Ballast water is great for stabilizing a ship in rough waters. Unfortunately, it is equally great at carrying all sorts of aquatic organisms across the world before releasing them into new ecosystems where many of them become problematic invasive species.

The cost of invasive species in the Great Lakes of North America have now reached $200 million a year and scientists predict that this number will increase sharply if the dreaded fish virus known as VHS manage to hitchhike its way into Lake Superior. Considering the number of international shipping vessels that arrive to this river system each week, it is probably just a matter of time unless drastic measures are put in place to stop the costly carrying of disruptive stowaways.

Is ballast treatment the solution?
On-board ballast treatment systems have been proposed by parts of the shipping industry as well as by many scientists, but so far, no one has been able come up with an efficient, cost-effective and safe solution that will work in both freshwater and saltwater. Researchers from the Lake Superior Research Institute* in Superior are now trying to change this.

“The question is how clean is clean? Zero would be great, but is it achievable?” asks Mary Balcer, director of the Lake Superior Research Institute.

Balcer, her research team and students at the University of Wisconsin-Superior are currently analyzing a long row of different solutions developed by private companies to see if any of them could help protect environments such as the Great Lakes from the threat of marauding newcomers.

The goal is to find a solution that will eliminate as many living organisms as possible before the ballast water is released. The treatment must also be safe for the ecosystem into which the water will be released.

Freshwater more demanding
Last month, researcher Tom Markee and several students tested using chlorine to eliminate organisms such as tiny worms, midges and water fleas growing in fish tanks in the university lab. Carrying large containers of chlorine on a ship is naturally dangerous, so Markee and his team instead opted for a solution where the treatment system produces its own chlorine by exposing saltwater to an electric current. The goal for Markee et al is now to find the ideal dose of chlorine as well as make sure that the system works in different types of water.

“They’ve tested it in saltwater and it works fine, but when you get to harbors or a river system, that’s when it becomes less effective,” Markee explains.

Other examples of techniques that are being explored by the research institute are the use of ultraviolet light, ozone and even lethal inaudible sound.

Balcer says her research team hasn’t yet found any viable treatment system that would kill all the living organisms in a ballast tank, but she’s happy with the progress that’s been made.

“Everyone’s behind getting the problem solved,” she says. Eventually we’ll be able to find something that really works.”

* Lake Superior Research Institute, http://www.uwsuper.edu/wb/catalog/general/2006-08/programs/LSRI.htm

Have you ever tried to keep a seahorse alive in an aquarium only to fail miserably? Well, to add insult to injury, these creatures seem to be much sturdier than previously believed, because how else can you explain the amazing survival of a British seahorse found three miles inland in Weymouth, Dorset?

“I was just popping out to buy a paper and I looked down and saw this funny object by the pathway, said Karen Warr, 46, who discovered the unusual visitor outside her house. I got a bit closer I saw it was a seahorse. They are very distinctive. I did wonder what on earth it was doing there but I could see it was still breathing so I dashed inside and the only thing I could think of to pick it up with was a fish slice. I put it in the bowl I use for my scales and filled it with tepid water. It was still breathing but wasn’t moving much, it must have been in shock.”

How long the seahorse had been lying on the ground gasping for air is unknown, but Warr put her cat out three hours earlier; a cat fond of eating creatures from the sea. “’It couldn’t have been there then otherwise he would have eaten it”, Warr explained.

After saving the seahorse from suffocation, dehydration and the possible return of the hungry cat, Warr made a call to the nearest Sealife Centre. “I called the Sea Life Centre because they are only down the road and somebody came out to see me.”

The resilient seahorse, an adult female who has been given the name Pegasus, is now recuperating from her adventures in a dark quarantine aquarium at the Sea Life Centre where she is gradually being acclimatized back to saline conditions.

“They can go into shock if they are not treated carefully”, says Display supervisor Claire Little. “She seems fine now but we will continue to monitor her while she is in quarantine for the next 28 days. She has been quite lucky. They are fairly hardy creatures but it was obviously just very good fortune that she was found straight away and we were called.”

Exactly how a seahorse ended up three mile inland remains a mystery, but Warr and Little both agree that it was most likely dropped by a seagull.

A strange algae plume has turned the normally crystal clear Caribbean Sea around the Virgin Islands green down to a depth of roughly 80 feet (25 metres) and sharply decreased visibility in these popular dive waters. How and if the plume will have any long-term effect on the region’s marine life remains unknown.

Tyler Smith, assistant professor at the Center for Marine and Environmental Studies at the University of the Virgin Islands, said that when he went diving Tuesday the visibility inside the plume was no more than 10 feet (3 metres). Below 80 feet, the water was just as clear as normally.

The reason behind the extraordinary plume can be found in South America, in the Orinoco River which flows through Venezuela before reaching the Atlantic Ocean. When the Orinoco outflow is larger than normal, the vast amounts of nutrient-rich freshwater from Venezuela cause a major algae bloom in the nearby ocean. Mixed fresh- and saltwater is lighter than seawater and will therefore rise to the top of the water column.

“It’s very stable, so it just sits there,” Smith explains.

Carried by currents, the algae plume has now spread from the South American east-coast to the Caribbean Sea and can currently be seen not only off the British and U.S. Virgin Islands but in Puerto Rican waters as well. The first patch was noticed by Smith and his colleagues in the waters off St. Croix on April 9.

When the amount of photosynthesising alga increases in a region, it attracts all sorts of organisms that feed on algae and make it possible for these populations to boom as well. The algae plume around the Virgin Islands supports an entire food chain of marine life, including plankton, jellyfish, crustaceans and fish. It is not dangerous to swim or scuba dive in, but some people might dislike the high density of jellyfish.

“This is an event that occurs every year, but we haven’t seen it come this far north,” says Trika Gerard, marine ecologist with the U.S. National Oceanic and Atmospheric Administration (NOAA). In a stroke of good luck, a NOAA research vessel was scheduled to research reef fish in these waters from April 7 to April 20 – right at the peak of the unexpected plume.

To find out more about how the plume effects marine life, the Caribbean Fisheries Management Council is urging anyone who goes out fishing in the green plume to report their location, target species and success rate of each trip. According to local fishermen the fishing is always awfully bad when the water is green, but this has not been scientifically researched yet and all data is of interest.

You can reach the Caribbean Fisheries Management Council by calling (787) 766-5927. Their website is http://www.caribbeanfmc.com.

Chinese ichthyologists Yang, Chen and Yang have described three new species of snow trout in a paper[1] published in the journal Zootaxa[2]. All three species have been described from material previously identified as one single species, Schizothorax griseus. True trouts belong to the Salmoninae subfamily in the Salmonidae family, but snow trouts are members of the family Cyprinidae.

Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Cypriniformes
Family: Cyprinidae
Genus: Schizothorax

New species: Schizothorax beipanensis

Schizothorax heterophysallidos

Schizothorax nudiventris

Schizothorax beipanensis

Schizothorax beipanensis is found in southern China where it inhabits the Beipan River drainage, a part of the Pearl River drainage. It has been encountered in both slow-flowing deep pools and fast-flowing rivers with clear water and over a wide range of different bottom substrate, from mud and sand to rocks, boulders and pebbles.

Schizothorax beipanensis differs from its close relatives by having well-developed upper and lower lips (the lower lip is actually tri-lobed), no horny sheath on the lower jaw, and a continuous postlabial groove with a minute median lobe.

Schizothorax heterophysallidos

Just like Schizothorax beipanensis, the snow trout Schizothorax heterophysallidos is found in the Pearl River drainage in southern China, but it lives in the river drainage of Nanpan, not Beipan. Schizothorax heterophysallidos lives in small streams where the bottom consists of sand and pebbles.

The name heterophysallidos is derived from the unusual swim bladder of this fish; physallis is the Greek word for bladder and heteros means different. In addition to the swim bladder (the posterior chamber of the air bladder is three to six times longer than the anterior chamber), Schizothorax heterophysallidos can be recognized on its well-developed and trilobed lower lip, thin upper lip, and blunt snout. It has a continuous postlabial groove with a minute median lobe and the last unbranched dorsal-fin ray has a strong lower part. In mature specimens, the abdomen lacks scales.

Schizothorax nudiventris

Schizothorax nudiventris also lives in southern China, but in the upper parts of the Mekong River drainage. The Mekong basin is one of the richest areas of biodiversity in the world. More than 1200 species of fish have been identified here and the number is believed to increase as the area becomes more thoroughly explored by science.

Schizothorax nudiventris has a well-developed and trilobed lower lip, thin upper lip, blunt snout, and continuous postlabial groove. The body is decorated with irregular black spots on the sides, and the last one-quarter of the last unbranched dorsal-fin ray is soft. In mature specimens, the abdomen has no scales, and it is this feature that has given the fish its name nudiventris. Nudus is the Latin word for naked, while venter means abdomen.

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.

The Indian government’s Marine Products Export Development Authority (MPEDA) is now launching a breeding program for the threatened Red line torpedo barb (Puntius denisonii).

Torpedo barb – Picture by brookfish

Puntius denisonii, commonly known as Red line torpedo barb, Roseline shark, or Denison barb, is native to the fast-flowing hill streams and rivers in Kerala, at state located in the southern part of India. It is highly sought after in the aquarium trade.

After several years of research, the MPEDA has now managed to successfully breed Red line torpedo barb using two different techniques: one that relies on hormone treatment to trigger spawning and one where the natural breeding conditions of this barb is recreated in captivity.

MPEDA hopes to be starting commercial production shortly.

Picture by brookfish

First of, let me tell everyone how sorry I am that I have been posting a bit sporadic lately. Things have been crazy but hopefully they will improve even though it still might be a couple of weeks until they do. Until then you will unfortunately have to be content with the host I do manage to post. But now, without further ado, on to the Asian arowana

Asian Arowana – Scleropages formosus. Copyright www.jjphoto.dk

Bristol Zoo Gardens have bred the rare Asian Arowana (Scleropages formosus). The spawning resulted in 15 fry which are now estimated to be nine weeks old. The staff did not witness the spawning which is why they can only estimate the age of the fry for this mouth-breeding species. It is not the first time the Asian Arowanas have spawned in Bristol Zoo Gardens, but it is the first time the fry have survived.

Bristol Zoo Gardens has kept four Arowanas, also known as Dragon fish, for 13 years. They received the specimens from the UK custom services who had confiscated them after revealing an attempt to smuggle them into the country.

The zoo has recently taken steps to improve the Arowana exhibit by using reverse osmosis, and has also increased the temperature in the holding tanks. The assistant curator of the aquarium at Bristol Zoo Gardens, Jonny Rudd, believes that one of these actions might be the reason behind the successful breeding. This might very well be true but I also wish to mention the possibility that it might simply have to do with the parents getting more mature and learning from past failures, a well known phenomenon in mouth brooding fish and other fish that care for their young.

This is as far as I know the first time this species have been bred outside Asia.

The Asian Arowana is very rare in the wild and is on the brink of extinction in Thailand. It is red listed by Cites and can not be imported to many countries. This species is bred in farms in Asia where it is a popular exclusive aquarium fish, believed to bring luck due to its resemblance to a dragon. It is today available in a variety of different colorations and morphs. In Asia you can by farm bred fish with certifications stating that they are farm bred and not wild caught, and some countries allow you to import such specimens. You can read more about the Asian Arowana here.

Sri Lankan scientists have described a new species of fish from south-western Sri Lanka and placed in the genus Puntius.

Unlike its close relatives in Sri Lanka and India, the new species Puntius kelumi feature a combination of a smooth last unbranched dorsal-fin ray, a body depth that is 28.6-35.5 % of standard length (SL), maxillary barbels (about as long as the eye diameter) but no rostral barbels, 20-23 lateral-line scales on the body, and ½3/1/2½ scales in transverse line from mid-dorsum to pelvic-fin origin. One breeding males, the sides of the head and body are rough and extensively tuberculated.

Puntius kelumi is primarily found in large streams with clear water that flows down from the mountains. The bottom is typically made up by granite, pebbles and/or sand and is often littered with boulders.

The description was published by the journal Ichthyological Exploration of Freshwaters.

For more information about Puntius kelumi, see the paper: Pethiyagoda, R, A Silva, K Maduwage and M Meegaskumbura (2008) Puntius kelumi, a new species of cyprinid fish from Sri Lanka (Teleostei: Cyprinidae). Ichthyological Exploration of Freshwaters 19, pp. 201–214.

http://www.pfeil-verlag.de/04biol/pdf/ief19_3_02.pdf

A picture of the new species can be seen here

_____________________

Puntius is a genus of ray-finned fishes in the family Cyprinidae. All known members of the genus are native to Southeast Asia and India, including Sri Lanka. The name Puntius is derived from the word pungti, which is the term for small cyprinids in the Bangla (Bengali) language.

Puntius fish are commonly referred to as spotted barbs, but some species display vertical black bands instead of spots. Spotted barbs are commonly kept by aquarists and are known to be active, curious and bold. Many of them are unsuitable companions for fish with long and flowing finnage since they tend to nip such fins, a habit which causes both injury and stress in the afflicted animal.

In May this year, hundreds of Asian swamp eels were discovered in and around Silver Lake in historic Gibbsboro, New Jersey. This was the first finding in New Jersey, Asian swamp eelbut not the first finding in the United States. Unlike Florida, Georgia, and Hawaii – the three other U.S. states where this species have been discovered – New Jersey is however subjected to harsh winters and a breeding population of Asian swamp eels in New Jersey confirms the suspicion that this Asian invader has no problem adjusting to the
chilly climate of northern North America.

The Asian swamp eels were found by a local college student checking on frogs and turtles in the Silver Lake. As he spotted snake-like heads peeking from the water, he decided to photograph them and post the pictures online. This lead to the “snakes” being identified as Asian swamp eels, Monopterus albus, and prompted a call to the local authorities.

In its native environment in Asia and Australia, the swamp eel Monopterus albus inhabits gentle hill streams, estuaries and lowland wetlands, and it is a common species in rice paddies. It has developed a long row of traits that makes it an apt survivor in many different kinds of environments. Unfortunately, these traits also make it the “perfect” invasive species and biologists fear that the Asian swamp eel may wreck havoc with existing North American ecosystems, especially if the predatory species of these systems prefer to target familiar prey rather than catching the newcomers.

– The Asian swamp eel can survive long periods of drought by burrowing in moist earth, and can therefore take advantage of seasonally appearing, short-lived bodies of water.

– If its home becomes unsuitable, e.g. because of drought, this eel simply crawls ashore and make its way to a more suitable home by slithering over land, just like a snake. This makes it hard to eradicate from bodies of water using poison or similar; there is always the risk of at least two specimens getting away over land and forming a new breeding colony in nearby waters.

– The Asian swamp eel can tolerate a wide range of oxygen levels in the water since it is capable of absorbing oxygen from the air above the surface through its skin. This skill doesn’t only come in handy in oxygen depleted waters; it is also what makes it possible for the fish to travel impressive distances over land.

– This eel prefers freshwater habitats, but can tolerate brackish and saline conditions, which increases its chances of always finding a suitable home.

– It eats all sorts of prey, not only fish, crustaceans, amphibians, and other aquatic animals, but detritus (decaying organic matter) as well. Highly specialized feeders have a much harder time adjusting to new habitats and are therefore less likely to become problematic invasive species.

– This eel is a protandrous hermaphrodite, which means that it can change its sex. All specimens are born male, but can turn into females if necessary. This means that if an aquarist releases two male specimens into a lake, one of them can turn into a female to make reproduction possible.

In Georgia, the first specimens of Asian swamp eel was discovered in 1994, and three years later eels were found in Florida as well. The Hawaiian history of combating swamp eels is much longer as the first specimens are believed to have been released in Hawaiian waters about 100 years ago. In Georgia and New Jersey, biologists blame aquarists of having caused the situation by releasing their pets into the wild. In Florida and Hawaii however, Asian food markets and fish-farmers are considered more likely sources. Asian swamp eels are typically sold fresh in food markets and can be kept alive for long periods of time as long as their skin is kept moist.

New Jersey authorities are now focusing on containing the creatures while trying to figure out a way of annihilating them. “We’re not panicking yet,” says Lisa Barno, chief of the New Jersey Bureau of Freshwater Fisheries. “It’s more that it’s just an invasive species we’d rather not have. We’re still documenting the true extent of the problem, but right now it seems to be fairly contained.” One of the immediate goals is to prevent an expansion downstream to the Cooper River and a watershed leading to the Delaware River. Since May, only one Asian swamp eel has been discovered outside the Silver Lake.