OREGON STATE UNIVERSITY

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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.

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Desirée Tullos, 541-737-2038

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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: 
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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.

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

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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.

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

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Few surfers are deterred by ocean bacteria that makes them sick

CORVALLIS, Ore. – Health warnings issued when beaches have high levels of bacteria do not keep many surfers out of the water, according to a new study by Oregon State University.

Nearly three in 10 surfers admit they knowingly surf during health advisories – nearly the same amount that chooses not to surf during periods of elevated bacteria. About 40 percent of surfers said they were unaware if they had ever surfed during an active health advisory.

The data can help public officials better warn surfers of potential health risks, said Anna Harding, co-author of the study and professor in OSU's College of Public Health and Human Sciences.

"Beach advisories for bacteria are not having their intended effect of dissuading surfers,” Harding said. “The lack of awareness about advisories – and willingness to take risks surfing in water that may be contaminated – suggests the need to educate surfers about behaviors that make them vulnerable to illness."

More than 500 surfers from the Pacific Northwest provided information for OSU's study and spanned a wide range of ages, incomes, surfing frequency and other demographics.

Of those surveyed by OSU, nearly 40 percent reported ear infections or discharge at some point during surfing; 30 percent, a sore throat or cough; 16 percent experienced diarrhea; 10 percent, fever; and 7 percent had vomited. Results were consistent across experience levels and were not lessened by showering after surfing.

Surfing during and after rain also led to higher rates of waterborne illnesses. Surfers are attracted to large waves that accompany a storm, but rain can send fecal bacteria from stormwater outfalls into the Pacific Ocean, as well as flush harmful microbes from animal feces present in streams and rivers onto beaches.

Surfers cannot avoid swallowing water – which can include harmful bacteria – during wipeouts, Harding said. They ingest 10 times more ocean water than swimmers, about 170 milliliters a day, or half a can of soda, she added.

Health advisories are posted online and on signs around the West Coast. But not every beach entrance has a warning sign, and many surfers do not notice them, said Dave Stone, co-author of the study and an environmental and molecular toxicology professor in OSU's College of Agricultural Sciences.

Beach sampling by states is intermittent, tends to lag behind current conditions and cannot cover all waters, Stone added.

"The best thing surfers can do is pay attention to the weather and where stormwater outfalls are located," said Stone, a toxicologist with OSU Extension. “They should also bookmark beach advisory websites with the latest information.”

"Surfers can go far in minimizing their exposure to microbes just by choosing when and where to surf," he added.

When an advisory is issued for a particular beach, water contact is discouraged and state websites advise beachgoers to avoid any activities during which they might swallow water, such as swimming, surfing, diving, and kayaking.

Using earplugs during surfing also leads to higher rates of ear infections, OSU researchers found. Generic earplugs tend to let water and bacteria inside the ear, Stone said, and then trap it inside the canal

OSU's study was funded by Oregon Sea Grant and is available online in the Journal of Water and Health.

Source: 

Anna Harding, 541-737-3830

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15-year analysis of blue whale range off California finds conflict with shipping lanes

NEWPORT, Ore. – A comprehensive 15-year analysis of the movements of satellite-tagged blue whales off the West Coast of the United States found that their favored feeding areas are bisected by heavily used shipping lanes, increasing the threat of injury and mortality.

The researchers note that moving the shipping lanes off Los Angeles and San Francisco to slightly different areas – at least, during summer and fall when blue whales are most abundant – could significantly decrease the probability of ships striking the whales. A similar relocation of shipping lanes in the Bay of Fundy off eastern Canada lowered the likelihood of vessels striking endangered right whales an estimated 80 percent.

Results of the study – which was supported by the Office of Naval Research, the National Geographic Society, the National Science Foundation, private gifts to the Oregon State University Marine Mammal Institute and others – are being published this week in the journal PLOS ONE.

The analysis is the most comprehensive study of blue whales movements ever conducted. It was led by researchers at Oregon State University’s Marine Mammal Institute, who 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 Ladd Irvine, a researcher with OSU’s Marine Mammal Institute and 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,” Irvine added.

In their study, the researchers attached transmitters to 171 blue whales off California at different times between 1993 and 2008 and tracked their movements via satellite. Their study looked at seasonal as well as individual differences in whale distribution, documenting a high degree of variability – but also a strong fidelity to the upwelling zones that coincide with ship traffic to and from the major ports of Los Angeles and San Francisco.

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. The blue whale is the largest creature to ever inhabit the Earth, yet little was known about their range or where they went to breed until Oregon State’s Bruce Mate led a series of tracking studies featured in the popular 2009 National Geographic documentary, “Kingdom of the Blue Whale.”

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. The huge whales can travel from the Gulf of Alaska all the way down to an area near the equator known as the Costa Rica Dome.

The majority of the population spends the summer and fall in the waters off the U.S. West Coast, with the areas most heavily used by the tagged whales occurring off California’s Santa Barbara and San Francisco, which puts them in constant peril from ship strikes.

“During one year, while we were filming the documentary, five blue whales were hit off of southern California during a seven-week period,” said Mate, who directs the Marine Mammal Institute at OSU’s Hatfield Marine Science Center in Newport, Ore. “Blue whales may not be as acoustically aware as species that rely on echolocation to find prey and there is some evidence that the location of the engines in the rear of the ship creates something of an acoustic shadow in front of them, making it hard for whales to hear the ship coming.

“Putting some kind of noise deterrent on the ships isn’t really an option, however,” Mate added. “You don’t really want to drive endangered whales out of their prime habitat and best feeding locations.”

Moving the shipping lanes would not be unprecedented, the researchers note. Scientists brought concerns about right whale ship strikes in the Bay of Fundy to the International Maritime Organization, and the industry led the effort to modify shipping lanes in the North Atlantic more than a decade ago.

Daniel Palacios, also a co-author on the paper and a principal investigator with OSU’s Marine Mammal Institute, said vessel traffic between Santa Barbara and Los Angeles moved south of its current location in the past to comply with the California Clear Air Act, but shifted back to its current location after getting an exemption to the legislation.

“It is not often that research results are so applicable to a policy decision.” Palacios said, “It’s not really our place to make management decisions, but we can inform policy-makers and in this case it is pretty straightforward. You will eliminate many of the ship strikes on blue whales by moving the shipping lanes south of the northern Channel Islands.”

The solution for the San Francisco area is similar, the researchers note, though not quite as simple. Three separate shipping lanes are used in the region and all cross through the home range and core areas of blue whales tagged in this study.

“We did find that the northernmost shipping lanes crossed the area that was most heavily used by tagged whales,” Irvine noted. “Restricting use of the northern lane during the summer and fall when more whales are present is one option; another would be to extend one lane further offshore before separating it into different trajectories, minimizing the overlap of the shipping lanes with the areas used by blue whales.”

The National Oceanic and Atmospheric Administration is planning a review of shipping lanes in the southern California area, which will be informed by this study. A variety of stakeholders must be consulted, however, before any changes are implemented.

Other funding sources for this study over the years including the TOPP Program (Tagging of Pacific Pelagics), the OSU Marine Mammal Institute Endowment, the Alfred P. Sloan Foundation, the Packard Foundation, NASA, the U.S. Geological Survey, the National Park Service, U.S. Fish and Wildlife Service and the Smithsonian Institution.

Media Contact: 
Source: 

Ladd Irvine, 541-867-0394, ladd.irvine@oregonstate.edu; Bruce Mate, 541-867-0202, bruce.mate@oregonstate.edu; Daniel Palacios, 541-990-2750, Daniel.Palacios@oregonstate.edu

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Review: Lead ammunition can be deadly, though mitigation may help

CORVALLIS, Ore. – The ingestion of lead ammunition and lead fishing tackle accounts for illness and mortality in more than 120 different species of birds in North America, according to a newly published review of scientific studies on the issue.

What impact that has at the population level for species is less clear, the researchers say, as is how to deal with the growing controversy over the use of lead for hunting and fishing. The lead issue is complex and steps to mitigate the impacts will be challenging – from cost and performance factors to manufacturing output – but they are possible, the authors point out.

“Although lead shot has been banned for waterfowl hunting in the United States since 1991, and in Canada since 1999, exposure to lead remains a problem for many bird species,” said Susan Haig, supervisory wildlife ecologist with the U.S. Geological Survey and lead author on the study. “However, we did find several examples of ways wildlife managers have helped reduce exposure of birds to lead.”

The review of scientific studies, conducted by biologists from several different institutions and agencies, was published in the July edition of the journal The Condor: Ornithological Applications. A companion perspective article, written by Clinton Epps, an associate professor in the Department of Fisheries and Wildlife at Oregon State University, examines the challenges of transitioning to non-lead ammunition.

In their papers, the researchers do not call for any policy changes, but they outline some of the challenges of reducing the use of lead and explore tactics that have been used to reduce lead exposure.

“Shifting to non-lead alternatives is a lot more complicated than some people think,” said Epps, who has hunted for more than 30 years. “Any efforts to shift hunters and fishermen from using lead needs to be well-informed and collaborative. Everyone concerned with this issue must be prepared to invest time, money, and expertise to work not only with hunters and fishermen, but with ammunition and tackle manufacturers.”

Epps has looked at copper bullets as one less-toxic alternative to lead and notes that they generally work well in modern firearms commonly used for big game hunting. However, effective non-lead alternatives have not yet been developed for all types of hunting firearms, he added.

In the review article, the researchers outline the availability of non-lead ammunition in October 2013 in 35 different calibers and 51 rifle-cartridge configurations at three major online retailers. Of the non-lead options sold by those retailers, only a small proportion was actually in stock: Cabela’s had non-lead ammunition in 18 percent of available sizes; Cheaper Than Dirt, 27 percent; and Bass Pro Shops, 10 percent.

“Non-lead bullets can be difficult to find in all calibers needed, but availability is improving,” Epps said. “Premium quality hunting ammunition costs about the same for lead-based and non-lead options, but I see a lot of people using the cheaper options, which invariably contain lead, so cost may be an issue – particularly for high-volume users.”

The physical properties of lead – including high density, low melting point, malleability and resistance to corrosion – have made it popular in the manufacturing of ammunition and fishing sinkers. However, many birds are sensitive to lead exposure, affecting the structure and function of kidneys, bones, the central nervous system and the blood system. Impacts range from lethargy and anorexia, to reproductive issues and death.

In their review, the researchers noted that lead has widely varying impacts.

  • One study of common loon carcasses found across six New England states found that about 23 percent (118 of 522) of the deaths were caused by ingestion of lead fishing tackle and ammunition;
  • California condors are extremely susceptible to lead poisoning and suffer significant mortality, yet a related species known as turkey vultures can survive with greater and longer exposure to lead;
  • Few studies have been done on population-level impacts of lead with the most complete studies conducted on waterfowl, where deaths from lead poisoning are estimated to be 2-3 percent overall, and 4 percent in mallard ducks.

A survey by the U.S. Geological Survey in 2013 found that 69,000 metric tons (a metric ton is about 2,204 pounds) of lead were used in the production of ammunition in the United States in one year. Annual estimates of lead fishing weights sold in the U.S. equal 3,977 metric tons.

Birds and other animals ingest lead in different ways, according to Haig. Loons, for example, were found to have swallowed lead sinkers and jigs, perhaps mistaking them for prey. Scavengers including condors and eagles often feed on carcasses of animals killed by hunters and cannot avoid incidental lead ingestion.

“Some birds use lead pellets or fragments as grit to aid in digestion after consuming it at hunting areas or shooting ranges,” said Haig, who is a courtesy professor of wildlife ecology at OSU. “Another potentially important lead source is recreational shooting of ground squirrels, which leaves lead-laced carcasses available to be eaten by golden eagles, Swainson’s hawks and other birds of prey.

“We found one estimate that more than 1.1 million ground squirrels were shot in one state during a one-year period,” she added. “It would be helpful to better understand what kinds of risk this poses to raptor scavengers.”

The review outlines some steps to reduce lead exposure to birds, including redistributing shot in the surface soil by cultivating sediments; raising water levels in wetlands to reduce access by feeding birds; and providing alternative uncontaminated food sources.

“Managers have found a number of ways to reduce the risk of lead exposure to birds while preserving the important role hunting plays in wildlife conservation,” Haig said.

One example cited involved Arizona Game and Fish working with other groups in that state on a voluntary approach to the issue.

“They formed a coalition to educate hunters about the negative effects of lead,” Haig pointed out. “The result was more than 80 percent compliance with voluntary non-lead ammunition use among hunters on the Kaibab Plateau and no birds were found with lead poisoning the following year.”

Other authors on the review include Jesse D’Elia, U.S. Fish and Wildlife Service and OSU Department of Fisheries and Wildlife; Collin Eagles-Smith, U.S. Geological Survey and OSU Fisheries and Wildlife; Garth Herring, U.S. Geological Survey; Jeanne M. Fair, Los Alamos National Laboratory; Jennifer Gervais, Oregon Wildlife Institute and OSU Fisheries and Wildlife; James W. Rivers, OSU Department of Forest Ecosystems and Society; and John H. Schulz, University of Missouri.

Media Contact: 
Source: 

Susan Haig, 541-750-0981, susan_haig@usgs.gov; Clint Epps, 541-737-2478, Clinton.epps@oregonstate.edu

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Figure 2 Magpie on carcass
magpie feedng on a carcass

Oregon honeybee losses continue at economically unsustainable rate, OSU survey finds

CORVALLIS, Ore. – More than one in five commercial honeybee hives in Oregon did not survive last winter, continuing a financially challenging trend for professional beekeepers.

Between Oct. 1 and March 31, Oregon beekeepers reported a 21.1 percent loss in colonies of the crucial crop pollinators, according to a survey by Oregon State University. The latest figures are a slight improvement over the state's average annual loss of 22 percent over the past six years.

Nationally, commercial beekeepers reported a 23.2 percent decline last winter, according to a survey by the Bee Informed Partnership, a countrywide collaboration among research labs focusing on honeybee declines. An average of about 30 percent of colonies nationwide has died each winter over the past decade.

"These are challenging times for beekeeping and we have reason to be alarmed," said Ramesh Sagili, an entomologist with Oregon State University's College of Agricultural Sciences who has been conducting honeybee colony loss surveys for the past five years. "While 10-15 percent loss of colonies is considered acceptable, current rates of decline could drive professional beekeepers out of business."

To replace lost colonies, beekeepers must split healthy hives of 50,000 bees or more – a process that takes months and adds substantial costs for labor, new queens and equipment. However, as these lost colonies are replaced, there is not a drop in the total number of hives each year, according to Sagili.

The United States is home to 2.6 million managed honey bee colonies, according to the Bee Informed Partnership.

The U.S. Department of Agriculture credits honeybees with pollinating more than $15 billion worth of crops in the U.S., including pears, blueberries, cherries, apples, and vegetable seeds such as broccoli, mustard, carrots and onions. Many nut trees also rely on bees for pollination, including nearly 900,000 acres of almond trees in California, according to the USDA.

Bee colonies are in significant decline for a variety of reasons, according to Sagili. He said these include Varroa mites, which transmit viral diseases to bees; poor nutrition from a restricted diet resulting from large-scale monocropping; and exposure to pesticides when bees are foraging for nectar and pollen.

"We wish there was an easy answer," said Sagili, who is also a honeybee expert with the OSU Extension Service. “Each of these factors add stress to the bees and compromise their immune systems.”

OSU is home to the Honey Bee Lab, which tests beekeepers' honeybees for mites, diseases and protein levels for a small fee. The lab is estimated to save Oregon's beekeepers about $1.4 million a year in reduced costs for medications, according to Sagili.

More information on the nationwide survey of 2013-14 honeybee colony losses is at http://beeinformed.org/2014/05/colony-loss-2013-2014. Sagili and entomologist Dewey Caron are also co-authors of the nationwide survey; Caron helped conduct OSU's survey and process data.

Source: 

Ramesh Sagili, 541-737-5460

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OSU bee expert Ramesh Sagili

Oregon State University entomologist Ramesh Sagili blows smoke in a hive to calm bees. (Photo by Lynn Ketchum.)

ODFW, OSU to survey hunters about use of lead ammunition

CORVALLIS, Ore. – The Oregon Department of Fish and Wildlife and Oregon State University are collaborating on an effort to survey Oregon hunters about their use and knowledge of lead ammunition.

The random sample of 4,200 Oregon hunters will begin later this month and those selected should receive a letter from ODFW within the next two weeks. Oregon has approximately 250,000 hunters and the survey will include hunters from each geographic region of the state.

The use of lead ammunition has become a national issue because of impacts to wildlife and human health concerns, according to Ron Anglin, ODFW Wildlife Division administrator. Last year, California passed a law banning the use of lead ammunition for all hunting in the state beginning in 2019; other states have adopted voluntary measures encouraging the use of ammunition made from alternative compounds.

“There is no proposal to ban or limit use of lead ammunition in Oregon, but developments outside of Oregon could affect the use of lead ammunition within the state,” Anglin said. “The Environmental Protection Agency was petitioned to ban the use of lead in ammunition on a nationwide basis and there is the potential of condors being restored in northern California.”

The California legislature passed a law banning lead ammunition to protect endangered California condors, according to Dana Sanchez, an OSU Extension wildlife specialist and one of the project leaders. Condors can become ill after scavenging on animals that have been killed by lead bullets. The birds ingest lead fragments and can become sick or die, she said.

“Historically, Oregon has had condors, though none are known to live here now,” Sanchez pointed out. “However, there are efforts to re-establish populations in northern California and if they are successful, it is only a matter of time before condors begin frequenting the southern portions of Oregon.

“Once condors appear in Oregon, they would be subject to federal protection under the Endangered Species Act,” she added.

Sanchez said some conservation organizations in the state are monitoring lead levels in birds of prey brought into wildlife rehabilitation centers. There is increasing concern that lead exposure may be causing impacts to raptors and eagles in some areas, she said.

“This could lead to an initiative or other efforts to eliminate or restrict the use of lead ammunition,” Sanchez said.

The survey was developed by the OSU Survey Research Center, which will collect the data for ODFW and the OSU Wildlife Extension program. Survey results will be used to inform discussions among agencies, groups and others about any potential restrictions in the use of lead ammunition.

The purpose of the survey, Anglin said, is to gather information from the group of stakeholders who would be most affected by any restrictions on lead ammunition – Oregon hunters.

“Ideally, we would like to survey all Oregon hunters, but that is expensive,” Anglin said. “However, by selecting a random sample of hunters from regions across the state, we should get a clear picture of how Oregon hunters feel about lead ammunition and possible alternatives.”

Persons not chosen for the survey are welcome to provide comments on lead ammunition directly to the Oregon Department of Fish & Wildlife at a special email address: ODFW.wildlifeinfo@state.or.us

Anglin said the ODFW/OSU project team plans to conduct a similar survey of non-hunting Oregonians in the future.

Media Contact: 
Source: 

Ron Anglin, 503-947-6301; ODFW.wildlifeinfo@state.or.us; Dana Sanchez, 541-737-6003; dana.sanchez@oregonstate.edu