Tag Archives: clam


Orange-and-yellow lobster mutant found in Canadian waters

A rare orange-and-yellow lobster has been found off the coast of Prince Edward Island in Canada. Instead of the drab colours normally sported by lobsters, this female specimen boosts a spotted orange-and-yellow pattern. According to specialists, she’s one in about 30 million.

The colourful lobster is currently housed with roughly 100 other lobsters at Arnold’s Lobster and Clam Bar in Eastham, whose owner Nathan “Nick” Nickerson has named her “Fiona” after his girlfriend’s granddaughter. Getting a name is not the only special treatment she’s been awarded; unlike the other inhabitants of the tank her claws are not bound with rubber bands and she can therefore keep her house mates at bay. Lobsters can be cannibalistic, especially in crowded environments, but Nickerson says Fiona is “not very aggressive.”
Arnold’s Lobster and Clam Bar has not put the rare orange-and-yellow lobster on the menu.

“Gosh no!” Nickerson said. “That would be like steaming a Rembrandt.”

Instead, Fiona has gotten used to fine dining at Arnold’s – she’s kept on a diet of Yellowfin tuna of sushi quality while the other lobsters have to make do with cod fish. Nickerson plans on continuing to pamper her for a while before donating her to the Cape Cod Museum of Natural History in Brewster or to the New England Aquarium.

Nickerson received Fiona as a gift from his fried Michael R. Gagne, sales manager at Ipswich Shellfish Company Inc. who says Fiona is a “once-in-a-lifetime lobster”.

1According to Michael F. Tlusty, director of research at the New England Aquarium, Fiona’s distinctive coloration is caused by a rare genetic mutation. He estimated she might be 7 years old based on her weight, but how she managed to survive for so many years in her eye-catching garb is a true mystery.

“If you’re swimming over a muddy bottom, it would be much easier to see a yellow lobster than a normal-colored lobster,” said Tlusty, who has been studying lobsters for 10 years.


“Why was she able to survive with her coloration?”
Tlusty asked. “That’s something we’re not quite sure of.”

War on clams

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.

asian clam

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.

Can bacteria be used to combat invasive mussels from Ukraine?

The U.S. Bureau of Reclamation is now carrying out tests in hope of finding out if bacteria can aid them in their struggle against invasive mussel species that are threatening to spread across the West’s waterways.

During the summer of 2008, a preliminary test was executed at Davis Dam on the Colorado River at Laughlin in Nevada. In this dam, Quagga mussels (Dreissena rostriformis bugensis) were exposed to dead bacteria of the Pseudomonas fluorescens species, a non-infectious bacterium that is commonly found in water, soil and food.

Quagga mussel
Quagga Mussels

During the first test the mussels where exposed to bacteria in jars, but the next test will take place in 10-20 gallon aquariums to in order to more accurately mimic real dam conditions. Water will flow through the aquariums, but will not be released back into the river – it will instead be disposed of through an evaporation pond. A third experiment is also planned, where bacteria will be released in a domestic water intake line which is currently encrusted with a 2-3 inches thick layer of mussels (approximately 5-7.5 cm).

We are always looking for new, more effective techniques for managing mussels, and this one looks very safe and very promising,” says Reclamation scientist Fred Nibling. “We’ll have a series of tests where we’re going to be testing off-line, off the river, so we can have the data to where we can apply for the permits to test elsewhere.

If the initial testing proves to be successful, the Bureau of Reclamation hopes to have a larger scale test approved by the Environmental Protection Agency.

The U.S. Bureau of Reclamation got the idea to use Pseudomonas fluorescens from Daniel Molloy, a researcher at the New York State Museum who discovered that both zebra and quagga mussels died if they ingest the bacterium. He confirmed the effect in 1998 and the method was patented by the museum. Eventually, the Californian firm Marrone Organic Innovations was awarded a National Science Foundation grant to commercialize the technology.

According to Molloy’s research, a mussel needs to ingest a high density of a strain of the bacteria in order for the bacteria to be lethal. If the density is high enough, a toxin inside the bacterium cell will efficiently devastate the digestive tract of the animal.

One advantage with Pseudomonas fluorescens compared to conventional anti-mussel treatments like chlorine is that mussels recognize chlorine as dangerous and close their feeding valves to keep the chemical out. They do however happily devour Pseudomonas fluorescens. Another important aspect is that research has found that Pseudomonas fluorescens does not kill fish or shellfish.

If large scale testing also proves successful, the Bureau of Reclamation say they wish to meet with municipal public works and water authority officials before the bacterium is put into general use. “We want to make sure they’re very comfortable and they have a chance to ask questions,” says Nibbling.

Zenra mussel
Zebra mussels

New gigantic clam found in the Red Sea

A new species of giant clam has been encountered by researchers in the Red Sea and given the name Tridacna costata. The new species is fairly similar to two other well-known species of Red Sea clams and it was therefore first suspect to be a hybrid, but genetic analysis has now deemed it a separate species. Further research carried out in the Red Sea also supports this; there are significant differences in behaviour between the two other species and the newly discovered clam. The two previously known clams spawn during a long period in summer while the new clam spawns during a short period in spring.

Fossil evidence uncovered by researchers has now unveiled something even more interesting; Tridacna costata might be one of the earliest examples of marine overexploitation by humans. Fossil records suggest that the Red Sea Tridacna costata population began do decline rapidly roughly 125,000 years ago. This is the part of our early history when scientists believe modern humans to have first begun to migrate out of Africa. Before this point in history, Tridacna costata accounted for over 80 percent of giant clams in the Red Sea – at least according to current fossil studies. Tridacna costata is a two feet long clam and it is not unreasonable to suspect that it would have been a splendid catch for early humans in search of food. Today, the species is believed to constitute less than one percent of giant clams, but this figure can of course change as the Red Sea becomes even more thoroughly explored.

Tridacna costata is the first new living species of giant clam found in two decades and was accidently discovered by scientists engaged in a Tridacna maxima breeding project. Tridacna maxima, another giant clam, is a much sought after clam in the aquarium trade.

If you want to find out more, the researchers behind the finding have posted their article online in the journal Current Biology on August 28.