OREGON STATE UNIVERSITY

marine science and the coast

Marine Biologist to Give Lecture Friday at OSU

CORVALLIS, Ore. – Marine biologist Boris Worm, from Dalhousie University in Halifax, Nova Scotia, will give a free public lecture this Friday, April 11, at Oregon State University beginning at 4 p.m. in Gilfillan Auditorium.

His talk, “Ecosystem Consequences of Fishing Large Marine Predators,” is free and open to the public.

In his talk, he will discuss conservation concerns that arise from declining numbers of large predators, including some tuna and billfishes, sharks and turtles. The decline, and potential extinction of such species, can trigger cascading effects on the ecosystem, he says.

Worm is an expert on ocean biodiversity and the effects of fishing on the marine ecosystem. He has documented the effect of over-fishing at both the local and global scales, and is studying the consequences of changes in marine biodiversity.

Among his research projects is an effort to document large-scale patterns of species diversity in the open ocean. He also is working to document species’ response to habitat change and fishing over the last 50 years.

 

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Andreas Schmittner,
541-737-9952

Latest Earthquake Swarm off Coast Puzzles Scientists

NEWPORT, Ore. – Scientists at Oregon State University’s Hatfield Marine Science Center have recorded more than 600 earthquakes in the last 10 days off the central Oregon coast in an area not typically known for a high degree of seismic activity.

This earthquake “swarm” is unique, according to OSU marine geologist Robert Dziak, because it is occurring within the middle of the Juan de Fuca plate – away from the major, regional tectonic boundaries.

“In the 17 years we’ve been monitoring the ocean through hydrophone recordings, we’ve never seen a swarm of earthquakes in an area such as this,” Dziak said. “We’re not certain what it means. But we hope to have a ship divert to the site and take some water samples that may help us learn more.” The water samples may indicate whether the process causing the earthquakes is tectonic or hydrothermal, he added.

At least three of the earthquakes have been of a magnitude of 5.0 or higher, Dziak said, which also is unusual. On Monday (April 7), the largest event took place, which was a 5.4 quake. Seismic activity has continued through the week and a 5.0 tremor hit on Thursday. Numerous small quakes have continued in between the periodic larger events.

Few, if any, of these earthquakes would be felt on shore, Dziak said, because they originate offshore and deep within the ocean.

The earthquakes are located about 150 nautical miles southwest of Newport, Ore., in a basin between two subsurface “faulted” geologic features rising out of the deep abyssal sediments. The hill closest to the swarm location appears to be on a curved structure edging out in a northwestern direction from the Blanco Transform Fault toward the Juan de Fuca ridge, Dziak said.

Analysis of seismic “decay” rates, which look at the decreasing intensity of the tremors as they radiate outward, suggest that the earthquakes are not the usual sequence of a primary event followed by a series of aftershocks, Dziak said.

“Some process going on down there is sustaining a high stress rate in the crust,” he pointed out.

Dziak and his colleagues are monitoring the earthquakes through a system of hydrophones located on the ocean floor. The network – called the Sound Surveillance System, or SOSUS – was used during the decades of the Cold War to monitor submarine activity in the northern Pacific Ocean. As the Cold War ebbed, these and other unique military assets were offered to civilian researchers performing environmental studies, Dziak said.

Hatfield Marine Science Center researchers also have created their own portable hydrophones, which Dziak has deployed in Antarctica to listen for seismic activity in that region. The sensitive hydrophones also have recorded a symphony of sounds revealing not only undersea earthquakes, but the movement of massive icebergs, and vocalizations of whales, penguins, elephant seals and other marine species.

This isn’t the first time the researchers have recorded earthquake swarms off the Oregon coast, Dziak said. In 2005, they recorded thousands of small quakes within a couple of weeks along the Juan de Fuca Ridge northwest of Astoria. Those earthquakes were smaller, he pointed out, and located along the tectonic plate boundary.

This is the eighth such swarm over the past dozen years, Dziak said, and the first seven were likely because of volcanic activity on the Juan de Fuca ridge. The plate doesn't move in a continuous manner and some parts move faster than others. Movement generally occurs when magma is injected into the ocean crust and pushes the plates apart.

“When it does, these swarms occur and sometimes lava breaks through onto the seafloor,” Dziak pointed out. “Usually, the plate moves at about the rate a fingernail might grow – say three centimeters a year. But when these swarms take place, the movement may be more like a meter in a two-week period."

But this eighth swarm may be different.

“The fact that it’s taking place in the middle of the plate, and not a boundary, is puzzling,” Dziak admitted. “It’s something worth keeping an eye on.”

 

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Bob Dziak,
541-867-0175

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Earthquake Swarm

This earthquake swarm (with red, yellow, brown, purple dots representing different days) is located on a basin between two faulted basement highs that rise above the surrounding, deep abyssal sediments. The swarm, located using the SOSUS hydrophone arrays, has produced more than 600 earthquakes in the past 10 days. (image courtesy of Hatfield Marine Science Center)

New Study Finds Increasing Acidification of Pacific Ocean’s Continental Shelf

CORVALLIS, Ore. – An international team of scientists surveying the waters of the continental shelf off the West Coast of North America has discovered for the first time high levels of acidified ocean water within 20 miles of the shoreline, raising concern for marine ecosystems from Canada to Mexico.

Researchers aboard the Wecoma, an Oregon State University research vessel, also discovered that this corrosive, acidified water that is being “upwelled” seasonally from the deeper ocean is probably 50 years old, suggesting that future ocean acidification levels will increase since atmospheric levels of carbon dioxide have increased rapidly over the past half century.

Results of the study were published this week in Science Express.

“When the upwelled water was last at the surface, it was exposed to an atmosphere with much lower CO2 (carbon dioxide) levels than today’s,” pointed out Burke Hales, an associate professor in the College of Oceanic and Atmospheric Sciences at Oregon State University and an author on the Science study. “The water that will upwell off the coast in future years already is making its undersea trek toward us, with ever-increasing levels of carbon dioxide and acidity.

“The coastal ocean acidification train has left the station,” Hales added, “and there not much we can do to derail it.”

Scientists have become increasingly concerned about ocean acidification in recent years, as the world’s oceans absorb growing levels of carbon dioxide from the atmosphere. When that CO2 mixes into the ocean water, it forms carbonic acid that has a corrosive effect on aragonite – the calcium carbonate mineral that forms the shells of many marine creatures.

Certain species of phytoplankton and zooplankton, which are critical to the marine food web, may also be susceptible, the scientists point out, although other species of open-ocean phytoplankton have calcite shells that are not as sensitive.

“There is much research that needs to be done about the biological implications of ocean acidification,” Hales said. “We now have a fairly good idea of how the chemistry works.”

Increasing levels of carbon dioxide in the atmosphere are a product of the industrial revolution and consumption of fossil fuels. Fifty years ago, atmospheric CO2 levels were roughly 310 parts per million – the highest level to that point that the Earth has experienced in the last million years, according to analyses of gas trapped in ice cores and other research.

During the past 50 years, atmospheric CO2 levels have gradually increased to a level of about 380 parts per million.

These atmospheric CO2 levels form the beginning baseline for carbon levels in ocean water. As water moves away from the surface toward upwelling areas, respiration increases the CO2 and nutrient levels of the water. As that nutrient-rich water is upwelled, it triggers additional phytoplankton blooms that continue the process.

There is a strong correlation between recent hypoxia events off the Northwest coast and increasing acidification, Hales said.

“The hypoxia is caused by persistent upwelling that produces an over-abundance of phytoplankton,” Hales pointed out. “When the system works, the upwelling winds subside for a day or two every couple of weeks in what we call a ‘relaxation event’ that allows that buildup of decomposing organic matter to be washed out to the deep ocean.

“But in recent years, especially in 2002 and 2006, there were few if any of these relaxation breaks in the upwelling and the phytoplankton blooms were enormous,” Hales added. “When the material produced by these blooms decomposes, it puts more CO2 into the system and increases the acidification.”

The research team used OSU’s R/V Wecoma to sample water off the coast from British Columbia to Mexico. The researchers found that the 50-year-old upwelled water had CO2 levels of 900 to 1,000 parts per million, making it “right on the edge of solubility” for calcium carbonate-shelled aragonites, Hales said.

“If we’re right on the edge now based on a starting point of 310 parts per million,” Hales said, “we may have to assume that CO2 levels will gradually increase through the next half century as the water that originally was exposed to increasing levels of atmospheric carbon dioxide is cycled through the system. Whether those elevated levels of carbon dioxide tip the scale for aragonites remains to be seen.

“But if we somehow got our atmospheric CO2 level to immediately quit increasing,” Hales added, “we’d still have increasingly acidified ocean water to contend with over the next 50 years.”

Hales says it is too early to predict the biological response to increasing ocean acidification off North America’s West Coast. There already is a huge seasonal variation in the ocean acidity based on phytoplankton blooms, upwelling patterns, water movement and natural terrain. Upwelled water can be pushed all the way onto shore, he said, and barnacles, clams and other aragonites have likely already been exposed to corrosive waters for a period of time.

They may be adapting, he said, or they may already be suffering consequences that scientists have not yet determined.

“You can’t just splash some acid on a clamshell and replicate the range of conditions the Pacific Ocean presents,” Hales said. “This points out the need for cross-disciplinary research. Luckily, we have a fantastic laboratory right off the central Oregon coast that will allow us to look at the implications of ocean acidification.”

The study, funded by the National Oceanic and Atmospheric Administration (NOAA) and the National Aeronautics and Space Administration (NASA), was the first in a planned series of biennial observations of the carbon cycle along the West Coast of the continent. In addition to Hales, principal investigators for the study included Richard A. Feely and Christopher Sabine of the NOAA Pacific Marine Environmental Laboratory; J. Martin Hernandez-Ayon, the University of Baja California in Mexico; and Debby Ianson, of Fisheries and Oceans Canada, Sidney, B.C.

 

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Burke Hales,
541-737-8121

New Mechanism Identified for Action of Possible Carcinogen

CORVALLIS, Ore. – Toxicologists at Oregon State University have identified a new biological mechanism by which a possible carcinogen – a chemical compound that’s widely used in everything from food wrappings to stain-resistant clothing – might increase cancer risk.

The findings were just reported in Environmental Health Perspectives, and relate to perfluorooctanoic acid, or PFOA. Commonly used for decades in many industrial processes, PFOA tends to persist in the environment and can be easily found in the blood of humans or many other animals all over the world.

The EPA is studying concerns about its possible role in developmental toxicity, cancer and other issues. Although in 2006 an EPA science advisory board voted to approve a recommendation that PFOA should be considered a “likely carcinogen,” the agency has made no final conclusions about its safety.

The new OSU study, done at the Sinnhuber Aquatic Research Laboratory with rainbow trout, concluded that PFOA significantly increased the incidence of liver tumors in a manner similar to the natural hormone estrogen – a very different mechanism than the way it had been shown to cause cancer in rodents.

“Laboratory rodents make very good animal models for many cancer studies, but this may not be one of them,” said Abby Benninghoff, a toxicologist with the OSU Department of Environmental and Molecular Toxicology and the Linus Pauling Institute . “The response of rodents and humans to PFOA exposure is most likely not the same. We have reason to believe that trout, which have been used to study cancer for 40 years, may react to PFOA exposure much more like humans do, and therefore provide more useful results.”

In rodents, Benninghoff said, exposure to high levels of PFOA causes a proliferation of “peroxisomes,” which are a part of normal cells that are involved in fat metabolism. Too much activity in these peroxisomes can increase oxidative stress, produce DNA damage and ultimately lead to cancer, researchers believe.

However, this “peroxisome proliferation” is much less of an issue with humans – or trout – perhaps because both humans and trout have fewer receptors that turn on the process of peroxisome proliferation. Because of that, it has been difficult to extrapolate to humans the findings about PFOA that were made with rodents.

By using microarrays that were able to study hundreds of genes in rainbow trout, scientists at OSU were able to identify a different way in which PFOA might cause cancer – it appears to mimic the action of the natural hormone estrogen. The researchers called it a “novel mechanism of carcinogenicity” for this chemical that merits further study.

In humans, several cancers have been linked to estrogen levels, including breast, uterine and ovarian cancer. Some cancer drugs are effective by blocking estrogen. Trout, as well as humans, are very sensitive to tumor promotion by estrogenic compounds.

“This does not, in itself, show that PFOA is a human carcinogen,” Benninghoff said. “However, it gives us an alternative way to understand how it might have those effects, and will provide direction for future research.”

PFOA is a member of a class of perfluorinated compounds that are widely used in many consumer products, such as lubricants, textile coatings, food wrappings, flame retardants, and other applications. PFOA has unusual chemical stability and tends to be found widely in animals, water supplies, and other areas. Some perfluorinated chemicals have been voluntarily removed from the market by manufacturers, but others – including PFOA – are still widely used.

 

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Abby Benninghoff,
541-737-1779

Wright Named to Ocean Studies Board

CORVALLIS, Ore. - Dawn Wright, a professor of geography and oceanography at Oregon State University, has been appointed to the Ocean Studies Board of the National Academies.

The Ocean Studies Board advises the federal government on issues of ocean science, ocean policies and ocean infrastructure needed to understand and protect coastal and marine environments and resources.

Wright does research and analysis in such fields as benthic terrain and habitat characterization, tectonics of mid-ocean ridges, high-resolution bathymetry, underwater videography/photography, and geographic information science. She has served on several other committees of the National Research Council.

Two other OSU scientists, Anne Trehu and Rob Holman, professors of marine geology and geophysics, are also members of the Ocean Studies Board. Both are in OSU’s College of Oceanic and Atmospheric Sciences.

 

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Susan Roberts,
Ocean Studies Board, 202-334-2714

New Studies Highlight Concern over Rising Jellyfish Populations

CORVALLIS, Ore. – Jellyfish populations appear to be increasing along the West Coast and in the Bering Sea and scientists studying the phenomenon are concerned because jellyfish may feed on the same plankton species targeted by herring, sardines and anchovies, juveniles salmon and other fishes.

Compounding the situation, the scientists say, is that there are few predators for adult jellyfish.

“A few birds and fish will eat the jellies in their larval or juvenile stages,” said Richard D. Brodeur, a NOAA biologist and adjunct professor in the College of Oceanic and Atmospheric Sciences at Oregon State University. “But once the medusae reach a certain size, not much eats them.”

Newly published studies by Brodeur, OSU oceanographer Lorenzo Ciannelli and others are looking at the link between climate change and jellyfish populations and they have found this relationship is complex. The prevailing school of thought has been that as ocean waters warm, jellyfish populations will increase. But they have discovered that food sources, reproduction dynamics and ocean currents all play a role in jellyfish populations.

In a paper just published in Progress in Oceanography, the scientists describe a steep increase in jellyfish populations in the Bering Sea through the 1990s, peaking in the summer of 2000. But during the years of 2001 through 2005, when scientists recorded some of the warmest temperatures ever in the Bering Sea, jellyfish populations declined.

“They were still well ahead of their historic averages for that region,” said Ciannelli, an assistant professor in OSU’s College of Oceanic and Atmospheric Sciences. “But clearly jellyfish populations are not merely a function of water temperature.”

One key to learning more about jellyfish expansion has been Ciannelli’s work looking into the organisms’ complex life cycle. Adult males release their sperm into the water column and fertilize the eggs that female adults have released. From each fertilized egg, a larva is produced that attaches itself to a rock or some other solid surface and produces a polyp. These polyps reproduce asexually and eventually the young medusae detach themselves and begin the life cycle anew.

The researchers’ preliminary findings suggest that warmer ocean waters may enhance the stage where polyps transform into colonies, but that hypothesis is based on lab work, not field research. The reason, Ciannelli says, is that polyps are notoriously difficult to locate because of their small size.

“We think that higher temperatures lead to a higher metabolic rate and faster division of cells,” he said. “It accelerates the whole system. But finding polyps in the Bering Sea is like trying to do research on the dark side of the moon.”

Ciannelli and his colleagues are funded by the National Science Foundation to better understand how these polyps are distributed. One hypothesis is that there is a single unique source that produces the small jellyfish in the Bering Sea and their expansion is a product of currents. An alternative theory is that the jellyfish are using pockets of warm water to establish new colonies, which would be consistent with global warming scenarios, he said.

“What we’re trying to figure out is where the energy of the food web is going,” Ciannelli pointed out. “If it is going to the jellyfish, which are eating the plankton, it creates an overall sink because they have few predators. It is diverting the energy of the ocean from the pelagic to the benthic system.”

Scientists have begun looking more closely at food sources for jellyfish off the West Coast of the United States and their findings are surprising. In a paper published in the April 2008 issue of the Marine Ecology Progress Series, a team of scientists including Brodeur quantified diet and predation rates for large jellyfish from an upwelling region in the northern California Current. They found that in an area north of Cape Blanco, Ore., abundant populations of jellyfish ate an average of one-third of all the euphausiid – a type of zooplankton – eggs available each day. Consumption of other taxa reached 10 to 12 percent of the standing stocks.

On the other hand, copepods, important components of the marine food web, were consumed at relatively low levels – less than 1 percent a day. Lead author on that study was Cynthia L. Suchman, who conducted her research out of OSU’s Hatfield Marine Science Center Hatfield Marine Science Center in Newport, Ore., where Brodeur works.

Few scientists are conducting long-term jellyfish studies and the authors suggest that zooplankton studies and predation impacts by jellyfish should be incorporated into long-term studies and ecosystem models. “Unfortunately,” Brodeur said, “there hasn’t been a great deal of funding for jellyfish studies, so we don’t know as much as we should about their impact.”

Trawl surveys by Brodeur and his colleagues found that the spatial overlap between jellyfish and most pelagic fishes, including salmon, was relatively small. But in a forthcoming article in Marine Biology, the researchers point out that the overlap with “planktivorous” fishes that consume copepods and euphausiid eggs – including Pacific sardines, the northern anchovy, Pacific saury, and Pacific herring – was considerable. These prey species also are critical to the diets of salmon and other species in the ocean.

“We’ve been collecting data now for about nine years and it appears, at least on a preliminary basis, that when cold water regimes are prevalent, jellyfish numbers increase,” Brodeur said. “During the warmer years, when food sources are scarcer, there may be fewer jellyfish, but they grow quickly – whether because of elevated metabolic rates or less competition, we don’t know.”

This summer Brodeur will be involved in a series of cruises off the Oregon coast to sample jellyfish populations and see what effect this year’s cold-water La Niña phenomenon may have had.

“It won’t be a good sign for the ecosystem if we get a lot of jellies out there,” he said.

Their research has been supported by the National Science Foundation, NOAA and the National Marine Fisheries Service.

 

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Ric Brodeur,
541-867-0336

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Chrysaora melanaster

Crabbers collaborate with OSU researchers to monitor ocean temperature, hypoxia

CORVALLIS, Ore. – In a unique, symbiotic relationship, Oregon crabbers are working with Oregon State University researchers funded by Oregon Sea Grant to use their crab pots as underwater monitoring stations where data collectors attached to the pots gather vital oceanographic information.

This information might help crabbers more effectively locate their catch while helping scientists provide answers to challenging research questions, such as why and when hypoxia zones form in coastal waters.

Historically, some fishers say they have been wary of researchers for fear that the data gathered would be used to close fisheries or restrict catches and seasons. Likewise, some scientists have been skeptical of the quality of data collected using research technologies in the hands of fishers.

But this project, and other shared research efforts at OSU, demonstrates that fisher-researcher collaboration can work very well, collecting robust data, reducing research costs and helping better understand Oregon’s most valuable fishery: Dungeness crab.

“It’s taken some time to develop trust on both sides, but we’ve figured out that engaging the fishermen actually improves the data,” said Michael Harte, a professor in the OSU College of Oceanic and Atmospheric Sciences and director of the Marine Resource Management Program. “This is fantastic for us. It would cost many thousands of dollars to deploy a single scientific buoy, but by working with the crab fishermen, we can deploy fixed buoys for about $100 each (the cost of the device).”

Because crab pots are positioned using GPS and distributed throughout much of Oregon’s coastal ocean, data can be gathered from a much broader geographical range than using high tech ocean observing methods, such as buoys, towed platforms, or autonomous underwater gliders, which are expensive to purchase and operate.

The temperature data collectors attached to the crab pots are each about the size of a quarter and record temperature data every 10 minutes during the nine-month crabbing season. The information is then scanned and uploaded to computers for analysis and evaluation by project participants.

The OSU researchers, led by oceanographer Kipp Shearman, are working with 10 Oregon crabbers, attaching sensors to about 60 crab pots deployed between Port Orford in the south to Astoria in the north. Most commercial crabbers use between 300 and 800 pots, so the OSU scientists are able to select the locations where they want their sensors deployed.

“One real benefit is that by using the crab pots, we’re increasing both the temporal and spatial resolution of the data,” said Jeremy Childress, an OSU graduate student in Marine Resource Management who is working with Shearman and Harte. “We’re also utilizing the local knowledge of fishers to help direct our research, which is very helpful.”

Al Pazar, a crab fisherman who lives in Florence and fishes out of Newport, said helping OSU researchers collect data is his way of giving back to an industry that’s provided him with a solid livelihood for many years.

“Fishing’s been very good to me, and I’m happy to give something back,” Pazar said. “I love working with OSU, and Sea Grant in particular has helped establish a good connection between Oregon’s fishing industry and academia. The data gathering we do might help answer some important questions. It’s a no-brainer to utilize the local volunteers from the fishing fleets and their gear.”

Childress said that bringing people together who’ve traditionally not worked together is “the really the exciting part.” He credits former OSU graduate student Susan Holmes, who expanded statewide the project started by Shearman off Newport with seed funding from Oregon Sea Grant.

Because of the success of the temperature sensors, Childress and Shearman have developed a larger device that can record both temperature and dissolved oxygen levels in the water near the crab pots. This information could help scientists better understand and predict hypoxia, a lack of oxygen in the water that causes massive die-offs of organisms, including crab, in areas sometimes called “dead zones.”

Although off-the-shelf oxygen sensors are available, Childress is able to build a custom made sensor for about one-third the cost of the others.

“No oxygen means dead crabs or no crab, so the crab fishermen are happy to work with us,” Harte said. “They and their crab pots are going to be out there anyway, and we don’t need huge research grants to tap into this ready-made ocean observing system.”

Harte said he and his colleagues are fortunate to have had Oregon Sea Grant funding the project for two years.

“Sea Grant has been visionary enough to realize this is a great way to engage fishermen in science,” Harte said. “So we’re learning that scientists and fishermen, working together, can collect valid scientific data in a robust way using a relatively inexpensive system that improves our understanding of the ocean. Everybody wins.”

 

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Kipp Shearman, 541-737-1866

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Crab Pot Sensor

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Crab Pot Sensor

HMSC to Host Forum this September on Offshore Aquaculture in the Pacific Northwest

CORVALLIS, Ore. – Oregon State University’s Hatfield Marine Science Center will host a two-day forum in September that will explore the potential challenges and opportunities of developing offshore aquaculture programs in the Pacific Northwest.

Sponsored by numerous federal and state agencies, as well as private foundations, the forum, “Offshore Aquaculture in the Pacific Northwest,” is limited to 125 participants. Information about the program is available online at http://oregonstate.edu/conferences/aquaculture2008/. Open registration begins on July 15.

Chris Langdon, an OSU professor who directs the Molluscan Broodstock Program at the Hatfield Marine Science Center, is coordinating the forum. He says the event is designed to be informational and will explore the potential downsides as well as the rewards of offshore aquaculture in the Northwest region.

“Global population is estimated to increase by another 50 percent in the next 30-40 years and commercial fish stocks around the world are at or above sustainable harvest levels,” Langdon said. “We need to be exploring other avenues of seafood production.

“Any expansion of offshore aquaculture in the United States would require a strong regulatory framework with environmental safeguards to protect natural resources and ensure consumer safety,” he added.

The Pacific Northwest has comparatively clean ocean waters that could allow for production of high-value, cold-water fish and shellfish species.

Speakers at the forum include legislators, community leaders, aquaculture industry representatives, fishing industry representatives, economists and scientists. Among the topics: potential business models for aquaculture, fish and shellfish species suitable for the Pacific Northwest, environmental issues, biological and management issues, and siting and engineering challenges.

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Chris Langdon,
541-867-0231

Lionfish Decimating Other Tropical Fish Populations, Threaten Coral Reefs

CORVALLIS, Ore. – The invasion of predatory lionfish in the Caribbean region poses yet another major threat there to coral reef ecosystems – a new study has found that within a short period after the entry of lionfish into an area, the survival of other reef fishes is slashed by about 80 percent.

Aside from the rapid and immediate mortality of marine life, the loss of herbivorous fish also sets the stage for seaweeds to potentially overwhelm the coral reefs and disrupt the delicate ecological balance in which they exist, according to scientists from Oregon State University.

Following on the heels of overfishing, sediment depositions, nitrate pollution in some areas, coral bleaching caused by global warming, and increasing ocean acidity caused by carbon emissions, the lionfish invasion is a serious concern, said Mark Hixon, an OSU professor of zoology and expert on coral reef ecology.

The study is the first to quantify the severity of the crisis posed by this invasive species, which is native to the tropical Pacific and Indian Ocean and has few natural enemies to help control it in the Atlantic Ocean. It is believed that the first lionfish – a beautiful fish with dramatic coloring and large, spiny fins – were introduced into marine waters off Florida in the early 1990s from local aquariums or fish hobbyists. They have since spread across much of the Caribbean Sea and north along the United States coast as far as Rhode Island.

“This is a new and voracious predator on these coral reefs and it’s undergoing a population explosion,” Hixon said. “The threats to coral reefs all over the world were already extreme, and they now have to deal with this alien predator in the Atlantic. These fish eat many other species and they seem to eat constantly.”

Findings of the new research will be published soon in Marine Ecology Progress Series. The lead author is Mark Albins, a doctoral student working with Hixon.

In studies on controlled plots, the OSU scientists determined that lionfish reduced young juvenile fish populations by 79 percent in only a five-week period. Many species were affected, including cardinalfish, parrotfish, damselfish and others. One large lionfish was observed consuming 20 small fish in a 30-minute period.

Lionfish are carnivores that can eat other fish up to two-thirds their own length, while they are protected from other predators by long, poisonous spines. In the Pacific Ocean, Hixon said, other fish have learned to avoid them and they also have more natural predators, particularly large groupers. In the Atlantic Ocean, native fish have never seen them before and have no recognition of danger. There, about the only thing that will eat lionfish is another lionfish – they are not only aggressive carnivores, but also cannibals.

“In the Caribbean, few local predators eat lionfish, so there appears to be no natural controls on them,” Hixon said. “And we’ve observed that they feed in a way that no Atlantic Ocean fish has ever encountered. Native fish literally don’t know what hit them.”

When attacking another fish, Hixon said, the lionfish will use its large, fan-like fins to herd smaller fish into a corner and then swallow them in a rapid strike. Because of their natural defense mechanisms they are afraid of almost no other marine life. And the poison released by their sharp spines can cause extremely painful stings to humans – even leading to fatalities for some people with heart problems or allergic reactions.

“These are pretty scary fish, and they aren’t timid,” Hixon said. “They will swim right up to a diver in their feeding posture, looking like they’re ready to eat. That can be a little spooky.”

Their rapid reproduction potential, Hixon said, must now be understood in context with their ability to seriously depopulate coral reef ecosystems of other fish. Parrotfishes and other herbivores prevent seaweeds from smothering corals. A major, invasive predator such as lionfish could disrupt the entire system.

Options to manage the lionfish threat are limited, Hixon said. They can be collected individually, which may be of localized value, but that approach offers no broad solution. Recovery or introduction of effective predators might help. Groupers, a fish that has been known to eat lionfish in the Pacific Ocean, have been heavily over-fished in the tropical Atlantic Ocean, Hixon said.

“We have to figure out something to do about this invasion before it causes a major crisis,” Hixon said. “We basically had to abandon some studies we had under way in the Atlantic on population dynamics of coral reef fish, because the lionfish had moved in and were eating everything.”

OSU scientists say they hope to continue research on lionfish in their native Pacific Ocean habitats for information that may be of use in their control.

 

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Mark Hixon,
541-737-5364

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Mark Albins

OSU researcher Mark Albins studying lionfish underwater

New Study: Hatchery fish may hurt efforts to sustain wild salmon runs

CORVALLIS, Ore. – Steelhead trout that are originally bred in hatcheries are so genetically impaired that, even if they survive and reproduce in the wild, their offspring will also be significantly less successful at reproducing, according to a new study published today by researchers from Oregon State University.

The poor reproductive fitness – the ability to survive and reproduce – of the wild-born offspring of hatchery fish means that adding hatchery fish to wild populations may ultimately be hurting efforts to sustain those wild runs, scientists said.

The study found that a fish born in the wild as the offspring of two hatchery-reared steelhead averaged only 37 percent the reproductive fitness of a fish with two wild parents, and 87 percent the fitness if one parent was wild and one was from a hatchery. Most importantly, these differences were still detectable after a full generation of natural selection in the wild.

The effect of hatcheries on reproductive fitness in succeeding generations had been predicted in theory, experts say, but until now had never been demonstrated in actual field experiments.

“If anyone ever had any doubts about the genetic differences between hatchery and wild fish, the data are now pretty clear,” said Michael Blouin, an OSU professor of zoology. “The effect is so strong that it carries over into the first wild-born generation. Even if fish are born in the wild and survive to reproduce, those adults that had hatchery parents still produce substantially fewer surviving offspring than those with wild parents. That’s pretty remarkable.”

An earlier report, published in 2007 in the journal Science, had already shown that hatchery fish that migrate to the ocean and return to spawn leave far fewer offspring than their wild relatives. The newest findings suggest the problem does not end there, but carries over into their wild-born descendants.

The implication, Blouin said, is that hatchery salmonids – many of which do survive to reproduce in the wild– could be gradually reducing the fitness of the wild populations with which they interbreed. Those hatchery fish provide one more hurdle to overcome in the goal of sustaining wild runs, along with problems caused by dams, loss or degradation of habitat, pollution, overfishing and other causes.

Aside from weakening the wild gene pool, the release of captive-bred fish also raises the risk of introducing diseases and increasing competition for limited resources, the report noted.

This research, which was just published in Biology Letters, was supported by grants from the Bonneville Power Administration and the Oregon Department of Fish and Wildlife. It was based on years of genetic analysis of thousands of steelhead trout in Oregon’s Hood River, in field work dating back to 1991. Scientists have been able to genetically “fingerprint” three generations of returning fish to determine who their parents were, and whether or not they were wild or hatchery fish.

The underlying problem, experts say, is Darwinian natural selection.

Fish that do well in the safe, quiet world of the hatcheries are selected to be different than those that do well in a much more hostile and predatory real-world environment. Using wild fish as brood stock each year should lessen the problem, but it was just that type of hatchery fish that were used in the Hood River study. This demonstrates that even a single generation of hatchery culture can still have strong effects.

Although this study was done with steelhead trout, it would be reasonable to extrapolate its results to other salmonids, researchers said. It’s less clear what the findings mean to the many other species that are now being bred in captivity in efforts to help wild populations recover, Blouin said, but it’s possible that similar effects could be found.

Captive breeding is now a cornerstone of recovery efforts by conservation programs for many threatened or endangered species, the researchers noted in their report. Thousands of species may require captive breeding to prevent their extinction in the next 200 years – which makes it particularly important to find out if such programs will ultimately work. This study raises doubts.

“The message should be clear,” the researchers wrote in their report’s conclusion. “Captive breeding for reintroduction or supplementation can have a serious, long-term downside in some taxa, and so should not be considered as a panacea for the recovery of all endangered populations.”

 

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Michael Blouin, 541-737-2362

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Spawning steelhead

Spawning steelhead

 

Salmon

Returning Chinook salmon