lunes, 22 de octubre de 2012

A 10-fold rise in Marine Protected Areas has been recorded over a decade.

Hyderabad, UK - A 10-fold rise in Marine Protected Areas has been recorded over a decade.

A report to a UN meeting on biodiversity in Hyderabad reports that more than 8.3 million sq km - 2.3% of the global ocean area - is now protected.

The percentage is small but the rapid growth in recent times leads to hope that the world will hit its target of 10% protected by 2020.

This would have looked most unlikely prospect just a few years ago.

The aspiration was agreed by the Convention on Biological Diversity in 2004 with a target date of 2012. Progress was so slow at first that the target was slipped to 2020 - with some researchers forecasting it would not be reached until mid-century.

But recently there have been huge additions - like Marine Protected Areas (MPAs) in the UK-controlled Chagos archipelago and US-controlled uninhabited territories in the mid-Pacific.

The Cook Islands recently announced a 1.1 million sq km MPA - that is four times the area of the UK land mass. New Caledonia's is even bigger - 1.4 million sq km.

Australia has added a further 2.7 million sq km to its listing of the Great Barrier Reef. Now 28 countries have designated MPAs of more than 10%.

But these statistics may not be quite so impressive as they appear as most of them are far distant from people who would be likely to over-exploit them.

And a recent paper on the demise of the Barrier Reef demonstrates that declaring an area protected does not necessarily shield it from distant influences like over-nutrification.

Mark Spalding from the Nature Conservancy, lead author of the report, told BBC News: "This is great news in the sense that the prospect looked so hopeless until recently. We really should manage to meet the 10% target now.

"But we have to ask whether the targets in themselves are enough - or whether governments need to be smarter to ensure that they're protecting the very most important areas.

"I don't want to knock any of the MPAs but some appear to be easy wins, where you could stick a pin on a map and maybe send a patrol vessel. We need more than that."

Dr Spalding said it was vital now for nations to concentrate efforts on MPAs near heavily-populated coastlines where marine resources were most at risk.

The UK government has been accused of dragging its feet after postponing by a year the introduction of MPAs around the coast of England.

sábado, 20 de octubre de 2012

Passionate opinions voiced at NOAA hearing on 'taking' of beluga whales

Silver Spring, Md. - Passionate statements from aquarium officials and environmental activists alike over the importation of beluga whales resounded in a crowded but quiet meeting room at the National Oceanic and Atmospheric Administration Science Center Friday.
The issue at hand was the Atlanta-based Georgia Aquarium's application for a permit to import 18 beluga whales from Russia. While the Georgia Aquarium is seeking to import the whales, they would go to multiple destinations - possibly including several SeaWorld locations as well as Mystic Aquarium, which currently houses four beluga whales, also known as white whales.
The Marine Mammal Protection Act of 1972 prohibits the "take or import" of marine mammals but includes an exception for animals kept for educational public display or scientific research. NOAA officials held Friday's hearing as part of the process of gathering public comment before making a final decision, which is expected to be issued early next year.
NOAA regulations require only a 30-day public comment period prior to review of such an application, but the comment period for this particular application was extended to 60 days due to increased public interest.
The controversy over the permit request centers around whether these whales are truly being kept for educational purposes, and whether they are being imported in what the Marine Mammal Protection Act defines as a humane manner - or, in the words of the statute, a "method of taking which involves the least possible degree of pain and suffering practicable to the mammal involved."
Naomi Rose, a senior scientist with The Humane Society of the United States, questioned whether the belugas would be transported in a humane manner. Although aquarium officials said that they believed stress associated with capture and transport is short-lived, Rose said her organization disagrees.
"The most likely cause (of death in captive belugas), in my opinion, is chronic stress," she said, citing research conducted at Mystic Aquarium linking transportation and high levels of stress in beluga whales.
The Georgia Aquarium's chief veterinarian, Greg Bossart, sought to emphasize his enterprise's concern for the belugas' welfare and described its medical facilities as one of the largest and most modern aquarium hospitals in the world. Georgia Aquarium's Correll Center includes a surgery suite and a pathology room, along with water quality and diagnostic labs. Bossart also said that the belugas received regular, comprehensive medical exams as well as daily exams from their trainers.
Other objections to the permit request came from scientists and activists who do not consider the exhibits at Georgia Aquarium and SeaWorld parks "educational." Lori Marino, a neuroscientist who studies dolphin and whale intelligence at the Kimmela Center for Animal Advocacy, contended that no one was actually being educated at these locations.
"Theme parks publish material that is often false and misleading on dolphin and whale intelligence," she charged, adding that she believes these organizations downplay the animals' intelligence to rationalize keeping them in captivity.
Marino also described a course at Georgia Aquarium that was marketed as an "animal behavior" class, but which she regarded as a course in "animal husbandry."
But no shortage of educators lined up to defend the Georgia Aquarium, as school principals, teachers, and university professors from the Atlanta region praised the aquarium's beluga exhibit. They were enthusiastic about the hands-on nature of the aquarium, saying that students learned more by actually observing the animals rather than by listening to a lecture.
"With the aquarium, we can make every teacher's words come to life," declared Brian Davis, vice president of education and training at the Georgia Aquarium.

jueves, 18 de octubre de 2012

Misterio en Florida por un globo ocular gigante

Del tamaño de una bola de softbol, los especialistas están a la espera de los análisis genéticos para determinar a qué especie marina pertenece el gran ojo azul

El hallazgo del globo ocular gigante en una playa del sur de Florida ha causado alboroto en internet y en la comunidad de estudio de la biología marina.

El enorme globo ocular azul podría ser el de un calamar de aguas profundas o de un pez espada grande, dijo Heather Bracken-Grissom, profesora asistente en el Programa de Ciencia Marina de la Universidad Internacional de Florida en Miami.
Un hombre encontró el gran ojo cuando paseaba por la mañana en Pompano Beach justo al norte de Fort Lauderdale. Se puso en contacto con funcionarios estatales de vida silvestre, quienes tomaron posesión del globo ocular del tamaño de una bola de softbol.

Bracken-Grissom comentó que tan pronto como llegaron las fotografías el jueves a internet, comenzó a conversar con sus colegas. "Cada vez que algo extraño y demencial es arrastrado a la playa, resulta definitivamente interesante", agregó.

La profesora y sus colegas llegaron a la conclusión de que el cristalino y pupila del globo ocular son similares en forma a los del calamar de aguas profundas. Señaló que el globo ocular de esta especie puede ser tan grande como un balón de softbol y puede dislocarse fácilmente.

El misterio probablemente no se resolverá sino hasta que se terminen los análisis en el Instituto de Investigación de Vida Silvestre y pesca de Florida en St. Petersburg. "Va a ser muy interesante ver qué muestra el análisis genético", dijo Bracken-Grissom.

Añadió que la noticia sobre el globo ocular gigante viajó rápidamente; incluso familiares de California le llamaron por teléfono para preguntarle su opinión. "Algo como esto emociona mucho al público en relación con el misterioso reino del océano", señaló.

martes, 16 de octubre de 2012

Red tide affects Sarasota and Charlotte Beaches

A large red tide bloom, about 12 miles long and six miles wide, is lingering off the Charlotte-Sarasota County coastline and killing fish.

Mote Marine Laboratory publishes a twice-daily beach report that details whether dead fish are on the beach and whether lifeguards or other sentinels are feeling respiratory irritation from red tide.

Statwide red tide sampling results are published online every Friday by the FWRI.

As dead fish began washing ashore on beaches in Englewood this week, hotel owners and tourism officials were hopeful that the problem would not worsen or spread. But more dead fish are likely to land on the region's southern beaches in the coming days, as the bloom creeps north about six to nine miles offshore and winds shift, scientists predicted.

"So far we've been very lucky," said Virginia Haley, president of Visit Sarasota County, noting that "this is generally the time of year when we're going to have problems."

September and October are the most common months for red tide blooms, caused by toxic algae. Almost exactly a year ago a similar red tide bloom sporadically washed dead fish ashore from Venice to Naples for several weeks. A major bloom with widespread, lingering fish kills has not occurred in Southwest Florida since early 2007. Most years bring red tide blooms and fish kills to some part of the region.

Red tide naturally occurs in the Gulf of Mexico. Occasionally conditions allow the algae to accumulate in large numbers, creating a bloom that is deadly for fish, marine mammals, sea turtles and other sea life.

The bloom's toxins also can become airborne, causing significant breathing problems for people with asthma or other respiratory diseases. The toxins also cause healthy people to cough or sniffle.

As of midweek, the red tide effects were limited to southern Sarasota and Charlotte counties. No dead fish or bad air quality were reported on beaches north of Venice.

"There has been no indication of red tide yet, so we have not disturbed our guests and residents about it," said Edward Braunlich, general manager of Hyatt Siesta Key Beach. If the bloom reaches Siesta Key shores this week, Braunlich said precautionary literature will be given to each hotel guest.

Scientists at Mote Marine Laboratory, the University of South Florida and the state Fish and Wildlife Conservation Commission are monitoring the bloom to track its dimensions and location.

Underwater robots that test for the algae will be deployed in a joint experiment between Mote and USF next week, said Jason Lenes, research associate for the Center for Prediction of Red Tides at USF.

He said a cold front sweeping through the region pushed the bloom toward the coast and will shift winds northward after it passes. The change is likely to cause more fish to land on beaches.

"Right now that main patch, the chunk of it, is heading straight north, slightly toward the coast," Lenes said, referring to the red tide outlook for the next three days.

Scientists cannot predict whether the bloom will grow or where it will move beyond about three days, Lenes said.

Sarasota County crews are cleaning up dead fish along Blind Pass and Manasota Key in Englewood, said Curt Preisser, a county spokesman.

In the meantime Mote Marine scientists are "watching beach conditions like hawks," said Barbara Kirkpatrick, senior scientist with the research laboratory in Sarasota.

Scientists will continue to take water samples along the coast this week, concentrating additional effort on Charlotte Harbor.

domingo, 14 de octubre de 2012

Ecologists Start New Antarctic Season

Bozeman, MT — Montana State University ecologists who are about to return to Antarctica for another season had to adapt to dramatic changes in the sea ice last year.

Now they have published a paper that says the Weddell seals they monitor had to deal with some dramatic changes in ice in recent years, too. In fact, the seals handled the adverse conditions well and suffered less than the Emperor penguins in that region.

The paper was published Sept. 26 in the international journal, Proceedings of the Royal Society B: Biological Sciences. Lead author was Thierry Chambert, a doctoral student supervised by co-authors Bob Garrott and Jay Rotella in the MSU ecology department. Rotella and Garrott have just received a National Science Foundation grant for $867,272 that will extend their long-term study by five more years.

Last year, the researchers encountered unusually thin ice that was three feet thick instead of the usual 12 to 16 feet, Garrott said. Large cracks and active breaks threatened snowmobile travel. As a result, the faculty members and students moved their base camp to a safer spot and set up emergency camps around their study area. When they couldn't cross the ice on snowmobiles, they flew by helicopter.

In the course of their work, Rotella said the researchers saw how the Weddell seals faced their own challenges from massive icebergs that broke off and dramatically changed sea-ice conditions in a number of recent years.

Using data from 29 years, the team was able to compare seal numbers, as well as rates of pup production and adult survival, from before, during, and after the iceberg event, to learn how the seals fared. The number of seals they observed and the number of pups that were born during the peak of the iceberg event were down to unprecedented low numbers, but monitoring showed that, "the seals, in fact, handled the event quite well," Rotella said.

He explained that the seals were able to maintain high survival rates by lowering their breeding efforts during the years of iceberg presence. They tended to avoid breeding colonies when sea-ice conditions were particularly unfavorable.

The Emperor penguins, however, continued their normal activities during the worst of the iceberg event. The result was dramatic with dying penguins, as well as breeding failures, Rotella said. He noted that moving ice crushed eggs and even some adults at the peak of the iceberg event. Exhaustion and starvation might also have been an issue for penguins that walked across the ice from open water to their nesting colonies.

"These results reveal that, depending on their ecology, different species can suffer different impacts from an extreme environmental disturbance," said Rotella, the new leader of the Weddell seal study.

"The results also reveal the importance of having long-term data to evaluate possible effects," Rotella continued. "Without the data, we couldn't have known whether this extreme environmental event had extreme consequences for the seals or not. Fortunately for the seals, it did not. We learned that the seals were quite capable of riding out the massive changes in ice conditions as long as they didn't persist too long."

Rotella said the relationship between thinner ice and icebergs is outside of his field of expertise, but he said that ice provides protection from predators like orcas and leopard seals. It also serves as a platform for Weddell seals in the first few weeks of their lives when they have little fat for staying warm in the water and can't swim well yet. When the ice is thinner, predators have better access to the breeding areas used by penguins and Weddell seals for rearing their young. It is also easier for storms to shatter the ice sheets and for the area to have open water.

No one knows what this season will bring for sea-ice conditions, but the MSU researchers said they hope it isn't a repeat of last year.

"That was very challenging," Garrott said. "We really don't know what the ice conditions are like this year until we get down there."

This year's field season will run from about Oct. 10 to mid-December, with Rotella going down for the first half of the season and Garrott for the second half. Mary Lynn Price, a video journalist who has joined the group for the past two seasons, will be there for three weeks in the middle, with her stay overlapping Rotella's and Garrott's.

Price will again produce a variety of videos and other materials that will be available to the public.

This will be the 45th season for the study that Garrott and Rotella took over around 2001 from Don Siniff at the University of Minnesota. Initiated by Siniff, the study is one of the longer running animal population studies and the longest marine mammal study in the southern hemisphere. It not only focuses on changes in the Weddell seal population, but it yields broader information about the workings of the marine environment. The study incorporates information on sea ice, fish, ecosystem dynamics, climate change, and even the Antarctic toothfish, which is marketed in U.S. restaurants as Chilean sea bass.

The MSU study concentrates on pups and adult breeding females that live in the Ross Sea, which is the most pristine ocean left in the world and the only marine system whose top predators -- including the Weddell seal -- still flourish.

The researchers start the season by weighing and tagging every pup when it's about two days old. Later in the season, they visit every colony in their study, collecting genetic samples and recording every tag they find. Weddell seals are relatively gentle for being a top predator in the ecosystem, but they can weigh over 1,000 pounds and have a set of teeth like a bear's, Garrott has said in the past.

viernes, 12 de octubre de 2012

It's not too late for Coral reefs

Fort Lauderdale, FL — Coral reefs -- ecosystems of incredible environmental and economic value -- are showing evidence of significant degradation, but do not have to be doomed. We can make a difference.

Once plentiful, coral reefs worldwide and locally have been ravaged by a number of stresses, including global threats like rising sea temperatures and ocean acidification, and local threats like pollution, overfishing and coastal development. An estimated 25-30 percent of the world's coral reefs are already severely degraded or lost, and another very high percentage are in danger of greater impact or worse. Some even predict reefs could be essentially wiped out within a human generation unless action is taken.

The coral reef issue is not only an environmental problem, but an economic one. The United Nations estimates globally, coral reefs generate over $172 billion per year from the services they provide including tourism, recreation and fisheries. In South Florida alone, where 84 percent of the nation's reefs are located, reef ecosystems have been shown to generate over $6 billion in annual economic contributions and more than 71,000 jobs.

In July, hundreds of scientists joined in a consensus statement written at the recently held 12th International Coral Reef Symposium in Cairns Australia, stating: "Across the globe, these problems cause a loss of reef resources of enormous economic and cultural value. A concerted effort to preserve reefs for the future demands action at global levels, but also will benefit hugely from continued local protection."

Is there good news for the posterity of reefs? There can be. Research is allowing greater understanding about how reefs response to threats. Consequently, there are clear steps that must be taken to ameliorate stresses. Some of these are easy fixes that include stopping overfishing, controlling pollution and establishing marine protected areas. Others, like the rising ocean temperatures that are causing coral bleaching or the increasing acidity in our oceans, are more complex.

Research can also help us learn how to restore these valuable reefs. This includes raising corals in places where larvae and juveniles are nurtured in a relatively safe environment before being moved to a location where we can hope to restore a coral population.

Offshore coral nurseries are showing tremendous potential for restoration. A corollary, and less studied technique, is to grow corals under more controlled conditions in on-land nurseries where they are less subject to stress and variation. These specimens can then be transplanted back to degraded reefs that need a kick start. It's a fairly new idea -- and one among others that we hope will lead to increasing the tools for restoring coral reefs.

Because coral nurseries can play a significant role in restoration, we are expanding our grow-out facilities. With our new reef research facility, the Center of Excellence for Coral Reef Ecosystems Research in Hollywood, Fla., we will triple the size of our land-based coral nursery operation. Our offshore nursery research area with thousands of corals will continue its efforts. We'll use state-of-the-art facilities to study coral stressors in a controlled environment in order to better understand the impacts of these threats and how to better take corrective actions.

There are many unanswered research questions: What size of coral best survives transplantation? When is the optimum time to conduct the transplantation? What genetic strains and mix of a single species will have greatest survivorship? How are the most appropriate species for restoration? How long does it take to restore a reef?

Coral reefs are the rainforests of the sea. And like the Amazonian rainforest that's facing extreme degradation, reefs are disappearing at an alarming rate. We are embarking on a critical mission to understand and restore reef ecosystems. It's a mission that must be accomplished.

miércoles, 10 de octubre de 2012

Why is It illegal ti ride a manatee?

Tampa, FL - Anyone looking for cheap thrills and a quick brush with nature should reconsider thoughts of riding a manatee. As a Florida woman is learning, multiple federal and state laws can be swiftly wielded in defense of the vulnerable sea cow.

Ana Gloria Garcia Gutierrez, 52, accused of riding a manatee in a waterway in Pinellas County over the weekend, turned herself in after authorities on her trail released photos that appear to show her mid-ride.

The Florida Manatee Sanctuary Act outlaws riding or touching the slow-moving marine mammals. And while Gutierrez wasn't immediately charged, her alleged crime is punishable by a $500 fine or a jail term of up to 60 days, according to the Tampa Bay Times.

There was no immediate indication that federal charges would be pressed, but Gutierrez's alleged offense also would violate the Marine Mammal Protection Act and the U.S. Endangered Species Act, under which she could be subject to thousands of dollars in additional fines for harassing a protected species.

Such penalties may seem outsized for a joy ride on a thick-skinned manatee, which was not thought to have been physically injured in the encounter. But authorities' refusal to regard Gutierrez's alleged crime as harmless whimsy is perhaps acknowledgement that human interactions with manatees are precisely what threaten to end the endangered animal's existence.

The same easygoing and curious nature that would likely predispose a manatee to taking on a human passenger seems to contribute to the species' vulnerability to being mowed down by passing speed boats. [Manatee Mystery: Why Can't They Avoid Speedboats?]

About 87 Florida manatees are killed by humans every year, according to the U.S. Fish and Wildlife Service, most of them dying in boat collisions. And with an estimated Florida population of 3,800 manatees, 87 is a grave number.

Coastal development, which has altered and destroyed manatee habitat, also threatens the species.

Swimmers seeking a visceral interaction with a non-manatee marine mammal, take note: Riding a dolphin — the gazelle to the manatee's cow — also violates federal law.

lunes, 8 de octubre de 2012

Lakes React Differently to Warmer Climate

Lund, SWEDEN — A future warmer climate will produce different effects in different lakes. Researchers from Lund University in Sweden have now been able to explain that the effects of climate change depend on what organisms are dominant in the lake. Algal blooms will increase, especially of toxic blue-green algae.

The study in question has been carried out by a group of researchers at the Department of Biology at Lund University. The research team is specifically focusing on predictions regarding how our water resources will be like in the future, in terms of drinking water, recreation, fishing and biodiversity. They have now published findings on the impact of a warmer climate on lakes in the journal Nature Climate Change.

"The most interesting and unexpected result from the study is that the reaction to climate change will vary between lakes; this has been observed previously but has puzzled researchers. We have shown that the variation is dependent on what organisms are dominant in the lake," says Lars-Anders Hansson, Professor of Aquatic Ecology at Lund University.

In lakes without fish, a warmer climate will lead to clear water without algal blooms. However, the results will be different in lakes containing fish. There, the warmer climate will benefit the fish, which will eat up large quantities of crustaceans (zooplankton). These crustaceans keep the algae in check. When the number of crustaceans falls, the algae will be free to multiply, and algal blooms will increase.

"Since most lakes close to humans contain fish and are also already eutrophicated, we can expect to have to deal with algal blooms even more in the future," says Lars-Anders Hansson.

Conditions will be particularly favourable for the development of blue-green algae, and this is an even greater cause for concern, in the view of Lars-Anders Hansson. Blue-green algae, also known as cyanobacteria, are the type of algae that cause the most problems in lakes and oceans because they form very strong and often toxic algal blooms.

The researchers already know that climate change is expected to lead to a rise in temperatures of 2-5o C within the lifetime of the coming generation. An increase in leaching of humus-rich water from land and forests is also expected, which will at least double the brownness of the lake water.

"We know that we are going to see a change in the climate, but we are also seeing other major environmental changes taking place, for example 'brownification'. This means that we have several simultaneous changes that will interact and possibly create synergies," says Lars-Anders Hansson.

In the Future Water research project, a large experiment has been set up based on these conditions, in order to study what impact they may have on organisms and water quality in the future.

sábado, 6 de octubre de 2012

Life Cycle of blue-crab parasite unraveled

Gloucester Point, VA — Professor Jeff Shields and colleagues at the Virginia Institute of Marine Science have succeeded in their 15-year effort to unravel the life history of Hematodinium, a single-celled parasite that afflicts blue crabs and is of growing concern to aquaculture operations and wild fisheries around the world.

Knowledge of the parasite's complex life cycle -- gained by rearing of successive generations across a full year in a VIMS laboratory -- will help guide efforts to understand the transmission of Hematodinium within crab populations and shrimp farms, and to develop best practices for the handling of animals within Virginia's fishery for wild-caught blue crabs.

"Describing the entire life cycle of Hematodinium was an important breakthrough for us," says Shields. "Having all stages in culture means we can now really start picking the life cycle apart to learn what the organism does and how it functions."

One important finding, says Shields, is "that we now know that the development time in culture is around 40-50 days. That matches well with cycles of infection that we see in the field, which we think occur in relation to molting in the blue crab."

"We also now realize that the parasite is a broad host generalist," he adds. "That's important to know for both modeling and management. You can't just fish the blue crabs out of an area and expect to get rid of the pathogen, as it's also present in a number of other host species, including amphipods, fiddler crabs, spider crabs, mud crabs, and other swimming crabs."

The team's achievement -- funded in part by a 5-year grant from the National Science Foundation -- was reported in the journal Parasitology, with Dr. Caiwen Li as lead author. Li authored the paper while a post-doctoral researcher in Shield's Crustacean Diseases Laboratory on the VIMS campus in Gloucester Point; he is now a professor at the Chinese Academy of Sciences' Institute of Oceanology in Qingdao, China.

Hematodinium was first reported from the Eastern Seaboard in the mid-1970s, and first noted in Virginia's blue crabs in the early 1990s. During disease outbreaks, crab mortality can reach 50% in crab pots, and 75% in shedding facilities for soft-shell crabs on Virginia's Eastern Shore. Infections are generally fatal with crabs dying from energy depletion or disruption of bodily tissues. The disease is not harmful to humans.

Dr. Hamish Small­, an assistant research scientist in the Shield's Lab at VIMS, began his career studying Hematodinium in lobsters in his native Scotland. He says, "Hematodinium infections are now increasing in frequency and are being encountered in new hosts and locations worldwide."

Crab growers in China reported their first case of Hematodinium in 2004; and, in 2008, other Chinese growers reported a Hematodinium outbreak in shrimp -- the first time the disease has been noted in this popular aquaculture organism.

The Chinese outbreaks are of concern not only in China, but in the U.S. and other nations as well. NOAA's most recent report on U.S. fisheries notes that more than 90% of the 4.7 billion pounds of seafood consumed in the U.S. in 2011 was imported, with shrimp the most popular item. Moreover, almost half the imports come from aquaculture, with China -- the world's largest aquaculture grower -- producing 32 million metric tons of cultured seafood in 2008.

In a recent theme issue of the Journal of Invertebrate Pathology, Small, Shields, and a host of other crustacean-disease experts from across the globe raise concerns about Hematodinium's growing threat, and its movement between wild and farmed populations. They note that the parasite likely entered the Chinese crab and shrimp farms though the filling of ponds using nearby coastal waters, and caution that it is just as likely to move in the opposite direction -- with transmission from the fertile breeding grounds of crowded crab and shrimp ponds back into wild populations and fisheries.

In a review of Hematodinium's global diversity and distribution -- published as part of the same theme issue -- Small writes "Hematodinium infections have the potential to significantly impact wild host crustacean populations and associated fisheries." In another theme-issue article, Shields notes that Hematodinium may cause more than $500,000 in losses per year to blue crab fishery in Virginia.

Hematodinium most commonly infects younger crabs, with researchers reporting prevalence levels of 50 to 70% among juvenile blue crabs from Virginia's seaside bays. "Infections are most prevalent in saltier waters," says Shields. "You get very high prevalence of infection on the Eastern Shore, and in coastal bays along the entire East Coast of the U.S. It affects the smaller fisheries in the coastal bays."

Shields and his colleagues suspect that the parasite also has a significant indirect impact on the larger blue-crab fishery within Chesapeake Bay, with untold losses due to the death of young crabs before they can complete their migration from coastal spawning grounds into freshwater tributaries where they might otherwise grow big enough to harvest.

"The crabs have to come through high-salinity waters as juveniles," says Shields, "where we find a very high prevalence of the disease. We suspect that Hematodinium induces a fairly high mortality load on the juvenile crabs as they are moving into the Bay. Imagine a harvest with 50% more crabs and the effect of the parasite becomes quite clear."

Recent laboratory experiments by Shields and graduate student Anna Coffey help explain the parasite's inability to survive in fresher waters. Their findings, reported in the June issue of the Journal of Parasitology, show that Hematodinium can develop within the body tissues of blue crabs living in low-salinity conditions, but that the parasite's spores are incapable of transmission in this environment.

"Infected crabs can move into low-salinity waters," says Shields, "but any parasites they release can't survive long enough to infect new crab hosts."

Knowledge of Hematodinium's life cycle and routes of transmission suggests several preventive measures to reduce the parasite's impact on aquaculture operations and wild fisheries.

"Most of our recommendations for the wild fishery involve changes in capture and processing methods," says Shields. "There are low-cost preventative measures to not only stop the spread of disease but to improve the harvest from the soft-shell industry."

Measures to prevent the spread of Hematodinium and other crustacean diseases in aquaculture include isolating ponds from nearby water bodies, stocking ponds with larvae from disease-free hatcheries or from adult crustaceans that have been certified as disease-free, educating farmers about best-management practices, and avoiding the practice of rearing several species together in a single pond, which can encourage transmission of parasites between susceptible crustaceans.

The next frontier in Hematodinium research -- under active pursuit at VIMS with collaborator Professor Kim Reece -- is to improve understanding of the parasite's genetics, so that researchers can more accurately and quickly distinguish between related species and track their interactions as they spread and mingle via ocean currents, natural movements of their hosts, and human activities such as shipping and aquaculture.

"It's difficult to tell different species of Hematodinium apart based just on their external appearance," says Small. "Genetic tools will allow us to more readily compare characteristics like virulence, transmission routes, and potential hosts among different isolates or species."

"The combination of genetic tools with life-cycle studies will make for a powerful approach to understanding this group of parasites," says Shields.