attract abundant numbers of rabbitfish, and colder regions where they are very rare or completely absent. Where abundant, their damage has been striking: a 65 percent reduction in canopy algae, a 60 percent reduction in overall benthic biomass (algae and invertebrates) and a 40 percent decrease in the total number of plant and animal species.

“The fear is that if the colder regions warm just a bit through climate change or some other mechanism, rabbitfish will begin moving into those areas as well,” Tomas Nash said.

To learn more about how the rabbitfish changed the ecosystem, the researchers videotaped fish feeding in the Mediterranean off Turkey in two areas – one dominated by tropical rabbitfish and the other dominated by native temperate fish. They were surprised by what they found. Native temperate herbivorous fish actually had higher consumption rates than the tropical rabbitfish. “We did not expect to see that,” Tomas Nash said.

But while native fish targeted only adult macroalgae, the two species of rabbitfish fed complementarily – one targeted the mature kelps while the other fed almost exclusively on emerging algal “recruits,” or juvenile plants.

“The result is that one species denudes the forest and the other prevents it from recovering,” said Tomas Nash, who also has a faculty appointment with the Mediterranean Institute for Advanced Studies in Spain.

A study off Japan by collaborators found that the introduction of tropical species there, including rabbitfish and parrotfish, resulted in the loss of kelp forests and the emergence of non-native corals in as little as 20 years.

In the first paper, the researchers outlined how tropical herbivorous fish primarily along west boundary currents are moving into temperate zones, including South Africa, Brazil, the Gulf of Mexico, Australia and Japan, as well as the Mediterranean. Other areas, including the Pacific Northwest of the United States, have not seen sustained spread of tropical species likely due to prevailing currents and because surface waters are too cold due to seasonal upwelling.

The researchers found algal forests in the waters off Greece had not been severely affected because only the rabbitfish that feeds on adult algae is present and in relatively low densities. They have just begun studies of rabbitfish and chub arrivals in Australia.

“The greatest damage that we documented was off Turkey, which may be serving as the proverbial canary in the coal mine,” Tomas Nash said. “The barrenness of the underwater habitat is unique and quite striking – it is spread over hundreds of kilometers.”

Media Contact: 
Source: 

Fiona Tomas Nash, 541-737-4531; fiona.tomasnash@oregonstate.edu

Multimedia Downloads
Multimedia: 

 

 

 

 

 

 

 

 




Cystos Adrasan 1

Healthy ecosystem

 

 

denuded landscape

Effects of non-native fish

New technology tracks carcinogens as they move through the body

CORVALLIS, Ore. – Researchers for the first time have developed a method to track through the human body the movement of polycyclic aromatic hydrocarbons, or PAHs, as extraordinarily tiny amounts of these potential carcinogens are biologically processed and eliminated.

PAHs, which are the product of the incomplete combustion of carbon, have been a part of everyday human life since cave dwellers first roasted meat on an open fire. More sophisticated forms of exposure now range from smoked cheese to automobile air pollution, cigarettes, a ham sandwich and public drinking water. PAHs are part of the food we eat, the air we breathe and the water we drink.

However, these same compounds have gained increasing interest and scientific study in recent years due to their role as carcinogens. PAHs or PAH mixtures have been named as three of the top 10 chemicals of concern by the Agency for Toxic Substances Disease Registry.

With this new technology, scientists have an opportunity to study, in a way never before possible, potential cancer-causing compounds as they move through the human body. The findings were just published by researchers from Oregon State University and other institutions in Chemical Research in Toxicology, in work supported by the National Institute of Environmental Health Sciences (NIEHS)

The pioneering work has been the focus of Ph.D. research by Erin Madeen at Oregon State, whose studies were supported in part by an award from the Superfund Research Program at NIEHS for her work at Lawrence Livermore National Laboratory.

“We’ve proven that this technology will work, and it’s going to change the way we’re able to study carcinogenic PAHs,” said David Williams, director of the Superfund Research Program at OSU, a professor in the College of Agricultural Sciences and principal investigator with the Linus Pauling Institute.

“Almost everything we know so far about PAH toxicity is based on giving animals high doses of the compounds and then seeing what happens,” Williams said. “No one before this has ever been able to study these probable carcinogens at normal dietary levels and then see how they move through the body and are changed by various biological processes.”

The technology allowing this to happen is a new application of accelerator mass spectrometry, which as a biological tracking tool is extraordinarily more sensitive than something like radioactivity measuring. Scientists can measure PAH levels in blood down to infinitesimal ratios – comparable to a single drop of water in 4,000 Olympic swimming pools, or to a one-inch increment on a 3-billion mile measuring tape.

As a result, microdoses of a compound, even less than one might find in a normal diet or environmental exposure, can be traced as they are processed by humans. The implications are profound.

“Knowing how people metabolize PAHs may verify a number of animal and cell studies, as well as provide a better understanding of how PAHs work, identifying their mechanism or mechanisms of action," said Bill Suk, director of the NIEHS Superfund Research Program.

One PAH compound studied in this research, dibenzo (def,p)-chrysene, is fairly potent and defined as a probable human carcinogen. It was administered to volunteers in the study in a capsule equivalent to the level of PAH found in a 5-ounce serving of smoked meat, which provided about 28 percent of the average daily dietary PAH intake. There was a fairly rapid takeup of the compound, reaching a peak metabolic level within about two hours, and then rapid elimination. The researchers were able to study not only the parent compound but also individual metabolites as it was changed.

“Part of what’s so interesting is that we’re able to administer possible carcinogens to people in scientific research and then study the results,” Williams said. “By conventional scientific ethics, that simply would not be allowed. But from a different perspective, we’re not giving these people toxins, we’re giving them dinner. That’s how much PAHs are a part of our everyday lives, and for once we’re able to study these compounds at normal levels of human exposure.”

What a scientist might see as a carcinogen, in other words, is what most of us would see as a nice grilled steak. There are many unexpected forms of PAH exposure. The compounds are found in polluted air, cigarettes, and smoked food, of course, but also in cereal grains, potatoes and at surprisingly high levels in leafy green vegetables.

“It’s clear from our research that PAHs can be toxic, but it’s also clear that there’s more to the equation than just the source of the PAH,” Williams said. “We get most of the more toxic PAHs from our food, rather than inhalation. And some fairly high doses can come from foods like leafy vegetables that we know to be healthy. That’s why we need a better understanding of what’s going on in the human body as these compounds are processed.”

The Williams-led OSU laboratory is recruiting volunteers for a follow-up study that will also employ smoked salmon as a source of a PAH mixture and relate results to an individual’s genetic makeup.

Some of the early findings from the study actually back up previous research fairly well, Williams said, which was done with high-dose studies in laboratory animals. It’s possible, he said, that exposure to dietary PAHs over a lifetime may turn out to be less of a health risk that previously believed at normal levels of exposure, but more work will need to be done with this technology before such conclusions could be reached.

Collaborators on the study were from the Pacific Northwest National Laboratory, Lawrence Livermore National Laboratory, and the OSU Environmental Health Sciences Center.

“Further development and application of this technology could have a major impact in the arena of human environmental health,” the researchers wrote in their conclusion.

Media Contact: 
Source: 

David Williams, 541-737-3277 or david.williams@oregonstate.edu

Scientists prepare for another wave of tsunami debris, possible invasives

NEWPORT, Ore. – Scientists monitoring incoming tsunami debris were taken aback last spring when some 30 fishing vessels from Japan washed ashore along the Pacific Northwest coast – many of them covered in living organisms indigenous to Asia.

Incidence of wayward skiffs and other tsunami debris subsequently declined sharply over the summer because of seasonal shifts in the winds. Now, those winds and currents have returned to their winter-spring pattern and scientists are expecting more items to wash ashore – even though it is nearing four years since a massive earthquake and tsunami shook Japan.

Blue mussels have been found on literally every boat that has washed ashore and some 200 different species overall have been documented on tsunami debris, according to John Chapman, an Oregon State University marine invasive species specialist at OSU’s Hatfield Marine Science Center.

“The crustaceans and bivalves are of particular concern because they could introduce new diseases, and compete with, displace or otherwise affect our oyster or mussel populations,” Chapman noted.

Just last week, a tote with numerous mussels washed up at Seal Rock – a sign that debris will still be arriving over the next few months. Of particular concern are boats and large objects that wash ashore carrying a variety of living organisms – including some new species that were not aboard the now-infamous dock that landed on Agate Beach near Newport, Ore., in June of 2012.

“We continue to find new organisms that we have never seen before,” Chapman said. “There isn’t as much diversity aboard the Japanese fishing vessels as there was on the dock, but each new species that we haven’t seen before is a cause for concern.

“No one can predict if these new species may gain a foothold in Northwest waters – and what impacts that may have,” he added.

Chapman and OSU colleague Jessica Miller have examined roughly a dozen boats that have washed ashore from the southern Oregon coast to the central Washington coast. Most of them were similar in style – long, narrow skiffs up to 30 feet in length, with no motors. As they drift from Asia to the West Coast of North America, they pick up a variety of organisms along the way.

“We’ve been surprised at the tenacity of some of these coastal Asian organisms that are arriving on the tsunami debris because the middle of the ocean isn’t the most biologically productive place for coastal species,” Miller said.

Among some of the species the Oregon State biologists have encountered over the past year are bat stars, which are sea stars that look like they have bat wings; striped knifejaw, fish that were found alive in at least one boat; and numerous small crustaceans.

Teams of scientists from around the North Pacific region, including Chapman and Miller, have identified more than 165 species that were aboard the original dock, and another 40-50 species that were found on other debris items, including boats. The rate of incoming debris should be slowing, the researchers say, but the arrival of so many boats last spring suggests that the threat is not over.

Invasive marine species are a problem on the West Coast, where they usually are introduced via ballast water from ships. OSU’s Chapman is well aware of the issue; for several years he has studied a parasitic isopod called Griffen’s isopod that was introduced from Asia. Griffen’s isopod infests mud shrimp in estuaries from California to Vancouver Island and is decimating their populations.

The OSU researchers are working with other scientists on the West Coast, who are attempting to genetically identify all of the species arriving on tsunami debris using genomic sampling – work led by Jon Geller of Moss Landing Marine Laboratory. Geller and his students also are collecting samples of marine life in Northwest coastal and estuary communities to look for evidence that non-native species may have established.

“We’re also doing a lot of old-fashioned looking,” Chapman said. “But new species can be difficult to identify if you aren’t searching for them directly in the first place. So we’ve identified three species that are particularly abundant in Asia, appear highly suited for invading the open coast, and would be readily apparent to searchers looking in the right place.”

These species include a hydroid, Eutima; a fly, Telmatogeton; and an amphipod crustacean, Caprella cristibrachium.

Media Contact: 
Source: 

John Chapman, 541-867-0235;

Jessica Miller, 541-867-0381

Multimedia Downloads
Multimedia: 

lincolncntywrms

crate

lincolncrab

ilwacojune1

Study: Could sleeper sharks be preying on protected Steller sea lions?

NEWPORT, Ore. – Pacific sleeper sharks, a large, slow-moving species thought of as primarily a scavenger or predator of fish, may be preying on something a bit larger – protected Steller sea lions in the Gulf of Alaska.

A new study found the first indirect evidence that this cold-blooded shark that can grow to a length of more than 20 feet – longer than a great white shark – may be an opportunistic predator of juvenile Steller sea lions.

Results of the study have just been published in the journal Fishery Bulletin. The findings are important, scientists say, because of management implications for the protected Steller sea lions.

For the past decade, Markus Horning of the Marine Mammal Institute at Oregon State University has led a project in collaboration with Jo-Ann Mellish of the Alaska SeaLife Center to deploy specially designed “life history transmitters” into the abdomens of juvenile Steller sea lions. These buoyant archival tags record data on temperature, light and other properties during the sea lions’ lives and after the animals die the tags float to the surface or fall out ashore and transmit data to researchers via satellite.

From 2005-11, Horning and his colleagues implanted tags into 36 juvenile Steller sea lions and over a period of several years, 17 of the sea lions died. Fifteen transmitters sent data indicating the sea lions had been killed by predation.

“The tags sense light and air to which they are suddenly exposed, and record rapid temperature change,” said Horning, who is in OSU’s Department of Fisheries and Wildlife. “That is an indication that the tag has been ripped out of the body, though we don’t know what the predator is that did this.

“At least three of the deaths were different,” he added. “They recorded abrupt temperature drops, but the tags were still dark and still surrounded by tissue. We surmise that the sea lions were consumed by a cold-blooded predator because the recorded temperatures aligned with the deep waters of the Gulf of Alaska and not the surface waters.

“We know the predator was not a killer whale, for example, because the temperatures would be much higher since they are warm-blooded animals.” Data collected from the transmitters recorded temperatures of 5-8 degrees Celsius.

That leaves a few other suspects, Horning said. However, two known predators of sea lions – great white sharks and salmon sharks – have counter-current heat exchanges in their bodies that make them partially warm-blooded and the tags would have reflected higher temperatures.

By process of elimination, Horning suspects sleeper sharks.

The Oregon State pinniped specialist acknowledges that the evidence for sleeper sharks is indirect and not definitive, thus he is planning to study them more closely beginning in 2015. The number of sleeper sharks killed in Alaska as bycatch ranges from 3,000 to 15,000 annually, indicating there are large numbers of the shark out there. The sleeper sharks caught up in the nets are usually comparatively small; larger sharks are big enough to tear the fishing gear and are rarely landed.

“If sleeper sharks are involved in predation, it creates something of a dilemma,” said Horning, who works out of OSU’s Hatfield Marine Science Center in Newport, Ore. “In recent years, groundfish harvests in the Gulf of Alaska have been limited in some regions to reduce the potential competition for fish that would be preferred food for Steller sea lions.

“By limiting fishing, however, you may be reducing the bycatch that helps keep a possible limit on a potential predator of the sea lions,” he added. “The implication could be profound, and the net effect of such management actions could be the opposite of what was intended.”

Other studies have found remains of Steller sea lions and other marine mammals in the stomachs of sleeper sharks, but those could have been the result of scavenging instead of predation, Horning pointed out.

The western distinct population of Steller sea lions has declined to about 20 percent of the levels they were at prior to 1975.

Media Contact: 
Source: 

Markus Horning, 541-867-0270, markus.horning@oregonstate.edu

Educated community no protection against a poor diet for children

 

CORVALLIS, Ore. – A study of elementary school children in a highly educated community in the Pacific Northwest found that about three fourths of the students had vitamin D levels that were either insufficient or deficient, and they also lacked an adequate intake of other important nutrients.

The findings, reported recently in the Journal of Extension by scientists from the Linus Pauling Institute at Oregon State University, make it clear that nutritional deficiencies can be profound even in communities with a very knowledgeable population and easy access to high quality, affordable food.

Many other studies have found similar concerns in areas with low socioeconomic status, poor food availability, and lower levels of education. This research identified significant nutritional problems in Corvallis, Ore., a university town with many grocery stores, a free bus transit system and some of the highest educational levels in the nation. In Corvallis, 26 percent of residents have completed a graduate degree, which is more than double the national average.

As students grew from younger children into adolescents, the problems only got worse, the research showed. The trend continued toward a diet focused on simple carbohydrates, and low both in fiber and important micronutrients.

“It’s becoming increasingly clear that health and dietary concerns cut across all populations, including comparatively well-educated or affluent groups,” said Gerd Bobe, an assistant professor with the OSU College of Agricultural Sciences and member of the Healthy Youth Program at the Linus Pauling Institute.

“This research also showed nutritional status and dietary choices are getting worse as students become teenagers,” Bobe said. “The foundation for lifelong health is laid in childhood, and puberty is a critical time for growth, brain and bone development. It’s a really bad time to have a bad diet. Since Corvallis is a very educated community with many health-conscious individuals, this is an illustration of just how widespread these problems are.”

The study focused some of its attention on vitamin D, taking blood samples from 71 students at four public elementary schools in Corvallis. They found about 8 percent of students were outright deficient in this vitamin, and about 69 percent were “insufficient,” defined as a level that’s less than ideal for optimal health.

Vitamin D is important for immune function; brain, muscle and bone development and health; and prevention of chronic diseases, including diabetes and cancer. It is often found to be deficient in many temperate zones where people don’t get adequate sun exposure.

The study examined children in two age groups, 5-8 years old and 9-11 years. The older children had even lower vitamin D levels that the younger group, correlated to a lower consumption of dairy products.

Based on their findings, the researchers suggested that educational or outreach programs to improve nutrition understanding are needed in a broad cross section of society, not just low-income or underserved groups.

“Studies show that children and adults both learn best when all their senses are involved, through something like cooking classes combined with nutrition education,” said Simone Frei, manager of the Healthy Youth Program at the Linus Pauling Institute.

“In our classes, youth and families learn about eating plenty of fresh fruits and vegetables, whole grain foods and reducing processed foods,” Frei said. “This is even more effective when combined with growing and harvesting fresh vegetables from the garden.”

This program, among other initiatives, operates a “Chefs in the Garden” summer camp, and data show that 65 percent of participating children increased their vegetable consumption after the camp experience.

Among the other findings of the study:

  • Most of the children reported a diet insufficient in fiber and essential fatty acids;
  • Nearly all children consumed less potassium and more sodium than recommended, a health habit that ultimately can be associated with higher levels of chronic diseases, including heart disease and cancer;
  • Only a single child in the entire study group reported a diet that would provide adequate intake of vitamin E, which is important for neurological development, cognition and anemia prevention.

As a result of the study, educational programs were developed by the Healthy Youth Program at OSU, some of which are available online at http://bit.ly/1ukBNnT

Media Contact: 
Source: 

Gerd Bobe, 541-737-1898

Multimedia Downloads
Multimedia: 

Learning to garden
Learning to garden


A healthy feast
A healthy feast

Rivers recover natural conditions quickly following dam removal

 

The study this story is based on is available online: http://bit.ly/1rdQ4wL

CORVALLIS, Ore. – A study of the removal of two dams in Oregon suggests that rivers can return surprisingly fast to a condition close to their natural state, both physically and biologically, and that the biological recovery might outpace the physical recovery.

The analysis, published by researchers from Oregon State University in the journal PLOS One, examined portions of two rivers – the Calapooia River and Rogue River. It illustrated how rapidly rivers can recover, both from the long-term impact of the dam and from the short-term impact of releasing stored sediment when the dam is removed.

Most dams have decades of accumulated sediment behind them, and a primary concern has been whether the sudden release of all that sediment could cause significant damage to river ecology or infrastructure.

However, this study concluded that the continued presence of a dam on the river constituted more of a sustained and significant alteration of river status than did the sediment pulse caused by dam removal.

“The processes of ecological and physical recovery of river systems following dam removal are important, because thousands of dams are being removed all over the world,” said Desirée Tullos, an associate professor in the OSU Department of Biological and Ecological Engineering.

“Dams are a significant element in our nation’s aging infrastructure,” she said. “In many cases, the dams haven’t been adequately maintained and they are literally falling apart. Depending on the benefits provided by the dam, it’s often cheaper to remove them than to repair them.”

According to the American Society of Civil Engineers, the United States has 84,000 dams with an average age of 52 years. Almost 2,000 are now considered both deficient and “high hazard,” and it would take $21 billion to repair them. Rehabilitating all dams would cost $57 billion. Thus, the removal of older dams that generate only modest benefits is happening at an increasing rate.

In this study, the scientists examined the two rivers both before and after removal of the Brownsville Dam on the Calapooia River and the Savage Rapids Dam on the Rogue River. Within about one year after dam removal, the river ecology at both sites, as assessed by aquatic insect populations, was similar to the conditions upstream where there had been no dam impact.

Recovery of the physical structure of the river took a little longer. Following dam removal, some river pools downstream weren’t as deep as they used to be, some bars became thicker and larger, and the grain size of river beds changed. But those geomorphic changes diminished quickly as periodic floods flushed the river system, scientists said.

Within about two years, surveys indicated that the river was returning to the pre-removal structure, indicating that the impacts of the sediment released with dam removal were temporary and didn’t appear to do any long-term damage.

Instead, it was the presence of the dam that appeared to have the most persistent impact on the river biology and structure – what scientists call a “press” disturbance that will remain in place so long as the dam is there.

This press disturbance of dams can increase water temperatures, change sediment flow, and alter the types of fish, plants and insects that live in portions of rivers.  But the river also recovered rapidly from those impacts once the dam was gone.

It’s likely, the researchers said, that the rapid recovery found at these sites will mirror recovery on rivers with much larger dams, but more studies are needed.

For example, large scale and rapid changes are now taking place on the Elwha River in Washington state, following the largest dam removal project in the world. The ecological recovery there appears to be occurring rapidly as well. In 2014, Chinook salmon were observed in the area formerly occupied by one of the reservoirs, the first salmon to see that spot in 102 years.

“Disturbance is a natural river process,” Tullos said. “In the end, most of these large pulses of sediment aren’t that big of a deal, and there’s often no need to panic. The most surprising finding to us was that indicators of the biological recovery appeared to happen faster than our indicators of the physical recovery.”

The rates of recovery will vary across sites, though. Rivers with steeper gradients, more energetic flow patterns, and non-cohesive sediments will recover more quickly than flatter rivers with cohesive sediments, researchers said.

This research was supported by the Oregon Watershed Enhancement Board, the National Oceanic and Atmospheric Association and the National Marine Fisheries Service. It was a collaboration of researchers from the OSU College of Agricultural Sciences, College of Engineering, and College of Science.

Media Contact: 
Source: 

Desirée Tullos, 541-737-2038

Multimedia Downloads
Multimedia: 

Dam removal

Removing Savage Rapids Dam

Study finds air temperature models poor at predicting stream temps

CORVALLIS, Ore. – Stream temperatures are expected to rise in the future as a result of climate change, but a new study has found that the correlation between air temperature and stream temperature is surprisingly tenuous.

The findings cast doubt on many statistical models using air temperatures to predict future stream temperatures.

Lead author Ivan Arismendi, a stream ecologist at Oregon State University, examined historic stream temperature data over a period of one to four decades from 25 sites in the western United States to see if increases in air temperature during this period could have predicted – through the use of statistical models – the observed stream temperatures.

He discovered that many streams were cooler than the models predicted, while others were warmer. The difference in temperature between the models and actual measurements, however, was staggering – as much as 12 degrees Celsius different in some rivers.

Results of the study have recently been published in the journal Environmental Research Letters. The study involved scientists from Oregon State, the U.S. Forest Service and the U.S. Geological Survey, and was supported by all three organizations, as well as by the National Science Foundation.

“These air-stream temperature models originated as a tool for looking at short-term relationships,” said Arismendi, a researcher in the OSU Department of Fisheries and Wildlife. “The problem is that people are starting to use them for long-term extrapolation. It is unreliable to apply uniform temperature impacts on a regional scale because there are so many micro-climate factors influencing streams on a local basis.”

Sherri Johnson, a U.S. Forest Service research ecologist and co-author on the study, said the findings are important because decisions based on these models may not be accurate. Some states, for example, have projected a major loss of suitable habitat for trout and other species because the models suggest increases in stream temperature commensurate with projected increases in air temperature.

“It just isn’t that simple,” Arismendi said. “Stream temperatures are influenced by riparian shading and in-stream habitat, like side channels. Dams can have an enormous influence, as can groundwater. It is a messy, complex challenge to project stream temperatures into the future.”

What made this study work, the authors say, was evaluating more than two dozen sites that had historic stream temperature data, which can be hard to find. The development about a dozen years ago of data loggers that can be deployed in streams is contributing enormous amounts of new data, but accurate historic records of stream temperatures are sparse.

Researchers at USGS and at sites like the H.J. Andrews Experimental Forest in Oregon, part of the National Science Foundation’s Long-Term Ecological Research program, have compiled stream data for up to 44 years, giving Arismendi and his colleagues enough historical data to conduct the comparative study.

In many of the 25 sites examined in the study, the researchers found that the difference between model-projected stream temperatures and actual stream temperatures was as great as the actual amount of warming projected – 3.0 degrees Celsius, or 5.5 degrees Fahrenheit. And in some cases, the projections were even farther off target.

“The models predictions were poor in summer and winter, and when there are extreme situations,” Arismendi noted. “They were developed to look at Midwest streams and don’t account for the complexity of western streams that are influenced by topography, extensive riparian areas and other factors.”

Increases in air temperatures in the future are still likely to influence stream temperatures, but climate sensitivity of streams “is more complex than what is being realized by using air temperature-based models,” said Mohammad Safeeq, an Oregon State University researcher and co-author on the study.

“The good news is that some of the draconian projections of future stream temperatures may be overstated,” noted Safeeq, who is in OSU’s College of Earth, Ocean, and Atmospheric Sciences. “On the other hand, some may actually be warmer than what air temperature-based models project.”

Not all streams will be affected equally, Johnson said.

“The one constant is that a healthy watershed will be more resilient to climate change than one that isn’t healthy – and that should continue to be the focus of restoration and management efforts,” she noted.

Jason Dunham, an aquatic ecologist with the USGS and co-author on the study, said the study highlights the value of long-term stream temperature records in the Northwest and globally.

“Without a long-term commitment to collecting this kind of data, we won’t have the ability to evaluate existing models as we did in this work,” Dunham said. “Long-term datasets provide vital material for developing better methods for quantifying the effects of climate on our water resources.”

Media Contact: 
Source: 

Ivan Arismendi, 541-750-7443;

Sherri Johnson, 541-758-7771

OSU researchers tagging whales off southern California

NEWPORT, Ore. – Oregon State University researchers are tagging blue and fin whales off the coast of southern California this summer to study their movements, some of which include preferred feeding grounds near areas of heavy ship traffic.

The project, which is being funded by the U.S. Navy, will build on a previous study by OSU researchers that documented the seasonal distribution of blue whales, including their appearance near established shipping lanes off Santa Barbara. That analysis was based on satellite tracking of 171 blue whales for up to 13 months during a 15-year stretch from 1993 to 2008.

It was published last month in the journal PLOS ONE. Since that publication, six major shipping companies voluntarily agreed to slow their ships near Santa Barbara to lessen the chance of striking endangered blue whales, and to reduce pollution.

“No one wants to see whales hit by ships, and it is clear from the analysis that there has been some historic overlap of blue whale feeding areas and shipping lanes,” said Bruce Mate, director of Oregon State University’s Marine Mammal Institute, which is conducting the tagging project. “The goal of the new Navy-funded project is to better understand the seasonal occurrence of blue and fin whales in southern California and determine if that overlap is still taking place for these protected species.”

An OSU team led by Ladd Irvine began tagging the whales last month and thus far has successfully deployed 21 tags. The researchers hope to attach 24 long-term satellite tracking tags – a dozen each for blue whales and fin whales – and another eight more sophisticated tags that will track the whales’ underwater feeding habits. They hope to attach four of these Advanced-Dive-Behavior tags on blue whales and four on fin whales.

OSU’s recently published 15-year analysis was the most comprehensive study of blue whales movements ever conducted. It tracked the movement of blue whales off the West Coast to identify important habitat areas and environmental correlates, and subsequently to understand the timing of their presence near major ports and shipping traffic.

“The main areas that attract blue whales are highly productive, strong upwelling zones that produce large amounts of krill – which is pretty much all that they eat,” said Irvine, who was lead author on the PLOS ONE study. “The whales have to maximize their food intake during the summer before they migrate south for the winter, typically starting in mid-October to mid-November. It appears that two of their main foraging areas are coincidentally crossed by shipping lanes.”

An estimated 2,500 of the world’s 10,000 blue whales spend time in the waters off the West Coast of the Americas and are known as the eastern North Pacific population. Blue whales can grow to the length of a basketball court, weigh as much as 25 large elephants combined, and their mouths could hold 100 people, though their diet is primarily krill – tiny shrimp-like creatures less than two inches in length.

At a distance, fin whales look a lot like blue whales. They are the second largest of the whales and reach 75 feet in length – the size of two buses. The tall, columnar blows of fin whales look much like that of blue whales. Fin whales have a taller, sickle-shaped dorsal fin, a lower right lip that is white, and feed on schooling fish as well as krill.

Media Contact: 
Source: 

Bruce Mate, 541-867-0202; bruce.mate@oregonstate.edu

OSU research helps Chinese crested terns make comeback

CORVALLIS, Ore. – A collaborative project between researchers in Oregon and Asia last year helped establish a new breeding colony for one of the world’s most endangered seabirds – the Chinese crested tern – which then had a global population estimated at fewer than 50 birds.

This summer, at least 43 of the critically endangered birds arrived at the colony on the island of Tiedun Dao in Zhejiang Province, forming at least 20 breeding pairs. By early August, 13 young birds had fledged.

“It is a remarkable success story,” said Dan Roby, a professor of wildlife ecology at Oregon State University, who helped establish the new breeding colony. “The lessons that we learned in Oregon through luring Caspian terns to new breeding colonies away from the Columbia River translated quite well to the Chinese crested terns.”

Once thought to be extinct, there were no recorded sightings of Chinese crested terns from the 1930s until 2000, when a few birds were rediscovered on the Matsu Islands. Until last year, there were only two known breeding colonies for this species of tern – both in island archipelagos close to China’s southeast coast.

Both of these colonies have been susceptible to illegal egg collection for food, as well as to typhoons that can devastate seabird breeding colonies, Roby pointed out. The effort to establish a new colony was the first step toward creating a network of island sanctuaries where Chinese crested terns and other seabird species of conservation concern could raise their young, he added.

To establish a new colony, a project team including students and faculty from OSU’s Department of Fisheries and Wildlife worked with colleagues in China to clear part of Tiedun Dao of brush, then planted 300 tern decoys on the island and used solar-powered recorders to broadcast vocalizations of both Chinese crested terns and greater crested terns, which are more numerous and not endangered.

“When greater crested terns establish a breeding colony, sometimes it lures in Chinese crested terns as well,” Roby said. “We just didn’t expect it to happen so quickly.”

The China project was designed to recapture the success that Roby and the Army Corps of Engineers had in establishing new breeding colonies in Oregon for Caspian terns far away from the Columbia River, where they had been decimating juvenile salmon migrating downstream. They established new colonies in southeast Oregon and successfully lured thousands of birds to the new sites.

The technique of clearing vegetation, planting decoys and luring birds through playback of vocalizations was developed by Stephen Kress of the National Audubon Society.

Even though the new breeding colony for Chinese crested terns was successful, it wasn’t without peril, according to Simba Chan, senior conservation officer of BirdLife International’s Asia Division, who stayed on Tiedun Dao from early May to early August to monitor the colony. During that time, the endangered birds and their chicks endured attempted predation by peregrine falcons, attempted poaching by an egg collector, and three typhoons.

Chan and his colleagues collected a lot of data about the birds’ behavior that will help inform the management of the birds as well as the design of future colonies.

Chinese crested terns are highly efficient at finding and catching forage fish and adept at defending their nest sites during territorial disputes with their neighbors. Crested terns breed in very dense colonies with six to seven nesting pairs per square meter. The decline and near-extinction of Chinese crested terns in the 20th century was likely due to their restricted breeding range and widespread overharvest of seabird eggs.

“Having a new, productive breeding site away from the other two known colonies gives the species a far better chance to recover,” Roby said.

The project was supported by numerous international groups.

Media Contact: 
Source: 

Dan Roby, 541-737-1955; Daniel.roby@oregonstate.edu

Multimedia Downloads
Multimedia: 

terns0965

 

terns0383

First tagging study of Antarctic minke whales shows unique feeding

NEWPORT, Ore. – Scientists for the first time have used tags to track the behavior of Antarctic minke whales and discovered that this smallest of the lunge-feeding whales utilizes the sea ice more than expected and feeds in ways unique from other species.

The study is also important from another standpoint: The researchers were able to acquire significant data on minke whales using non-lethal methods. Minkes have been the subject of lethal sampling by some countries under the label of “scientific whaling.”

Results of the study, which was funded by the National Science Foundation, are being published in the Journal of Experiment Biology.

“We know a lot about the feeding and diving behavior of larger whales, but not as much has been known about minke whales – especially in Antarctica,” said Ari Friedlaender, a principal investigator with the Marine Mammal Institute at Oregon State University and lead author on the study. “They are major krill predators and understanding how and where they feed is important.

“It gives us a better understanding of how changes in sea ice might affect these whales and the Antarctic ecosystem,” he added.

In their study, the researchers used suction cup tags equipped with multiple sensors to track the feeding performance of minke whales in Antarctica. They recorded 2,831 feeding events during 649 foraging dives from the tag records. They discovered that the small size of the minke whales provides them with better maneuverability, which enables them to navigate in and around the ice to locate krill.

Unlike larger whales, however, minke whales are limited by their comparatively small feeding apparatus. In other words, they cannot take in as much krill-filled water as their larger counterparts. Larger baleen whales feed by taking a small number of very large gulps – encompassing from 100 to 150 percent of their body mass.

Minke whales, in contrast, take high numbers of much smaller gulps – no more than 70 percent of their body mass, and often much less, according to Friedlander, an associate professor in the Department of Fisheries and Wildlife who works out of OSU’s Hatfield Marine Science Center in Newport, Ore.

“They compensate by making many more lunges per dive than other whales,” Friedlaender noted. “They are able to do this because their physiology keeps the energy cost of each lunge very low. We documented minke whales that made foraging dives beneath sea ice that included as many as 24 lunges for krill on each dive – the highest feeding rate for any lunge-feeding whale.”

The Antarctic minke whales occupy a unique niche in the ecosystem, the researchers pointed out. Penguins and seals also feed on krill, but the filter-feeding ability of minke whales allows them to consume greater quantities of the small crustaceans during their dives. The key, researchers say, is their ability to utilize dense patches of prey, which the minke whales can do because of their maneuverability.

The average dive of a minke whale was about 18 meters deep and lasted about a minute-and-a-half. However, the researchers documented dives as deep as 105 meters and lasting as long as seven minutes.

“These kinds of data are important to document because we just haven’t known much about minke whales in any region, but particularly in Antarctica,” Friedlaender pointed out. “The logistics of working in a remote environment, in and around the sea ice – and the difficulty of even approaching the whales - has made them a tough species to study.

“The recent advancement of multi-sensor tag technology helped make this possible.”

Other authors on the paper include Jeremy Goldbogen, Stanford University; Doug Nowacek, Andrew Read and David Johnston, Duke University; and Nick Gales, Australian Antarctic Division.

Media Contact: 
Source: 

Ari Friedlaender, 541-867-0202; ari.friedlaender@oregonstate.edu

Multimedia Downloads
Multimedia: 

minke3

 

minke1