Lionfish

There are now 659 less Indo-Pacific red lionfish calling the tranquil waters of the Florida Keys National Marine Sanctuary home.

The end to a bunch of lionfish derbies was held this past Saturday off the lower keys. As you know, these lionfish have been making quite a nuisance of themselves for the past little while, and efforts have been made to get rid of the little rascals, whether it be simple catching, netting in, and even pan frying.

Diving teams managed to round up 109 of these dastardly invaders, adding to the tally of lionfish brought in froIndo-Pacific red lionfish m the previous derbies in Key Largo and Marathon.

Lionfish which are muscling their way into the waters off the southeast United States, Bahamas and Caribbean are causing harm to the native species to those waters as they are chowing down on vital reef species, such as snapper and grouper.

A spokesperson for the Reef Education Foundation, Lad Atkins, has commented that lionfish don’t have any natural enemies, except for us humans.

Concerns are wildly mounting over the presence of Asian carp near Lake Michigan, United States Senator Dick Durbin has bequeathed Obama to elect a Carp Czar, to oversee the efforts to help keep these Asian invaders out of the Great Lakes.

During a news conference at the Shedd Aquarium, Durbin implored.. “We need to have one person who coordinates the efforts of the federal, state and local agencies that are doing everything they can to keep the Asian carp out of Lake Michigan, We believe it’s absolutely essential.”

This was Durbin’s response relating to the amazing discovery of a bighead carp, which is predominantly found in Asia, during the routine sweeps this week at Lake Calumet. The reason this discovery was so alarming is that Lake Calumet is only a stone’s throw away from Lake Michigan.

Durbin is sticking to his guns, lobbying with environmental advocates who have proposed closing Chicago area locks as a way to prevent this carp from getting itself into Lake Michigan. Durbin has called the occurrence “game changing” and has been quoted as saying “we have to take it very seriously.”

Durbin has said that scientists will attempt to find out just exactly where these Asiatic invaders have come from, whether they were dumped into the system, or if it swam its way up the Chicago water system. This will be critical in determining just how many of these Asian carp are making there home in the waters depths.

For the first time, a viral hemorrhagic septicemia virus (VHSV or VHSv) has been identified in fish from Lake Superior, the largest of the five Great Lakes of North America.

The virus was identified by researchers at the Cornell University’s College of Veterinary Medicine and the finding has also been confirmed by the United States Geological Survey’s (USGS) Western Fisheries Research Center in Seattle.

The virus causes viral hemorrhagic septicemia (VHS) in fish and can result in significant losses in wild and captive raised fish populations.

“VHS is one of the most important diseases of finfish,” says James Winton, a VHSV expert working at the Western Fisheries Research Center. “It not only affects the health and well-being of populations of several important native fish species, but it can also impact trade, and, should it spread into the U.S. aquaculture industry, could do substantial damage as happened in Europe and parts of Japan.”

The infection is one of only nine fish diseases that must be reported to the World Organization for Animal Health. Until 2005 it was not known to exist in the Great Lake system but that year it caused several massive die-offs. Since then the virus has been detected in all of the Great Lakes except Lake Superior, and was for instance the culprit when 40,000 freshwater drums died in Lake Ontario over the course of just four days. In addition to the Great Lakes, the virus is also present in the rivers of Niagara and St. Lawrence and in inland lakes in New York, Michigan and Wisconsin.

Previous genetic research carried out by scientists in Canada and the United States show that the VHS virus was probably introduced to the Great Lakes during the last 5-10 years.

Experts now fear that current federal and state restrictions placed upon the movement of fish and fish products won’t be enough to prevent the virus from reaching native fish in the 31 states of the Mississippi River basin.

A marine park will be formed at Camden Sound, Australia, in an effort to protect the Humpback whale (Megaptera novaeangliae). Once hunted to the brink of extinction, the humpbacks have already bounced back considerably thanks to conservation efforts and they are now much sought after by whale-watchers, particularly off parts of Australia, Canada, and the United States.

“The Government recognises the Kimberley as one of Australia’s special places,” said Premier Colin Barnett as he unveiled the plans for the park. “That is why we are protecting Camden Sound, making it a marine park, and developing and implementing our Kimberley Science and Conservation Strategy. This strategy will balance the need to develop industry and create wealth with the expectation that the environment and special places will be protected. This remarkable area warrants protection as a first step in the broader conservation of the Kimberley.”

Environment Minister Donna Faragher added that Camden Sound is the largest calving area for humpbacks in the southern hemisphere.

“More than 1000 humpback whales can be found in the Camden Sound ‘maternity ward’ during the calving season,” Faragher said. “They are part of the biggest population of humpback whales in the world – numbering about 22,000 – that migrate from Antarctica every year to give birth in the waters off the north of our State.”

Faragher said the park will be created in consultation with the local indigenous community and all stakeholders with an interest in the area.

Allowing for consultation, including a public comment period of three months, a marine park could be established as early as mid-2010.

Camden Sound

Camden Sound is a bay in the Indian Ocean situated in the Kimberley region of Western Australia. The sound is a highly bio-diverse region; home to animals such as dugongs, crocodiles, sea-snakes, sharks, rays, and three species of sea turtle. Indo-Pacific humpbacked dolphins, Bottle-nosed dolphins, and the newly recognized Snub-fin dolphin can all be found within the borders of the proposed marine park. The sound is also visited by several species of whale, including False Killer whale, Bryde’s whale, Minke whale, and Dwarf Sperm whale. The corals reefs in the region are still fairly unharmed and varied the extensive mangrove forests found along the shores acts as nursery areas for fish and invertebrates.

Humpback whales born in Camden Sound stay there for several months after birth to grow big and strong enough to survive the long journey to the chilly Arctic waters where the humpbacks feed during the summer.

According to predictions made by a team of NOAA-supported scientists from the Louisiana Universities Marine Consortium, Louisiana State University, and the University of Michigan, the Gulf of Mexico “dead zone” is likely to become record big this summer. If there predictions are true, we will see a dead zone the size of New Jersey (7,450 to 8,456 square miles). Additional flooding of the Mississippi River since May can however increase these numbers even further.

What is the Gulf of Mexico ‘dead zone’?

The dead zone is an area off the coast of Louisiana and Texas in the Gulf of Mexico where the oxygen level seasonally drops so low that most life forms living in and close to the bottom dies.

Dead zones are the result of large amounts of nutrients reaching the water, e.g. through waterways polluted by sewage and agricultural runoff. The excess nutrients stimulate rapid and massive algae growth in the affected area, a so called algae bloom. When the algae die, they sink to the bottom where oxygen dependant bacteria begin to break them down. The decomposition process consumes vast amounts of oxygen and soon the bottom and near-bottom waters become so oxygen depleted that all sorts of oxygen breathing organisms begin to die. This so called hypoxic area (an area where the oxygen levels are low to non-existent) is not just a problem for wildlife; it can also damage the economy of nearby states since it destroys habitat necessary for commercial and recreational Gulf fisheries.

The largest dead zone on record appeared in 2002 and measured 8,484 square miles.

Mississippi and Atchafalaya Rivers too rich in nutrients

During April and May this year, the Mississippi and Atchafalaya Rivers experienced heavy water flows that were 11 percent above average.

“The high water volume flows coupled with nearly triple the nitrogen concentrations in these rivers over the past 50 years from human activities has led to a dramatic increase in the size of the dead zone,” said Gene Turner, Ph.D., a lead forecast modeler from Louisiana State University.

“As with weather forecasts, this forecast uses multiple models to predict the range of the expected size of the dead zone“, said Robert Magnien, Ph.D., director of NOAA’s Center for Sponsored Coastal Ocean Research. “The strong track record of these models reinforces our confidence in the link between excess nutrients from the Mississippi River and the dead zone.”

The famous Sharktooth Hill Bone Bed near Bakersfield has tantalized the imagination of scientists and laymen alike since it was first discovered in the 1850s. How did a six-to-20-inch-thick layer of fossil bones, gigantic shark teeth and turtle shells three times the size of today’s leatherbacks come to be?

Was this a killing ground for C. megalodon, a 40-foot long shark that roamed the seas until 1.5 million years ago? Perhaps a great catastrophe like a red tide or volcanic eruption led to animal mass-death in the region? Or is this simply the result of Sharktooth Hill being used as a breeding ground for generations of marine mammals throughout the millennia?

A research team consisting of palaeontologists from the United States and Canada are now offering their take on the Bone Bed, suggesting it is not the result of a sudden die-off or a certain predator. Instead, the North American team sees it as a 700,000-year record of normal life and death, kept free of sediment by unusual climatic conditions between 15 million and 16 million years ago.

The research team bases its hypothesis on a new and extensive study of the fossils and the geology of Sharktooth Hill. Roughly 3,000 fossilized bone and teeth specimens found in various museums, including the Natural History Museum of Los Angeles County (NHM) and UC Berkeley’s Museum of Paleontology (UCMP), have been scrutinized, and the researchers also cut out a meter-square section of the bone bed, complete with the rock layers above and below.

“If you look at the geology of this fossil bed, it’s not intuitive how it formed,” says Nicholas Pyenson, a former UC Berkeley graduate student who is now a post-doctoral fellow at the University of British Columbia. “We really put together all lines of evidence, with the fossil evidence being a big part of it, to obtain a snapshot of that period of time.”

The existence of a 700,000-year window through which we can catch a glimpse of the past is naturally magnificent news for anyone interested in evolution and Earth’s history.

When the Central Valley was a sea

When the Sharktooth Hill Bone Bed formed between 15,900,000 and 15,200,000 years ago, the climate was warming up, ice was melting and the sea level was much higher than today. What is today California’s Central Valley was an inland sea with the emerging Sierra Nevada as its shoreline.

After closely examining the geology of the Sharktooth Hill area, the research team was able to confirm that it had once been a submerged shelf inside a large embayment, directly opposite a wide opening to the sea.

Several feet of mudstone interlaced with shrimp burrows is present under the bone bed, which is typical of ocean floor sediment several hundred to several thousand feet below the surface. Inside the bone bed, most of the bones have separated joints, indicating that they have been scattered by currents.

“The bones look a bit rotten, as if they lay on the seafloor for a long time and were

abraded by water with sand in it“, says UC Berkeley integrative biology professor Jere Lipps.

Many bones also had manganese nodules and growths on them, something which can form when bones sit in sea water for a long time before they are covered by sediment. According to the team, the most likely explanation for this is that the bones have lain exposed on the ocean floor for 100,000 to 700,000 years while currents have carried sediment around the bone bed. The prevailing climatic conditions at the time have made it possible for the bones to accumulate in a big and shifting pile at the bottom of the sea.

“These animals were dying over the whole area, but no sediment deposition was going on, possibly related to rising sea levels that snuffed out silt and sand deposition or restricted it to the very near-shore environment,” says Pyenson. “Once sea level started going down, then more sediment began to erode from near shore.”

The team discards the breeding-ground hypothesis due to the scarcity of remains from young and juvenile animals. Hungry Megalodon sharks being the main contributors to the bone pile is also unlikely, since few bones bear any marks of shark bites. If the bone bed was the result of mass-death caused by an erupting volcano the absence of volcanic ash in the bed would be very difficult to explain, and the presence of land animals like horses and tapirs that must have washed out to sea make the red-tide hypothesis equally thin.

Amazing remains from the past

The Sharktooth Hill Bone Bed covers nearly 50 square miles just outside and northeast of Bakersfield in California and is one of the richest and most extensive marine deposits of bones in the world. Studied parts of the bone bed average 200 bones per square meter, most of them larger bones. Ten miles of the bed is exposed, and the uppermost part of the bed contains complete, articulated skeletons of whales and seals.

Within the bone bed, scientists have found bones from many species that are now extinct and the bed provides us with invaluable information about the evolutionary history of whales, seals, dolphins, and other marine mammals, as well as of turtles, seabirds and fish. Sharktooth Hill is naturally the sight of some impressive shark findings too, including shark teeth as big as a hand and weighing a pound each.

A small portion of the bone bed was added to the National Natural Landmark registry in 1976 but the rest is in dire need of protection.

A collaborative effort

The research team, who’s study will be published in the June 2009 issue of the journal

Geology, consisted of:

– UC Berkeley integrative biology professor Jere Lipps, who is also a faculty curator in UC Berkeley’s Museum of Paleontology.

– Nicholas Pyenson, a UC Berkeley Ph.D who is now a post-doctoral fellow at the University of British Columbia.

– Randall B. Irmis, a UC Berkeley Ph.D who is now an assistant professor of geology and geophysics at the University of Utah.

– Lawrence G. Barnes, Samuel A. McLeod, and Edward D. Mitchell Jr., three UC Berkeley Ph.D’s who are now with the Department of Vertebrate Paleontology at the Natural History Museum of Los Angeles County.

Just like dolphins, sharks can be trained to roll over to be cuddled by humans. In experiments carried out in the United States, several species of shark allowed themselves to be picked up from the water and cuddled by their trainers.

The U.S. trainers used coloured boards and sounds to train their sharks to respond to commands. No one had attempted to train sharks in this way before and the results are truly ground breaking. Shark keepers now hope that the new technique will give sharks a higher quality of life in captivity. When sharks ned to be moved, the normal practise is to chase them around, but a trained shark could instead be thought to just gently swim to a certain spot.

“The US team has shown that many varieties of sharks can quickly learn to respond to a combination of audible and visual signals”, says Carey Duckhouse of UK’s Sea Life Centres.

Keepers at the UK’s Sea Life Centres are planning to use the methods developed in the U.S. to train sharks kept in British facilities. Colour boards and sounds will be used to show each shark when it is his or her turn to receive food. If everything goes according to plan, the fastest learners in the shark tanks will grasp the idea within three months.

When a shark have learned to associate particular colours and sounds with food, the signals will make it approach its keeper who will be holding a “target stick” against which the shark will rub its nose in hope of getting a tasty treat.

”Some species, such as zebra sharks, will even roll over to have their tummies scratched or allow themselves to be lifted from the water without any kind of struggle,” says Dickhouse.

Modern seals, walruses, and sea lions are all descendants of animals that once lived on land but eventually swapped their terrestrial lifestyle for a life in the ocean. Until now, the morphological evidence for this transition from land to water has been weak, but researchers from Canada and the United States have now found a remarkably well preserved skeleton of a newly discovered carnivorous animal: Puijila darwini.

Skeletal illustration of Puijila darwini.
Credit: Mark A. Klingler/Carnegie Museum of Natural History

Seals, walruses and sea lions all have flippers; a type of limb perfectly adapted for swimming and moving around in water. But how could a land living animal develop flippers? The adaptation evolved gradually over a long period of time, as some land living animals adapted semi-aquatic habits. New research now suggests that the genus Puijila is the “missing” evolutionary link between our modern seals, walruses and sea lions and their terrestrial ancestors.

Puijila darwini is described as having fore-limbs comparatively proportionate to modern carnivorous land animals rather than to pinnepeds*, a long tail, and webbed feet.

“The remarkably preserved skeleton of Puijila had heavy limbs, indicative of well developed muscles, and flattened phalanges which suggests that the feet were webbed, but not flippers. This animal was likely adept at both swimming and walking on land. For swimming it paddled with both front and hind limbs. Puijila is the evolutionary evidence we have been lacking for so long,” says Mary Dawson, curator emeritus of Carnegie Museum of Natural History.

The Puijila darwini skeleton was found in Nunavut, Canada in the remains of what was once a crater lake on coastal Devon Island. The first pieces of the skeleton were found in 2007, but the important basicranium wasn’t found until researchers paid a new visit to the site in 2008. Without a basicranium it is much more difficult to determine taxonomic relationships.

Based on Paleobotanic fossils, Devon Island had a cool, coastal temperate climate during the Miocene when Puijila darwini roamed the seashore. The conditions were quite similar to modern-day New Jersey and the lakes would freeze during the winter, something which probably prompted Puijila darwini to move over land from the lake to the sea in search of food.

“The find suggests that pinnipeds went through a freshwater phase in their evolution. It also provides us with a glimpse of what pinnipeds looked like before they had flippers,” says Natalia Rybczynski, leader of the field expedition.

The idea that semi-aquatic mammals may have undergone a transition from freshwater to saltwater is not new. In the On the Origin of Species by the Means of Natural Selection, Charles Darwin writes “A strictly terrestrial animal, by occasionally hunting for food in shallow water, then in streams or lakes, might at last be converted in an animal so thoroughly aquatic as to brace the open ocean.”

The oldest well-preserved pinniped animal belongs to the genus Enaliarctos and was a sea living creature with flippers. This species has been found on North Americas northern Pacific shores which have lead researchers to believe that the evolution of pinniped animals may have taken place mainly around the Arctic. This new finding of Puijila darwini strengthens that notion.

You can find more information about Puijila darwini and the origin of pinnipeds in the April 23 issue of the journal Nature.

http://www.nature.com

http://www.nature.com/nature/index.html

* The pinnipeds are a widely distributed and diverse group of semi-aquatic marine mammals. It contains the families Odobenidae (walruses), Otariidae (eared seals, including sea lions and fur seals), and Phocidae (earless seals). The name is derived from the Latin words pinna, which means wing or fin, and ped, which means foot. The pinnipeds are therefore also known as fin-footed mammals.

War on clams has been declared at Lake Tahoe, a large freshwater lake in the Sierra Nevada Mountains of the United States. Scuba divers have been enrolled in a 400,000 USD project aiming to completely rid the lake of all Asian clams. The anti-clam endeavour is scheduled to begin in mid-March and is a combined effort by the governments of Nevada and California.

The Asian clam (Corbicula fluminea) is native to Asia and parts of Africa where it inhabits streams, canals and lakes. In this part of the world it is a natural part of the ecosystems and is even known as the prosperity clam or good luck clam. The Asian clam was introduced to North America in the 1920s by Asian immigrants for whom it was an appreciated source of food. It would however take until 2001 before the first specimens were encountered in Lake Tahoe. Since the first finding, the clam has been collected from numerous locations Tahoe’s southeast shore and authorities now fear that it will pave the way for even more dangerous invasive species such as the Ukrainian Quagga mussel (Dreissena rostriformis bugensis) and the Russian Zebra mussel (Dreissena polymorpha).

”We’re concerned they could create a positive settlement situation for the quagga mussels,” says Steve Chilton, aquatic invasive species coordinator for the U.S. Fish and Wildlife Service. ”We’re basically looking at all avenues through which the quagga mussel could get into the lake and eliminate that risk factor as much as possible.”

Steps so far have primarily focused on mandatory boat inspections to ensure no mussels are attached to them when they launch into the lake, but scuba divers participating in the new anti-clam project will actually be removing Asian clams from Lake Tahoe’s southeast shore. Starting in mid-March, divers will place plastic sheets, so called bottom barriers, over selected clam beds in order to deprive the clams of oxygen and nutrients. Divers will also carry out ”diver-assisted suction”, e.g. manually vacuum clams off the bottom of Tahoe.

”This needs to be done. We have to get our hands around the Asian clam problem,” Tahoe Regional Planning Agency spokesman Dennis Oliver told the Reno Gazette-Journal. ”We need to find out what works and what works best. Once we know that, we can develop a program.”

Invasive mussel species are known to form huge populations in environments where they lack natural predators and can for instance clog water intakes, attach themselves to boats and docks, and litter sandy beaches.

North America is not the only continent with an Asian mussel problem; Corbicula fluminea has begun to spread throughout Europe as well. It was found in the Rhine as early in the 1980s and then gradually found its way into the Danube through the Rhine-Maine-Danube Canal. In 1998 the first specimens were found in the Elbe and the species is now also present in the rivers of Portugal.