Mass animal die-offs may be increasing, new research shows

Large numbers of dead sunfish and largemouth bass in April 2014 following a severe winter on Wintergreen Lake, Kalamazoo County, Michigan. (Photo courtesy of G. Mittelbach)

Mass die-offs of animals may be increasing in frequency and — for birds, fishes, and marine invertebrates — in severity as well, according to a study of 727 mass mortality events since 1940.

Despite the ecological importance of individual mass mortality events, in which a larger than normal number of individuals die within a population, little research has been conducted on patterns across mass mortality events. The new study will help researchers better assess trends in mass mortality events and their causes, according to the authors of the paper in the Jan. 12 issue of the Proceedings of the National Academy of Sciences.

“The initial patterns are surprising, in terms of the documented changes to frequencies of occurrences, magnitudes of each event, and the causes of mass mortality,” said Samuel Fey, a postdoctoral fellow in the Department of Ecology and Evolutionary Biology at Yale and co-lead author of the paper. “These data also show that we have a lot of room to improve how we document and study these types of rare events.”

Fey, along with fellow researchers at the University of San Diego and University of California-Berkeley, report that the magnitude of the die-offs has increased in birds, fishes, and marine invertebrates, held steady among mammals, and decreased in frogs and amphibians. The authors recognized that more scientific research has been done on mass mortality events in the last few decades but said even accounting for this “discovery bias” does not explain all of the increase in such events. The increase in mass mortality events appears to be associated with a rise in disease emergence, biotoxicity, and multiple interacting stressors, they note.

Overall, disease was the primary culprit, accounting for 26% of the mass die-offs. The impacts of direct human activity, primarily from environmental contamination, caused 19% of such events. Another major cause was biotoxicity triggered by events such as algae blooms, rapid increases of algae in water systems. Processes directly influenced by climate — such as weather extremes, thermal stress, oxygen stress, or starvation — also contributed accounted collectively for about 25% of mass mortality events.

The most severe events were those with multiple causes, the paper shows.

“This study should improve our understanding of the continuum of mortality patterns and processes that exist between background mortality levels and species-level extinctions,” Fey said.

Adam M. Siepielski of the University of San Diego was co-lead author of the paper. Stephanie M. Carlson of the University of California-Berkeley was senior author. Fey began working on this research while a graduate student at Dartmouth College.

Source: Yale University

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Tailor-made for the aquaculture sector

Details are important. The hood is specially adapted for personnel wearing helmets – without compromising vision. Credit: SINTEF Health Research

Fish husbandry workers have played an active part in developing work clothing tailor-made for their wet, windy and messy working conditions.

They're standing in a small circle around a net pen out in the ocean. Their job is to maintain the net pens, de-louse the salmon, and carry out the many other tasks essential to the running of a fish farm facility. The wind is bitter and the rain is lashing in from all directions. Sea water is splashing around their feet. Everything they handle is wet. Cold water creeps relentlessly up to their knees and along to their elbows inside their coveralls, which are only waterproof up until the second wash.

This is a normal working day for a couple of thousand workers in fish farms all along the Norwegian coast. In spite of this no work clothing exists that is specifically adapted to their very special working conditions. Yet.

Industrial designers Tore Christian Bjørsvik Storholmen and Ole Petter Næsgaard at SINTEF Health Research have developed work clothing which they hope will make conditions both safer and more comfortable for husbandry workers out on the fish farms. Their project has been carried out in close collaboration with the workers who will be wearing the clothing.

Better together

"We've spent a lot of time getting to know the business and the needs of the husbandry workers," says Næsgaard. "We've taken part in many tasks, observed what goes on, and have obtained input and feedback in response to our suggestions," he says. "We've met with a thoroughly honest group of people. They don't hold back when they're not satisfied," he says.

They visited three different facilities close to Hitra and Frøya as part of a pilot project. Ideas and sketches made during one visit were taken to the next so that they could encourage reactions and get feedback. It has been an iterative process involving an ongoing series of corrections and improvements.

"This has served as a quality control on our work to develop relevant and attractive solutions," says Storholmen. "We could never have put the first prototype on the market," he says. "But our dialogue with the users has enabled continuous refinement. New details are always being developed and incorporated. "We're now getting close to a product that can be introduced to the market," he says.

Inspired by climbers and skiers

"When we were studying the husbandry workers, we saw that they do a lot of climbing from boat to boat through ropes and cables and across a variety of different barriers. This led us to obtain inspiration from clothes developed for climbers. The result is that the clothing now offers a very good fit - combined with excellent freedom of movement," explains Storholmen.

When it comes to choosing fabrics, the researchers have obtained greater inspiration from sports clothes than from other types of work clothing. Instead of thick, insulated suits, the new clothing concept has much more in common with kit worn by skiers.

"We've exploited the shell principle," says Storholmen. "The fabric of the outermost layer is water- and wind-proof and very light and durable," he says. "We've also developed intermediate layers and underwear, so users can select the clothing they need based on weather conditions and their own level of activity," he explains.

The clothing is also specifically adapted to allow good freedom of movement in the neck area - even when wearing a life vest. The same applies to the hood which has plenty of room for the mandatory helmet. What about reflective patches? These are placed strategically on the arms, hood and shoulders, and not across the shoulders and legs which is standard for the majority of existing work clothing.

"Actually, we saw that workers testing the clothing were at first sorry to have to return it following the tests," says Storholmen. "This has to be a good sign," he says.

However, the developers are not satisfied simply with anatomical adjustments, new fabrics and good visibility. There has to be a place for modern technology in this type of clothing. So the suit is equipped with a waterproof pocket for a mobile phone, and will also be fitted with a separate pocket to accommodate a man-overboard alarm.

Comfort equals effective HSE

The fish farms visited by the researchers are in exposed coastal locations, often about a half-hour's boat trip from land. The husbandry workers are housed in floating pontoons, surrounded by net pens. They may have to stay here for as much as a week at a time. There have been situations where workers have fallen into the sea. It is essential that the new work clothing represents an improvement in safety. It must be easy for the wearer to get hold of important tools such as knives, tape and communications equipment.

"An Operations Manager told us that good work clothing is one of the most important aids to effective HSE," says Storholmen. "People standing around getting cold lose concentration on what they're doing, making accidents more likely. We believe that this is thoroughly addressed by the new clothing," he says.

A net pen is an enormous "warehouse," and if a major accident occurs, the consequences for the environment and the company's profitability may be very large.

"Aquaculture uniform"

The clothing currently worn by husbandry workers is essentially the same as the standard primarily developed for the building and construction industry, where competitive pricing is a major issue. The clothing being developed in this project will probably be more expensive.

"Current work clothing is a consumer item," say the researchers. "Our impression is that there is a willingness to pay for a better and more durable product specifically adapted to the needs of the aquaculture industry - a specially designed "aquaculture uniform" which can identify the workers and promote an increase in the pride they have in their profession," they say.

Source: SINTEF

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Electric eels deliver taser-like shocks

News research has discovered that the electric eel delivers Taser-like shocks. Credit: Kenneth Catania, Vanderbilt University

The electric eel -- the scaleless Amazonian fish that can deliver an electrical jolt strong enough to knock down a full-grown horse -- possesses an electroshock system uncannily similar to a Taser.

That is the conclusion of a nine-month study of the way in which the electric eel uses high-voltage electrical discharges to locate and incapacitate its prey. The research was conducted by Vanderbilt University Stevenson Professor of Biological Sciences Kenneth Catania and is described in the article "The shocking predatory strike of the electric eel" published in the Dec. 5 issue of the journal Science.

People have known about electric fish for a long time. The ancient Egyptians used an electric marine ray to treat epilepsy. Michael Faraday used eels to investigate the nature of electricity and eel anatomy helped inspire Volta to create the first battery. Biologists have determined that a six-foot electric eel can generate about 600 volts of electricity -- five times that of a U.S. electrical outlet. This summer scientists at the University of Wisconsin-Madison announced that they had sequenced the complete electric eel genome.

Until now, however, no one had figured out how the eel's electroshock system actually worked. In order to do so, Catania equipped a large aquarium with a system that can detect the eel's electric signals and obtained several eels, ranging up to four feet in length.

As he began observing the eels' behavior, the biologist discovered that their movements are incredibly fast. They can strike and swallow a worm or small fish in about a tenth of a second. So Catania rigged up a high-speed video system that ran at a thousand frames per second so he could study the eel's actions in slow motion.

Catania recorded three different kinds of electrical discharges from the eels: low-voltage pulses for sensing their environment; short sequences of two or three high-voltage millisecond pulses (called doublets or triplets) given off while hunting; and volleys of high-voltage, high-frequency pulses when capturing prey or defending themselves from attack.

He found that the eel begins its attack on free-swimming prey with a high-frequency volley of high-voltage pulses about 10 to 15 milliseconds before it strikes. In the high-speed video, it became apparent that the fish were completely immobilized within three to four milliseconds after the volley hit them. The paralysis was temporary: If the eel didn't immediately capture a fish, it normally regained its mobility after a short period and swam away.

"It's amazing. The eel can totally inactivate its prey in just three milliseconds. The fish are completely paralyzed," said Catania.

These observations raised an obvious question: How do the eels do it? For that, there was no clear answer in the scientific literature.

"I have some friends in law enforcement, so I was familiar with how a Taser works," said Catania. "And I was struck by the similarity between the eel's volley and a Taser discharge. A Taser delivers 19 high-voltage pulses per second while the electric eel produces 400 pulses per second."

The Taser works by overwhelming the nerves that control the muscles in the target's body, causing the muscles to involuntarily contract. To determine if the eel's electrical discharge had the same effect, Catania walled off part of the aquarium with an electrically permeable barrier. He placed a pithed fish on other side of the barrier from the eel and then fed the eel some earthworms, which triggered its electrical volleys. The volleys that passed through the barrier and struck the fish produced strong muscle contractions.

To determine whether the discharges were acting on the prey's motor neurons -- the nerves that control the muscles -- or on the muscles themselves, he placed two pithed fish behind the barrier: one injected with saline solution and other injected with curare, a paralytic agent that targets the nervous system. The muscles of the fish with the saline continued to contract in response to the eel's electrical discharges but the muscle contractions in the fish given the curare disappeared as the drug took effect. This demonstrated that the eel's electrical discharges were acting through the motor neurons just like Taser discharges.

Next Catania turned his attention to the way in which the eel uses electrical signals for hunting. The eel is nocturnal and doesn't have very good eyesight. So it needs other ways to detect hidden prey.

The biologist determined that the closely space doublets and triplets that the eel emits correspond to the electric signal that motor neurons send to muscles to produce an extremely rapid contraction.

"Normally, you or I or any other animal can't cause all of the muscles in our body to contract at the same time. However, that is just what the eel can cause with this signal," Catania said.
Putting together the fact that the eels are extremely sensitive to water movements with the fact that the whole-body muscle contraction causes the prey's body to twitch, creating water movements that the eel can sense, Catania concluded that the eel is using these signals to locate hidden prey.

To test this hypothesis, Catania connected a pithed fish to a stimulator.. He put the fish in a clear plastic bag to protect it from the eel's emissions. He found that when he stimulated the fish to twitch right after the eel emitted one of its signals, the eel would attack. But, when the fish failed to respond to its signal, the eel did not attack. The result supports the idea that the eel uses its electroshock system to force its prey to reveal their location.

"If you take a step back and think about it, what the eel can do is extremely remarkable," said Catania. "It can use its electrical system to take remote control of its prey's body. If a fish is hiding nearby, the eel can force it to twitch, giving away its location, and if the eel is ready to capture a fish, it can paralyze it so it can't escape."

The research was funded by a Pradel Award from the National Academy of Sciences, a Guggenheim fellowship and National Science Foundation grant 0844743.

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Source: Vanderbilt University

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Flu at the zoo and other disasters: Experts help animal exhibitors prepare for the worst

After experiencing power outages during a 2007 ice storm in Springfield, Mo., Dickerson Park Zoo officials improved their backup power and heating systems to keep animals -- like Henry, pictured here -- safe and warm. Credit: Dickerson Park Zoo

Here are three disaster scenarios for zoo or aquarium managers: One, a wildfire lunges towards your facility, threatening your staff and hundreds of zoo animals. Two, hurricane floodwaters pour into your basement, where thousands of exotic fish and marine mammals live in giant tanks. Three, local poultry farmers report avian influenza (bird flu) in their chickens, a primary source of protein for your big cats.

What do you do?

These are among the many potential disasters the managers of zoos and aquariums ponder in their emergency preparedness drills and plans. But these stories are not just worst-case scenarios: The events described above actually happened, and the aftermath -- often heroic, and sometimes tragic -- depended in large part on the institutions' preparedness training, planning and forethought in calmer times.

When bad weather strikes or illness invades, zoos and aquariums are among the most vulnerable facilities affected, said University of Illinois veterinarian Yvette Johnson-Walker, a clinical epidemiologist who contributes to emergency response training efforts at animal exhibitor institutions. She is a clinical instructor in the department of veterinary clinical medicine at Illinois, and lead author of a new paper on emergency preparedness at zoos and aquariums in the journal Homeland Security & Emergency Management.

Some animals are likely to suffer if the electricity goes out for long, she said. Others are large, skittish and dangerous under normal conditions.

Training caretakers and keepers to minimize their own risks while attending to their animals in an emergency is a challenge, but leads to the best outcomes, she said.

In 2012, Johnson-Walker joined forces with Yvonne Nadler, a project manager with the Zoo and Aquarium All Hazards Preparedness Response and Recovery Center, to bring vital emergency training to accredited animal exhibitor institutions in Illinois, Indiana and Missouri. This effort, funded by the U.S. Department of Agriculture and supported by the Association of Zoos & Aquariums, has since expanded, providing training to staff from zoos and aquariums in 23 states.

The trainings, dubbed "Flu at the Zoo," focus on avian influenza, a viral disease that spread in the 2000s among wild and captive birds and also infected hundreds of people, primarily in Asia, Africa and the Middle East. Bird flu serves as a useful model scenario to help train participants in basic preparedness skills.

One such skill is familiarity with the Incident Command System (ICS), a framework developed by firefighters and adopted by the Federal Emergency Management Agency (FEMA) that allows first responders to quickly set up their emergency response operation and assign vital tasks. The ICS has long been used by public safety, law enforcement and public health entities involved in emergency response.

"We wanted zoos and aquariums to have a seat at the table when there's planning for how we're going to respond to emergencies, and to be able to fit into the system, know who to talk to and how to communicate," Johnson-Walker said.

It's also important to recognize the other responders and understand their roles, she said. If the event involves a disease like bird flu, the USDA, FEMA, National Institutes of Health, state veterinarian, state and federal wildlife services, public health authorities, veterinary organizations, police, hospitals and perhaps even local poultry operations will be involved in the response. Knowing who does what can speed communication in a crisis.

Planning also helps managers make best use of the limited supplies or equipment they have on hand, Nadler said.

"There are certain types of livestock trailers, for example, that can be adapted to moving big cats," she said. "Is that your preferred method of movement? Of course it isn't, but in an emergency that might be your only option."

One beneficiary of the emergency training, Melinda Arnold, knows firsthand the value of preparedness. Arnold is public relations director for Friends of the Zoo, affiliated with Dickerson Park Zoo in Springfield, Missouri. The zoo suffered a blackout during a 2007 ice storm that shut off power for most of the city for several days.

"We did have backup generators," Arnold said. "The greatest problem with the generators was that those fueling stations in town that did have gas didn't have power, so they couldn't pump the gas."

Zoo staff had to travel many miles outside of the affected area with gas cans to collect gas to run the backup generators, she said.

"Now we have some propane-powered backups," Arnold said.

A more recent incident at the zoo, the accidental death of a zookeeper in 2013, caused Dickerson Park Zoo officials to re-evaluate all of their safety protocols. Even though the zookeeper had decades of experience and was guarded by a protective barrier, a skittish elephant rushed him at an unguarded moment, and he fell and was trampled to death.
"It made us step back, not only in our elephant management but in all areas of the zoo, and look at our safety procedures and points of contact with dangerous animals and evaluate those safety conditions and make improvements," Arnold said.

The preparedness plans, drills, discussions and training all help zoos and aquariums reassess their procedures, even those that seem to be safe after decades of operations and no major incidents, she said.

Source: University of Illinois at Urbana-Champaign

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Climate change projected to drive species northward

Coho salmon are among the species anticipated to shift northward with climate change. Credit: NOAA Fisheries

Anticipated changes in climate will push West Coast marine species from sharks to salmon northward an average of 30 kilometers per decade, shaking up fish communities and shifting fishing grounds, according to a new study published in Progress in Oceanography.

The study suggests that shifting species will likely move into the habitats of other marine life to the north, especially in the Gulf of Alaska and Bering Sea. Some will simultaneously disappear from areas at the southern end of their ranges, especially off Oregon and California.

"As the climate warms, the species will follow the conditions they're adapted to," said Richard Brodeur, a NOAA Fisheries senior scientist at the Northwest Fisheries Science Center's Newport Research Station and coauthor of the study. "We're going to see more interactions between species and there will be winners and losers that we cannot foresee."

The study, led by William Cheung of the University of British Columbia, estimated changes in the distribution of 28 near-surface fish species commonly collected by research surveys in the northeast Pacific Ocean. The researchers used established global climate models to project how the distribution of the fish would shift by 2050 as greenhouse gases warm the atmosphere and, in turn, the ocean surface.

Brodeur cautioned that like any models, climate models carry uncertainty. While they provide a glimpse of the most likely changes in global climate, they may be less accurate when estimating more fine-scale, local changes.

"Nothing is certain," he said, "but we think we have a picture of the most likely changes."
Some species shifts are already being documented as West Coast waters are warming: predatory Humboldt squid from Central and South America have invaded the West Coast of North America in recent years, albacore have shifted to more northerly waters and eulachon have disappeared from warming waters at the southern end of their range.

"Thinking more broadly, this re-shuffling of marine species across the whole biological community may lead to declines in the beneficial functions of marine and coastal ecosystems," said Tom Okey, a Pew Fellow in Marine Conservation at the University of Victoria and a coauthor of the study. "These declines may occur much more rapidly and in more surprising ways than our expected changes in species alone."

The study anticipates warm-water species such as thresher sharks and chub mackerel becoming more prominent in the Gulf of Alaska and off British Columbia. Some predators such as sea lions and seabirds, which rear their young in fixed rookeries or colonies, may find the fish they usually prey on moving beyond predators' usual foraging ranges.

"If their prey moves farther north, they either have to travel farther and expend more energy to get to them, or find something else to eat," Brodeur said. "It's the same thing for fishermen. If it gets warmer, the fish they depend on are going to move up north and that means more travel time and more fuel will be needed to follow them, or else they may need to switch to different target species. It may not happen right away but we are likely to see that kind of a trend."

El Nino years, when tropical influences temporarily warm the eastern Pacific, offer a preview of what to expect as the climate warms.

Shifts in marine communities may be most pronounced in high-latitude regions such as the Gulf of Alaska and Bering Sea, which the study identifies as "hotspots" of change. Cold-water species such as salmon and capelin have narrower temperature preferences than warmer water species, making them more sensitive to ocean warming and likely to respond more quickly.

An intrusion of warm-water species into cooler areas could lead to significant changes in marine communities and ecosystems. The diversity of northern fish communities, now often dominated by a few very prolific species such as walleye pollock, may increase as southern species enter the region, leading to new food web and species interactions.

Source: NOAA Fisheries West Coast Region

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